MediaCodec
public
final
class
MediaCodec
extends Object
| java.lang.Object | |
| ↳ | android.media.MediaCodec |
MediaCodec class can be used to access low-level media codecs, i.e. encoder/decoder components.
It is part of the Android low-level multimedia support infrastructure (normally used together
with MediaExtractor, MediaSync, MediaMuxer, MediaCrypto,
MediaDrm, Image, Surface, and AudioTrack.)
In broad terms, a codec processes input data to generate output data. It processes data asynchronously and uses a set of input and output buffers. At a simplistic level, you request (or receive) an empty input buffer, fill it up with data and send it to the codec for processing. The codec uses up the data and transforms it into one of its empty output buffers. Finally, you request (or receive) a filled output buffer, consume its contents and release it back to the codec.
Minimum Quality Floor for Video Encoding
Beginning with Build.VERSION_CODES.S, Android's Video MediaCodecs enforce a
minimum quality floor. The intent is to eliminate poor quality video encodings. This quality
floor is applied when the codec is in Variable Bitrate (VBR) mode; it is not applied when
the codec is in Constant Bitrate (CBR) mode. The quality floor enforcement is also restricted
to a particular size range; this size range is currently for video resolutions
larger than 320x240 up through 1920x1080.
When this quality floor is in effect, the codec and supporting framework code will work to ensure that the generated video is of at least a "fair" or "good" quality. The metric used to choose these targets is the VMAF (Video Multi-method Assessment Function) with a target score of 70 for selected test sequences.
The typical effect is that some videos will generate a higher bitrate than originally configured. This will be most notable for videos which were configured with very low bitrates; the codec will use a bitrate that is determined to be more likely to generate an "fair" or "good" quality video. Another situation is where a video includes very complicated content (lots of motion and detail); in such configurations, the codec will use extra bitrate as needed to avoid losing all of the content's finer detail.
This quality floor will not impact content captured at high bitrates (a high bitrate should already provide the codec with sufficient capacity to encode all of the detail). The quality floor does not operate on CBR encodings. The quality floor currently does not operate on resolutions of 320x240 or lower, nor on videos with resolution above 1920x1080.
Data Types
Codecs operate on three kinds of data: compressed data, raw audio data and raw video data.
All three kinds of data can be processed using ByteBuffers, but you should use
a Surface for raw video data to improve codec performance. Surface uses native video
buffers without mapping or copying them to ByteBuffers; thus, it is much more efficient.
You normally cannot access the raw video data when using a Surface, but you can use the
ImageReader class to access unsecured decoded (raw) video frames. This may still be more
efficient than using ByteBuffers, as some native buffers may be mapped into direct ByteBuffers. When using ByteBuffer mode, you can access raw video
frames using the Image class and getInput/OutputImage(int).
Compressed Buffers
Input buffers (for decoders) and output buffers (for encoders) contain compressed data according
to the format's type. For video types this is normally a single
compressed video frame. For audio data this is normally a single access unit (an encoded audio
segment typically containing a few milliseconds of audio as dictated by the format type), but
this requirement is slightly relaxed in that a buffer may contain multiple encoded access units
of audio. In either case, buffers do not start or end on arbitrary byte boundaries, but rather on
frame/access unit boundaries unless they are flagged with BUFFER_FLAG_PARTIAL_FRAME.
Raw Audio Buffers
Raw audio buffers contain entire frames of PCM audio data, which is one sample for each channel
in channel order. Each PCM audio sample is either a 16 bit signed integer or a float,
in native byte order.
Raw audio buffers in the float PCM encoding are only possible
if the MediaFormat's MediaFormat#KEY_PCM_ENCODING
is set to AudioFormat#ENCODING_PCM_FLOAT during MediaCodec
configure(…)
and confirmed by getOutputFormat() for decoders
or getInputFormat() for encoders.
A sample method to check for float PCM in the MediaFormat is as follows:
static boolean isPcmFloat(MediaFormat format) {
return format.getInteger(MediaFormat.KEY_PCM_ENCODING, AudioFormat.ENCODING_PCM_16BIT)
== AudioFormat.ENCODING_PCM_FLOAT;
}
In order to extract, in a short array,
one channel of a buffer containing 16 bit signed integer audio data,
the following code may be used:
// Assumes the buffer PCM encoding is 16 bit.
short[] getSamplesForChannel(MediaCodec codec, int bufferId, int channelIx) {
ByteBuffer outputBuffer = codec.getOutputBuffer(bufferId);
MediaFormat format = codec.getOutputFormat(bufferId);
ShortBuffer samples = outputBuffer.order(ByteOrder.nativeOrder()).asShortBuffer();
int numChannels = format.getInteger(MediaFormat.KEY_CHANNEL_COUNT);
if (channelIx < 0 || channelIx >= numChannels) {
return null;
}
short[] res = new short[samples.remaining() / numChannels];
for (int i = 0; i < res.length; ++i) {
res[i] = samples.get(i * numChannels + channelIx);
}
return res;
}
Raw Video Buffers
In ByteBuffer mode video buffers are laid out according to their color format. You can get the supported color formats as an array
from getCodecInfo().getCapabilitiesForType(…).colorFormats.
Video codecs may support three kinds of color formats:
- native raw video format: This is marked by
CodecCapabilities#COLOR_FormatSurfaceand it can be used with an input or output Surface. - flexible YUV buffers (such as
CodecCapabilities#COLOR_FormatYUV420Flexible): These can be used with an input/output Surface, as well as in ByteBuffer mode, by usinggetInput/OutputImage(int). - other, specific formats: These are normally only supported in ByteBuffer
mode. Some color formats are vendor specific. Others are defined in
CodecCapabilities. For color formats that are equivalent to a flexible format, you can still usegetInput/OutputImage(int).
All video codecs support flexible YUV 4:2:0 buffers since Build.VERSION_CODES.LOLLIPOP_MR1.
Accessing Raw Video ByteBuffers on Older Devices
Prior to Build.VERSION_CODES.LOLLIPOP and Image support, you need to
use the MediaFormat#KEY_STRIDE and MediaFormat#KEY_SLICE_HEIGHT output format
values to understand the layout of the raw output buffers.
Note that on some devices the slice-height is advertised as 0. This could mean either that the
slice-height is the same as the frame height, or that the slice-height is the frame height
aligned to some value (usually a power of 2). Unfortunately, there is no standard and simple way
to tell the actual slice height in this case. Furthermore, the vertical stride of the U
plane in planar formats is also not specified or defined, though usually it is half of the slice
height.
The MediaFormat#KEY_WIDTH and MediaFormat#KEY_HEIGHT keys specify the size of the
video frames; however, for most encondings the video (picture) only occupies a portion of the
video frame. This is represented by the 'crop rectangle'.
You need to use the following keys to get the crop rectangle of raw output images from the output format. If these keys are not present, the video occupies the entire video frame.The crop rectangle is understood in the context of the output frame before applying any rotation.
| Format Key | Type | Description |
|---|---|---|
MediaFormat#KEY_CROP_LEFT |
Integer | The left-coordinate (x) of the crop rectangle |
MediaFormat#KEY_CROP_TOP |
Integer | The top-coordinate (y) of the crop rectangle |
MediaFormat#KEY_CROP_RIGHT |
Integer | The right-coordinate (x) MINUS 1 of the crop rectangle |
MediaFormat#KEY_CROP_BOTTOM |
Integer | The bottom-coordinate (y) MINUS 1 of the crop rectangle |
| The right and bottom coordinates can be understood as the coordinates of the right-most valid column/bottom-most valid row of the cropped output image. | ||
The size of the video frame (before rotation) can be calculated as such:
MediaFormat format = decoder.getOutputFormat(…);
int width = format.getInteger(MediaFormat.KEY_WIDTH);
if (format.containsKey(MediaFormat.KEY_CROP_LEFT)
&& format.containsKey(MediaFormat.KEY_CROP_RIGHT)) {
width = format.getInteger(MediaFormat.KEY_CROP_RIGHT) + 1
- format.getInteger(MediaFormat.KEY_CROP_LEFT);
}
int height = format.getInteger(MediaFormat.KEY_HEIGHT);
if (format.containsKey(MediaFormat.KEY_CROP_TOP)
&& format.containsKey(MediaFormat.KEY_CROP_BOTTOM)) {
height = format.getInteger(MediaFormat.KEY_CROP_BOTTOM) + 1
- format.getInteger(MediaFormat.KEY_CROP_TOP);
}
Also note that the meaning of BufferInfo.offset was not consistent across
devices. On some devices the offset pointed to the top-left pixel of the crop rectangle, while on
most devices it pointed to the top-left pixel of the entire frame.
States
During its life a codec conceptually exists in one of three states: Stopped, Executing or Released. The Stopped collective state is actually the conglomeration of three states: Uninitialized, Configured and Error, whereas the Executing state conceptually progresses through three sub-states: Flushed, Running and End-of-Stream.
When you create a codec using one of the factory methods, the codec is in the Uninitialized
state. First, you need to configure it via configure(…), which brings
it to the Configured state, then call start() to move it to the Executing state. In this
state you can process data through the buffer queue manipulation described above.
The Executing state has three sub-states: Flushed, Running and End-of-Stream. Immediately after
start() the codec is in the Flushed sub-state, where it holds all the buffers. As soon
as the first input buffer is dequeued, the codec moves to the Running sub-state, where it spends
most of its life. When you queue an input buffer with the end-of-stream marker, the codec transitions to the End-of-Stream sub-state. In this state the
codec no longer accepts further input buffers, but still generates output buffers until the
end-of-stream is reached on the output. For decoders, you can move back to the Flushed sub-state
at any time while in the Executing state using flush().
Note: Going back to Flushed state is only supported for decoders, and may not work for encoders (the behavior is undefined).
Call stop() to return the codec to the Uninitialized state, whereupon it may be configured
again. When you are done using a codec, you must release it by calling release().
On rare occasions the codec may encounter an error and move to the Error state. This is
communicated using an invalid return value from a queuing operation, or sometimes via an
exception. Call reset() to make the codec usable again. You can call it from any state to
move the codec back to the Uninitialized state. Otherwise, call release() to move to the
terminal Released state.
Creation
Use MediaCodecList to create a MediaCodec for a specific MediaFormat. When
decoding a file or a stream, you can get the desired format from MediaExtractor.getTrackFormat. Inject any specific features that
you want to add using MediaFormat.setFeatureEnabled, then
call MediaCodecList.findDecoderForFormat to get the
name of a codec that can handle that specific media format. Finally, create the codec using
createByCodecName(String).
Note: On Build.VERSION_CODES.LOLLIPOP, the format to
MediaCodecList.findDecoder/EncoderForFormat must not contain a frame rate. Use
format.setString(MediaFormat.KEY_FRAME_RATE, null)
to clear any existing frame rate setting in the format.
You can also create the preferred codec for a specific MIME type using createDecoder/EncoderByType(java.lang.String).
This, however, cannot be used to inject features, and may create a codec that cannot handle the
specific desired media format.
Creating secure decoders
On versions Build.VERSION_CODES.KITKAT_WATCH and earlier, secure codecs might
not be listed in MediaCodecList, but may still be available on the system. Secure codecs
that exist can be instantiated by name only, by appending ".secure" to the name of a
regular codec (the name of all secure codecs must end in ".secure".) createByCodecName(String) will throw an IOException if the codec is not present on the system.
From Build.VERSION_CODES.LOLLIPOP onwards, you should use the CodecCapabilities#FEATURE_SecurePlayback feature in the media format to create a secure decoder.
Initialization
After creating the codec, you can set a callback using setCallback if you
want to process data asynchronously. Then, configure the codec using the
specific media format. This is when you can specify the output Surface for video
producers – codecs that generate raw video data (e.g. video decoders). This is also when
you can set the decryption parameters for secure codecs (see MediaCrypto). Finally, since
some codecs can operate in multiple modes, you must specify whether you want it to work as a
decoder or an encoder.
Since Build.VERSION_CODES.LOLLIPOP, you can query the resulting input and
output format in the Configured state. You can use this to verify the resulting configuration,
e.g. color formats, before starting the codec.
If you want to process raw input video buffers natively with a video consumer – a codec
that processes raw video input, such as a video encoder – create a destination Surface for
your input data using createInputSurface() after configuration. Alternately, set up the
codec to use a previously created persistent input
surface by calling setInputSurface(Surface).
Encoder Profiles
When using an encoder, it is recommended to set the desired codec profile during configure(). (This is only meaningful for
media formats for which profiles are defined.)
If a profile is not specified during configure, the encoder will choose a profile for the
session based on the available information. We will call this value the default profile.
The selection of the default profile is device specific and may not be deterministic
(could be ad hoc or even experimental). The encoder may choose a default profile that is not
suitable for the intended encoding session, which may result in the encoder ultimately rejecting
the session.
The encoder may reject the encoding session if the configured (or default if unspecified) profile
does not support the codec input (mainly the color format for
video/image codecs, or the sample encoding and the number of channels for audio codecs, but also possibly
width, height,
frame rate, bitrate or
sample rate.)
Alternatively, the encoder may choose to (but is not required to) convert the input to support the
selected (or default) profile - or adjust the chosen profile based on the presumed or detected
input format - to ensure a successful encoding session. Note: Converting the input to match
an incompatible profile will in most cases result in decreased codec performance.
To ensure backward compatibility, the following guarantees are provided by Android:
- The default video encoder profile always supports 8-bit YUV 4:2:0 color format (
COLOR_FormatYUV420Flexibleand equivalentsupported formats) for both Surface and ByteBuffer modes. - The default video encoder profile always supports the default 8-bit RGBA color format in
Surface mode even if no such formats are enumerated in the
supported formats.
Note: the accepted profile can be queried through the output
format of the encoder after configure to allow applications to set up their
codec input to a format supported by the encoder profile.
Implication:
- Applications that want to encode 4:2:2, 4:4:4, 10+ bit or HDR video input MUST configure a suitable profile for encoders.
Codec-specific Data
Some formats, notably AAC audio and MPEG4, H.264 and H.265 video formats require the actual data
to be prefixed by a number of buffers containing setup data, or codec specific data. When
processing such compressed formats, this data must be submitted to the codec after start() and before any frame data. Such data must be marked using the flag BUFFER_FLAG_CODEC_CONFIG in a call to queueInputBuffer.
Codec-specific data can also be included in the format passed to configure in
ByteBuffer entries with keys "csd-0", "csd-1", etc. These keys are always included in the track
MediaFormat obtained from the MediaExtractor.
Codec-specific data in the format is automatically submitted to the codec upon start();
you MUST NOT submit this data explicitly. If the format did not contain codec
specific data, you can choose to submit it using the specified number of buffers in the correct
order, according to the format requirements. In case of H.264 AVC, you can also concatenate all
codec-specific data and submit it as a single codec-config buffer.
Android uses the following codec-specific data buffers. These are also required to be set in
the track format for proper MediaMuxer track configuration. Each parameter set and the
codec-specific-data sections marked with (*) must start with a start code of
"\x00\x00\x00\x01".
| Format | CSD buffer #0 | CSD buffer #1 | CSD buffer #2 |
|---|---|---|---|
| AAC | Decoder-specific information from ESDS* | Not Used | Not Used |
| VORBIS | Identification header | Setup header | Not Used |
| OPUS | Identification header | Pre-skip in nanosecs (unsigned 64-bit native-order integer.) This overrides the pre-skip value in the identification header. |
Seek Pre-roll in nanosecs (unsigned 64-bit native-order integer.) |
| FLAC | "fLaC", the FLAC stream marker in ASCII, followed by the STREAMINFO block (the mandatory metadata block), optionally followed by any number of other metadata blocks |
Not Used | Not Used |
| MPEG-4 | Decoder-specific information from ESDS* | Not Used | Not Used |
| H.264 AVC | SPS (Sequence Parameter Sets*) | PPS (Picture Parameter Sets*) | Not Used |
| H.265 HEVC | VPS (Video Parameter Sets*) + SPS (Sequence Parameter Sets*) + PPS (Picture Parameter Sets*) |
Not Used | Not Used |
| VP9 | VP9 CodecPrivate Data (optional) | Not Used | Not Used |
| AV1 | AV1 AV1CodecConfigurationRecord Data (optional) | Not Used | Not Used |
Note: care must be taken if the codec is flushed immediately or shortly
after start, before any output buffer or output format change has been returned, as the codec
specific data may be lost during the flush. You must resubmit the data using buffers marked with
BUFFER_FLAG_CODEC_CONFIG after such flush to ensure proper codec operation.
Encoders (or codecs that generate compressed data) will create and return the codec specific data before any valid output buffer in output buffers marked with the codec-config flag. Buffers containing codec-specific-data have no meaningful timestamps.
Data Processing
Each codec maintains a set of input and output buffers that are referred to by a buffer-ID in
API calls. After a successful call to start() the client "owns" neither input nor output
buffers. In synchronous mode, call dequeueInput/OutputBuffer(…) to obtain (get ownership of) an input or output
buffer from the codec. In asynchronous mode, you will automatically receive available buffers via
the MediaCodec.Callback.onInput/OutputBufferAvailable(…) callbacks.
Upon obtaining an input buffer, fill it with data and submit it to the codec using queueInputBuffer – or queueSecureInputBuffer if using decryption. Do not submit multiple input buffers with the same
timestamp (unless it is codec-specific data marked as such).
The codec in turn will return a read-only output buffer via the onOutputBufferAvailable callback in asynchronous mode, or in
response to a dequeueOutputBuffer call in synchronous mode. After the
output buffer has been processed, call one of the releaseOutputBuffer methods to return the buffer to the codec.
While you are not required to resubmit/release buffers immediately to the codec, holding onto input and/or output buffers may stall the codec, and this behavior is device dependent. Specifically, it is possible that a codec may hold off on generating output buffers until all outstanding buffers have been released/resubmitted. Therefore, try to hold onto to available buffers as little as possible.
Depending on the API version, you can process data in three ways:
| Processing Mode | API version <= 20 Jelly Bean/KitKat |
API version >= 21 Lollipop and later |
|---|---|---|
| Synchronous API using buffer arrays | Supported | Deprecated |
| Synchronous API using buffers | Not Available | Supported |
| Asynchronous API using buffers | Not Available | Supported |
Asynchronous Processing using Buffers
Since Build.VERSION_CODES.LOLLIPOP, the preferred method is to process data
asynchronously by setting a callback before calling configure. Asynchronous
mode changes the state transitions slightly, because you must call start() after flush() to transition the codec to the Running sub-state and start receiving input buffers.
Similarly, upon an initial call to start the codec will move directly to the Running
sub-state and start passing available input buffers via the callback.
MediaCodec is typically used like this in asynchronous mode:
MediaCodec codec = MediaCodec.createByCodecName(name);
MediaFormat mOutputFormat; // member variable
codec.setCallback(new MediaCodec.Callback() {
@Override
void onInputBufferAvailable(MediaCodec mc, int inputBufferId) {
ByteBuffer inputBuffer = codec.getInputBuffer(inputBufferId);
// fill inputBuffer with valid data
…
codec.queueInputBuffer(inputBufferId, …);
}
@Override
void onOutputBufferAvailable(MediaCodec mc, int outputBufferId, …) {
ByteBuffer outputBuffer = codec.getOutputBuffer(outputBufferId);
MediaFormat bufferFormat = codec.getOutputFormat(outputBufferId); // option A
// bufferFormat is equivalent to mOutputFormat
// outputBuffer is ready to be processed or rendered.
…
codec.releaseOutputBuffer(outputBufferId, …);
}
@Override
void onOutputFormatChanged(MediaCodec mc, MediaFormat format) {
// Subsequent data will conform to new format.
// Can ignore if using getOutputFormat(outputBufferId)
mOutputFormat = format; // option B
}
@Override
void onError(…) {
…
}
@Override
void onCryptoError(…) {
…
}
});
codec.configure(format, …);
mOutputFormat = codec.getOutputFormat(); // option B
codec.start();
// wait for processing to complete
codec.stop();
codec.release();
Synchronous Processing using Buffers
Since Build.VERSION_CODES.LOLLIPOP, you should retrieve input and output
buffers using getInput/OutputBuffer(int) and/or
getInput/OutputImage(int) even when using the
codec in synchronous mode. This allows certain optimizations by the framework, e.g. when
processing dynamic content. This optimization is disabled if you call getInput/OutputBuffers().
Note: do not mix the methods of using buffers and buffer arrays at the same
time. Specifically, only call getInput/OutputBuffers directly after start() or after having dequeued an output buffer ID with the value of INFO_OUTPUT_FORMAT_CHANGED.
MediaCodec is typically used like this in synchronous mode:
MediaCodec codec = MediaCodec.createByCodecName(name);
codec.configure(format, …);
MediaFormat outputFormat = codec.getOutputFormat(); // option B
codec.start();
for (;;) {
int inputBufferId = codec.dequeueInputBuffer(timeoutUs);
if (inputBufferId >= 0) {
ByteBuffer inputBuffer = codec.getInputBuffer(…);
// fill inputBuffer with valid data
…
codec.queueInputBuffer(inputBufferId, …);
}
int outputBufferId = codec.dequeueOutputBuffer(…);
if (outputBufferId >= 0) {
ByteBuffer outputBuffer = codec.getOutputBuffer(outputBufferId);
MediaFormat bufferFormat = codec.getOutputFormat(outputBufferId); // option A
// bufferFormat is identical to outputFormat
// outputBuffer is ready to be processed or rendered.
…
codec.releaseOutputBuffer(outputBufferId, …);
} else if (outputBufferId == MediaCodec.INFO_OUTPUT_FORMAT_CHANGED) {
// Subsequent data will conform to new format.
// Can ignore if using getOutputFormat(outputBufferId)
outputFormat = codec.getOutputFormat(); // option B
}
}
codec.stop();
codec.release();
Synchronous Processing using Buffer Arrays (deprecated)
In versions Build.VERSION_CODES.KITKAT_WATCH and before, the set of input and
output buffers are represented by the ByteBuffer[] arrays. After a successful call to
start(), retrieve the buffer arrays using getInput/OutputBuffers(). Use the buffer ID-s as indices into these arrays (when
non-negative), as demonstrated in the sample below. Note that there is no inherent correlation
between the size of the arrays and the number of input and output buffers used by the system,
although the array size provides an upper bound.
MediaCodec codec = MediaCodec.createByCodecName(name);
codec.configure(format, …);
codec.start();
ByteBuffer[] inputBuffers = codec.getInputBuffers();
ByteBuffer[] outputBuffers = codec.getOutputBuffers();
for (;;) {
int inputBufferId = codec.dequeueInputBuffer(…);
if (inputBufferId >= 0) {
// fill inputBuffers[inputBufferId] with valid data
…
codec.queueInputBuffer(inputBufferId, …);
}
int outputBufferId = codec.dequeueOutputBuffer(…);
if (outputBufferId >= 0) {
// outputBuffers[outputBufferId] is ready to be processed or rendered.
…
codec.releaseOutputBuffer(outputBufferId, …);
} else if (outputBufferId == MediaCodec.INFO_OUTPUT_BUFFERS_CHANGED) {
outputBuffers = codec.getOutputBuffers();
} else if (outputBufferId == MediaCodec.INFO_OUTPUT_FORMAT_CHANGED) {
// Subsequent data will conform to new format.
MediaFormat format = codec.getOutputFormat();
}
}
codec.stop();
codec.release();
End-of-stream Handling
When you reach the end of the input data, you must signal it to the codec by specifying the
BUFFER_FLAG_END_OF_STREAM flag in the call to queueInputBuffer. You can do this on the last valid input buffer, or by submitting an additional
empty input buffer with the end-of-stream flag set. If using an empty buffer, the timestamp will
be ignored.
The codec will continue to return output buffers until it eventually signals the end of the
output stream by specifying the same end-of-stream flag in the BufferInfo set in dequeueOutputBuffer or returned via onOutputBufferAvailable. This can be set on the last valid output buffer, or on an empty buffer
after the last valid output buffer. The timestamp of such empty buffer should be ignored.
Do not submit additional input buffers after signaling the end of the input stream, unless the codec has been flushed, or stopped and restarted.
Using an Output Surface
The data processing is nearly identical to the ByteBuffer mode when using an output Surface; however, the output buffers will not be accessible, and are represented as null
values. E.g. getOutputBuffer/Image(int) will
return null and getOutputBuffers() will return an array containing only null-s.
When using an output Surface, you can select whether or not to render each output buffer on the surface. You have three choices:
- Do not render the buffer: Call
releaseOutputBuffer(bufferId, false). - Render the buffer with the default timestamp: Call
releaseOutputBuffer(bufferId, true). - Render the buffer with a specific timestamp: Call
releaseOutputBuffer(bufferId, timestamp).
Since Build.VERSION_CODES.M, the default timestamp is the presentation timestamp of the buffer (converted to nanoseconds).
It was not defined prior to that.
Also since Build.VERSION_CODES.M, you can change the output Surface
dynamically using setOutputSurface.
When rendering output to a Surface, the Surface may be configured to drop excessive frames (that
are not consumed by the Surface in a timely manner). Or it may be configured to not drop excessive
frames. In the latter mode if the Surface is not consuming output frames fast enough, it will
eventually block the decoder. Prior to Build.VERSION_CODES.Q the exact behavior
was undefined, with the exception that View surfaces (SurfaceView or TextureView) always dropped
excessive frames. Since Build.VERSION_CODES.Q the default behavior is to drop
excessive frames. Applications can opt out of this behavior for non-View surfaces (such as
ImageReader or SurfaceTexture) by targeting SDK Build.VERSION_CODES.Q and
setting the key MediaFormat#KEY_ALLOW_FRAME_DROP to 0
in their configure format.
Transformations When Rendering onto Surface
If the codec is configured into Surface mode, any crop rectangle, rotation and video scaling mode will be automatically applied with one exception:
Prior to the Build.VERSION_CODES.M release, software decoders may not
have applied the rotation when being rendered onto a Surface. Unfortunately, there is no standard
and simple way to identify software decoders, or if they apply the rotation other than by trying
it out.
There are also some caveats.
Note that the pixel aspect ratio is not considered when displaying the output onto the
Surface. This means that if you are using VIDEO_SCALING_MODE_SCALE_TO_FIT mode, you
must position the output Surface so that it has the proper final display aspect ratio. Conversely,
you can only use VIDEO_SCALING_MODE_SCALE_TO_FIT_WITH_CROPPING mode for content with
square pixels (pixel aspect ratio or 1:1).
Note also that as of Build.VERSION_CODES.N release, VIDEO_SCALING_MODE_SCALE_TO_FIT_WITH_CROPPING mode may not work correctly for videos rotated
by 90 or 270 degrees.
When setting the video scaling mode, note that it must be reset after each time the output
buffers change. Since the INFO_OUTPUT_BUFFERS_CHANGED event is deprecated, you can
do this after each time the output format changes.
Using an Input Surface
When using an input Surface, there are no accessible input buffers, as buffers are automatically
passed from the input surface to the codec. Calling dequeueInputBuffer will throw an IllegalStateException, and getInputBuffers()
returns a bogus ByteBuffer[] array that MUST NOT be written into.
Call signalEndOfInputStream() to signal end-of-stream. The input surface will stop
submitting data to the codec immediately after this call.
Seeking & Adaptive Playback Support
Video decoders (and in general codecs that consume compressed video data) behave differently
regarding seek and format change whether or not they support and are configured for adaptive
playback. You can check if a decoder supports adaptive playback via CodecCapabilities.isFeatureSupported(String). Adaptive
playback support for video decoders is only activated if you configure the codec to decode onto a
Surface.
Stream Boundary and Key Frames
It is important that the input data after start() or flush() starts at a suitable
stream boundary: the first frame must be a key frame. A key frame can be decoded
completely on its own (for most codecs this means an I-frame), and no frames that are to be
displayed after a key frame refer to frames before the key frame.
The following table summarizes suitable key frames for various video formats.
| Format | Suitable key frame |
|---|---|
| VP9/VP8 | a suitable intraframe where no subsequent frames refer to frames prior to this frame. (There is no specific name for such key frame.) |
| H.265 HEVC | IDR or CRA |
| H.264 AVC | IDR |
| MPEG-4 H.263 MPEG-2 |
a suitable I-frame where no subsequent frames refer to frames prior to this frame. (There is no specific name for such key frame.) |
For decoders that do not support adaptive playback (including when not decoding onto a Surface)
In order to start decoding data that is not adjacent to previously submitted data (i.e. after a
seek) you MUST flush the decoder. Since all output buffers are immediately
revoked at the point of the flush, you may want to first signal then wait for the end-of-stream
before you call flush. It is important that the input data after a flush starts at a
suitable stream boundary/key frame.
Note: the format of the data submitted after a flush must not change; flush() does not support format discontinuities; for that, a full stop() - configure(…) - start() cycle is necessary.
Also note: if you flush the codec too soon after start() –
generally, before the first output buffer or output format change is received – you
will need to resubmit the codec-specific-data to the codec. See the codec-specific-data section for more info.
For decoders that support and are configured for adaptive playback
In order to start decoding data that is not adjacent to previously submitted data (i.e. after a seek) it is not necessary to flush the decoder; however, input data after the discontinuity must start at a suitable stream boundary/key frame.
For some video formats - namely H.264, H.265, VP8 and VP9 - it is also possible to change the picture size or configuration mid-stream. To do this you must package the entire new codec-specific configuration data together with the key frame into a single buffer (including any start codes), and submit it as a regular input buffer.
You will receive an INFO_OUTPUT_FORMAT_CHANGED return value from dequeueOutputBuffer or a onOutputFormatChanged callback just after the picture-size change takes place and before any
frames with the new size have been returned.
Note: just as the case for codec-specific data, be careful when calling
flush() shortly after you have changed the picture size. If you have not received
confirmation of the picture size change, you will need to repeat the request for the new picture
size.
Error handling
The factory methods createByCodecName and createDecoder/EncoderByType throw IOException on failure
which you must catch or declare to pass up. MediaCodec methods throw IllegalStateException when the method is called from a codec state that does not allow it; this
is typically due to incorrect application API usage. Methods involving secure buffers may throw
CryptoException, which has further error information obtainable from CryptoException#getErrorCode.
Internal codec errors result in a CodecException, which may be due to media content
corruption, hardware failure, resource exhaustion, and so forth, even when the application is
correctly using the API. The recommended action when receiving a CodecException
can be determined by calling CodecException#isRecoverable and CodecException#isTransient:
- recoverable errors: If
isRecoverable()returns true, then callstop(),configure(…), andstart()to recover. - transient errors: If
isTransient()returns true, then resources are temporarily unavailable and the method may be retried at a later time. - fatal errors: If both
isRecoverable()andisTransient()return false, then theCodecExceptionis fatal and the codec must be reset or released.
Both isRecoverable() and isTransient() do not return true at the same time.
Valid API Calls and API History
This sections summarizes the valid API calls in each state and the API history of the MediaCodec
class. For API version numbers, see Build.VERSION_CODES.
| Symbol | Meaning |
|---|---|
| ● | Supported |
| ⁕ | Semantics changed |
| ○ | Experimental support |
| [ ] | Deprecated |
| ⎋ | Restricted to surface input mode |
| ⎆ | Restricted to surface output mode |
| ▧ | Restricted to ByteBuffer input mode |
| ↩ | Restricted to synchronous mode |
| ⇄ | Restricted to asynchronous mode |
| ( ) | Can be called, but shouldn't |
Uninitialized |
Configured |
Flushed |
Running |
End of Stream |
Error |
Released |
SDK Version | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| State | Method | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | ||||||
createByCodecName |
● | ● | ● | ● | ● | ● | ● | ● | |||||||
createDecoderByType |
● | ● | ● | ● | ● | ● | ● | ● | |||||||
createEncoderByType |
● | ● | ● | ● | ● | ● | ● | ● | |||||||
createPersistentInputSurface |
● | ||||||||||||||
| 16+ | - | - | - | - | - | - | configure |
● | ● | ● | ● | ● | ⁕ | ● | ● |
| - | 18+ | - | - | - | - | - | createInputSurface |
⎋ | ⎋ | ⎋ | ⎋ | ⎋ | ⎋ | ||
| - | - | 16+ | 16+ | (16+) | - | - | dequeueInputBuffer |
● | ● | ▧ | ▧ | ▧ | ⁕▧↩ | ▧↩ | ▧↩ |
| - | - | 16+ | 16+ | 16+ | - | - | dequeueOutputBuffer |
● | ● | ● | ● | ● | ⁕↩ | ↩ | ↩ |
| - | - | 16+ | 16+ | 16+ | - | - | flush |
● | ● | ● | ● | ● | ● | ● | ● |
| 18+ | 18+ | 18+ | 18+ | 18+ | 18+ | - | getCodecInfo |
● | ● | ● | ● | ● | ● | ||
| - | - | (21+) | 21+ | (21+) | - | - | getInputBuffer |
● | ● | ● | |||||
| - | - | 16+ | (16+) | (16+) | - | - | getInputBuffers |
● | ● | ● | ● | ● | [⁕↩] | [↩] | [↩] |
| - | 21+ | (21+) | (21+) | (21+) | - | - | getInputFormat |
● | ● | ● | |||||
| - | - | (21+) | 21+ | (21+) | - | - | getInputImage |
○ | ● | ● | |||||
| 18+ | 18+ | 18+ | 18+ | 18+ | 18+ | - | getName |
● | ● | ● | ● | ● | ● | ||
| - | - | (21+) | 21+ | 21+ | - | - | getOutputBuffer |
● | ● | ● | |||||
| - | - | 16+ | 16+ | 16+ | - | - | getOutputBuffers |
● | ● | ● | ● | ● | [⁕↩] | [↩] | [↩] |
| - | 21+ | 16+ | 16+ | 16+ | - | - | getOutputFormat() |
● | ● | ● | ● | ● | ● | ● | ● |
| - | - | (21+) | 21+ | 21+ | - | - | getOutputFormat(int) |
● | ● | ● | |||||
| - | - | (21+) | 21+ | 21+ | - | - | getOutputImage |
○ | ● | ● | |||||
| - | - | - | 16+ | (16+) | - | - | queueInputBuffer |
● | ● | ● | ● | ● | ⁕ | ● | ● |
| - | - | - | 16+ | (16+) | - | - | queueSecureInputBuffer |
● | ● | ● | ● | ● | ⁕ | ● | ● |
| 16+ | 16+ | 16+ | 16+ | 16+ | 16+ | 16+ | release |
● | ● | ● | ● | ● | ● | ● | ● |
| - | - | - | 16+ | 16+ | - | - | releaseOutputBuffer(int, boolean) |
● | ● | ● | ● | ● | ⁕ | ● | ⁕ |
| - | - | - | 21+ | 21+ | - | - | releaseOutputBuffer(int, long) |
⎆ | ⎆ | ⎆ | |||||
| 21+ | 21+ | 21+ | 21+ | 21+ | 21+ | - | reset |
● | ● | ● | |||||
| 21+ | - | - | - | - | - | - | setCallback |
● | ● | ⁕ |
|||||
| - | 23+ | - | - | - | - | - | setInputSurface |
⎋ | |||||||
| 23+ | 23+ | 23+ | 23+ | 23+ | (23+) | (23+) | setOnFrameRenderedListener |
○ ⎆ | |||||||
| - | 23+ | 23+ | 23+ | 23+ | - | - | setOutputSurface |
⎆ | |||||||
| 19+ | 19+ | 19+ | 19+ | 19+ | (19+) | - | setParameters |
● | ● | ● | ● | ● | |||
| - | (16+) | (16+) | 16+ | (16+) | (16+) | - | setVideoScalingMode |
⎆ | ⎆ | ⎆ | ⎆ | ⎆ | ⎆ | ⎆ | ⎆ |
| (29+) | 29+ | 29+ | 29+ | (29+) | (29+) | - | setAudioPresentation |
||||||||
| - | - | 18+ | 18+ | - | - | - | signalEndOfInputStream |
⎋ | ⎋ | ⎋ | ⎋ | ⎋ | ⎋ | ||
| - | 16+ | 21+(⇄) | - | - | - | - | start |
● | ● | ● | ● | ● | ⁕ | ● | ● |
| - | - | 16+ | 16+ | 16+ | - | - | stop |
● | ● | ● | ● | ● | ● | ● | ● |
Summary
Nested classes | |
|---|---|
class |
MediaCodec.BufferInfo
Per buffer metadata includes an offset and size specifying the range of valid data in the associated codec (output) buffer. |
class |
MediaCodec.Callback
MediaCodec callback interface. |
class |
MediaCodec.CodecException
Thrown when an internal codec error occurs. |
class |
MediaCodec.CryptoException
Thrown when a crypto error occurs while queueing a secure input buffer. |
class |
MediaCodec.CryptoInfo
Metadata describing the structure of an encrypted input sample. |
class |
MediaCodec.IncompatibleWithBlockModelException
Thrown when the codec is configured for block model and an incompatible API is called. |
class |
MediaCodec.InvalidBufferFlagsException
Thrown when a buffer is marked with an invalid combination of flags
(e.g. both |
class |
MediaCodec.LinearBlock
Section of memory that represents a linear block. |
class |
MediaCodec.MetricsConstants
|
interface |
MediaCodec.OnFirstTunnelFrameReadyListener
Listener to be called when the first output frame has been decoded
and is ready to be rendered for a codec configured for tunnel mode with
|
interface |
MediaCodec.OnFrameRenderedListener
Listener to be called when an output frame has rendered on the output surface |
class |
MediaCodec.OutputFrame
A single output frame and its associated metadata. |
class |
MediaCodec.ParameterDescriptor
Contains description of a parameter. |
class |
MediaCodec.QueueRequest
Builder-like class for queue requests. |
Constants | |
|---|---|
int |
BUFFER_FLAG_CODEC_CONFIG
This indicated that the buffer marked as such contains codec initialization / codec specific data instead of media data. |
int |
BUFFER_FLAG_DECODE_ONLY
This indicates that the buffer is decoded and updates the internal state of the decoder, but does not produce any output buffer. |
int |
BUFFER_FLAG_END_OF_STREAM
This signals the end of stream, i.e. |
int |
BUFFER_FLAG_KEY_FRAME
This indicates that the (encoded) buffer marked as such contains the data for a key frame. |
int |
BUFFER_FLAG_PARTIAL_FRAME
This indicates that the buffer only contains part of a frame, and the decoder should batch the data until a buffer without this flag appears before decoding the frame. |
int |
BUFFER_FLAG_SYNC_FRAME
This constant was deprecated
in API level 21.
Use |
int |
CONFIGURE_FLAG_DETACHED_SURFACE
Configure the codec with a detached output surface. |
int |
CONFIGURE_FLAG_ENCODE
If this codec is to be used as an encoder, pass this flag. |
int |
CONFIGURE_FLAG_USE_BLOCK_MODEL
If this codec is to be used with |
int |
CONFIGURE_FLAG_USE_CRYPTO_ASYNC
This flag should be used on a secure decoder only. |
int |
CRYPTO_MODE_AES_CBC
|
int |
CRYPTO_MODE_AES_CTR
|
int |
CRYPTO_MODE_UNENCRYPTED
|
int |
INFO_OUTPUT_BUFFERS_CHANGED
This constant was deprecated
in API level 21.
This return value can be ignored as |
int |
INFO_OUTPUT_FORMAT_CHANGED
The output format has changed, subsequent data will follow the new format. |
int |
INFO_TRY_AGAIN_LATER
If a non-negative timeout had been specified in the call
to |
String |
PARAMETER_KEY_HDR10_PLUS_INFO
Set the HDR10+ metadata on the next queued input frame. |
String |
PARAMETER_KEY_LOW_LATENCY
Enable/disable low latency decoding mode. |
String |
PARAMETER_KEY_OFFSET_TIME
Specify an offset (in micro-second) to be added on top of the timestamps onward. |
String |
PARAMETER_KEY_QP_OFFSET_MAP
Set the region of interest as QpOffset-Map on the next queued input frame. |
String |
PARAMETER_KEY_QP_OFFSET_RECTS
Set the region of interest as QpOffset-Rects on the next queued input frame. |
String |
PARAMETER_KEY_REQUEST_SYNC_FRAME
Request that the encoder produce a sync frame "soon". |
String |
PARAMETER_KEY_SUSPEND
Temporarily suspend/resume encoding of input data. |
String |
PARAMETER_KEY_SUSPEND_TIME
When |
String |
PARAMETER_KEY_TUNNEL_PEEK
Control video peek of the first frame when a codec is configured for tunnel mode with
|
String |
PARAMETER_KEY_VIDEO_BITRATE
Change a video encoder's target bitrate on the fly. |
int |
VIDEO_SCALING_MODE_SCALE_TO_FIT
The content is scaled to the surface dimensions |
int |
VIDEO_SCALING_MODE_SCALE_TO_FIT_WITH_CROPPING
The content is scaled, maintaining its aspect ratio, the whole surface area is used, content may be cropped. |
Public methods | |
|---|---|
void
|
configure(MediaFormat format, Surface surface, MediaCrypto crypto, int flags)
Configures a component. |
void
|
configure(MediaFormat format, Surface surface, int flags, MediaDescrambler descrambler)
Configure a component to be used with a descrambler. |
static
MediaCodec
|
createByCodecName(String name)
If you know the exact name of the component you want to instantiate use this method to instantiate it. |
static
MediaCodec
|
createDecoderByType(String type)
Instantiate the preferred decoder supporting input data of the given mime type. |
static
MediaCodec
|
createEncoderByType(String type)
Instantiate the preferred encoder supporting output data of the given mime type. |
Surface
|
createInputSurface()
Requests a Surface to use as the input to an encoder, in place of input buffers. |
static
Surface
|
createPersistentInputSurface()
Create a persistent input surface that can be used with codecs that normally have an input surface, such as video encoders. |
int
|
dequeueInputBuffer(long timeoutUs)
Returns the index of an input buffer to be filled with valid data or -1 if no such buffer is currently available. |
int
|
dequeueOutputBuffer(MediaCodec.BufferInfo info, long timeoutUs)
Dequeue an output buffer, block at most "timeoutUs" microseconds. |
void
|
detachOutputSurface()
Detach the current output surface of a codec. |
void
|
flush()
Flush both input and output ports of the component. |
String
|
getCanonicalName()
Retrieve the underlying codec name. |
MediaCodecInfo
|
getCodecInfo()
Get the codec info. |
ByteBuffer
|
getInputBuffer(int index)
Returns a |
ByteBuffer[]
|
getInputBuffers()
This method was deprecated
in API level 21.
Use the new |
MediaFormat
|
getInputFormat()
Call this after |
Image
|
getInputImage(int index)
Returns a writable Image object for a dequeued input buffer index to contain the raw input video frame. |
PersistableBundle
|
getMetrics()
Return Metrics data about the current codec instance. |
String
|
getName()
Retrieve the codec name. |
ByteBuffer
|
getOutputBuffer(int index)
Returns a read-only ByteBuffer for a dequeued output buffer index. |
ByteBuffer[]
|
getOutputBuffers()
This method was deprecated
in API level 21.
Use the new |
MediaFormat
|
getOutputFormat(int index)
Returns the output format for a specific output buffer. |
MediaFormat
|
getOutputFormat()
Call this after dequeueOutputBuffer signals a format change by returning
|
MediaCodec.OutputFrame
|
getOutputFrame(int index)
Returns an |
Image
|
getOutputImage(int index)
Returns a read-only Image object for a dequeued output buffer index that contains the raw video frame. |
MediaCodec.ParameterDescriptor
|
getParameterDescriptor(String name)
Describe a parameter with the name. |
MediaCodec.QueueRequest
|
getQueueRequest(int index)
Return a |
List<String>
|
getSupportedVendorParameters()
Returns a list of vendor parameter names. |
static
Image
|
mapHardwareBuffer(HardwareBuffer hardwareBuffer)
Map a |
void
|
queueInputBuffer(int index, int offset, int size, long presentationTimeUs, int flags)
After filling a range of the input buffer at the specified index submit it to the component. |
void
|
queueInputBuffers(int index, ArrayDeque<MediaCodec.BufferInfo> bufferInfos)
Submit multiple access units to the codec along with multiple
|
void
|
queueSecureInputBuffer(int index, int offset, MediaCodec.CryptoInfo info, long presentationTimeUs, int flags)
Similar to |
void
|
queueSecureInputBuffers(int index, ArrayDeque<MediaCodec.BufferInfo> bufferInfos, ArrayDeque<MediaCodec.CryptoInfo> cryptoInfos)
Similar to |
void
|
release()
Free up resources used by the codec instance. |
void
|
releaseOutputBuffer(int index, boolean render)
If you are done with a buffer, use this call to return the buffer to the codec or to render it on the output surface. |
void
|
releaseOutputBuffer(int index, long renderTimestampNs)
If you are done with a buffer, use this call to update its surface timestamp and return it to the codec to render it on the output surface. |
void
|
reset()
Returns the codec to its initial (Uninitialized) state. |
void
|
setAudioPresentation(AudioPresentation presentation)
Sets the audio presentation. |
void
|
setCallback(MediaCodec.Callback cb, Handler handler)
Sets an asynchronous callback for actionable MediaCodec events. |
void
|
setCallback(MediaCodec.Callback cb)
Sets an asynchronous callback for actionable MediaCodec events on the default looper. |
void
|
setInputSurface(Surface surface)
Configures the codec (e.g. encoder) to use a persistent input surface in place of input buffers. |
void
|
setOnFirstTunnelFrameReadyListener(Handler handler, MediaCodec.OnFirstTunnelFrameReadyListener listener)
Registers a callback to be invoked when the first output frame has been decoded
and is ready to be rendered on a codec configured for tunnel mode with |
void
|
setOnFrameRenderedListener(MediaCodec.OnFrameRenderedListener listener, Handler handler)
Registers a callback to be invoked when an output frame is rendered on the output surface. |
void
|
setOutputSurface(Surface surface)
Dynamically sets the output surface of a codec. |
void
|
setParameters(Bundle params)
Communicate additional parameter changes to the component instance. |
void
|
setVideoScalingMode(int mode)
If a surface has been specified in a previous call to |
void
|
signalEndOfInputStream()
Signals end-of-stream on input. |
void
|
start()
After successfully configuring the component, call |
void
|
stop()
Finish the decode/encode session, note that the codec instance
remains active and ready to be |
void
|
subscribeToVendorParameters(List<String> names)
Subscribe to vendor parameters, so that these parameters will be present in
|
void
|
unsubscribeFromVendorParameters(List<String> names)
Unsubscribe from vendor parameters, so that these parameters will not be present in
|
Protected methods | |
|---|---|
void
|
finalize()
Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. |
Inherited methods | |
|---|---|
Constants
BUFFER_FLAG_CODEC_CONFIG
public static final int BUFFER_FLAG_CODEC_CONFIG
This indicated that the buffer marked as such contains codec initialization / codec specific data instead of media data.
Constant Value: 2 (0x00000002)
BUFFER_FLAG_DECODE_ONLY
public static final int BUFFER_FLAG_DECODE_ONLY
This indicates that the buffer is decoded and updates the internal state of the decoder,
but does not produce any output buffer.
When a buffer has this flag set,
OnFrameRenderedListener#onFrameRendered(MediaCodec, long, long) and
Callback#onOutputBufferAvailable(MediaCodec, int, BufferInfo) will not be called for
that given buffer.
For example, when seeking to a certain frame, that frame may need to reference previous
frames in order for it to produce output. The preceding frames can be marked with this flag
so that they are only decoded and their data is used when decoding the latter frame that
should be initially displayed post-seek.
Another example would be trick play, trick play is when a video is fast-forwarded and only a
subset of the frames is to be rendered on the screen. The frames not to be rendered can be
marked with this flag for the same reason as the above one.
Marking frames with this flag improves the overall performance of playing a video stream as
fewer frames need to be passed back to the app.
In CodecCapabilities#FEATURE_TunneledPlayback, buffers marked with this flag
are not rendered on the output surface.
A frame should not be marked with this flag and BUFFER_FLAG_END_OF_STREAM
simultaneously, doing so will produce a InvalidBufferFlagsException
Constant Value: 32 (0x00000020)
BUFFER_FLAG_END_OF_STREAM
public static final int BUFFER_FLAG_END_OF_STREAM
This signals the end of stream, i.e. no buffers will be available
after this, unless of course, flush() follows.
Constant Value: 4 (0x00000004)
BUFFER_FLAG_KEY_FRAME
public static final int BUFFER_FLAG_KEY_FRAME
This indicates that the (encoded) buffer marked as such contains the data for a key frame.
Constant Value: 1 (0x00000001)
BUFFER_FLAG_PARTIAL_FRAME
public static final int BUFFER_FLAG_PARTIAL_FRAME
This indicates that the buffer only contains part of a frame, and the decoder should batch the data until a buffer without this flag appears before decoding the frame.
Constant Value: 8 (0x00000008)
BUFFER_FLAG_SYNC_FRAME
public static final int BUFFER_FLAG_SYNC_FRAME
This constant was deprecated
in API level 21.
Use BUFFER_FLAG_KEY_FRAME instead.
This indicates that the (encoded) buffer marked as such contains the data for a key frame.
Constant Value: 1 (0x00000001)
CONFIGURE_FLAG_DETACHED_SURFACE
public static final int CONFIGURE_FLAG_DETACHED_SURFACE
Configure the codec with a detached output surface.
This flag is only defined for a video decoder. MediaCodec configured with this flag will be in Surface mode even though the surface parameter is null.
See also:
Constant Value: 8 (0x00000008)
CONFIGURE_FLAG_ENCODE
public static final int CONFIGURE_FLAG_ENCODE
If this codec is to be used as an encoder, pass this flag.
Constant Value: 1 (0x00000001)
CONFIGURE_FLAG_USE_BLOCK_MODEL
public static final int CONFIGURE_FLAG_USE_BLOCK_MODEL
If this codec is to be used with LinearBlock and/or HardwareBuffer, pass this flag.
When this flag is set, the following APIs throw IncompatibleWithBlockModelException.
getInputBuffer(int)getInputImage(int)getInputBuffers()getOutputBuffer(int)getOutputImage(int)getOutputBuffers()queueInputBuffer(int, int, int, long, int)queueSecureInputBuffer(int, int, CryptoInfo, long, int)dequeueInputBuffer(long)dequeueOutputBuffer(BufferInfo, long)
Constant Value: 2 (0x00000002)
CONFIGURE_FLAG_USE_CRYPTO_ASYNC
public static final int CONFIGURE_FLAG_USE_CRYPTO_ASYNC
This flag should be used on a secure decoder only. MediaCodec configured with this
flag does decryption in a separate thread. The flag requires MediaCodec to operate
asynchronously and will throw CryptoException if any, in the onCryptoError()
callback. Applications should override the default implementation of
onCryptoError() and access the associated CryptoException.
CryptoException thrown will contain MediaCodec.CryptoInfo
This can be accessed using getCryptoInfo()
Constant Value: 4 (0x00000004)
CRYPTO_MODE_AES_CBC
public static final int CRYPTO_MODE_AES_CBC
Constant Value: 2 (0x00000002)
CRYPTO_MODE_AES_CTR
public static final int CRYPTO_MODE_AES_CTR
Constant Value: 1 (0x00000001)
CRYPTO_MODE_UNENCRYPTED
public static final int CRYPTO_MODE_UNENCRYPTED
Constant Value: 0 (0x00000000)
INFO_OUTPUT_BUFFERS_CHANGED
public static final int INFO_OUTPUT_BUFFERS_CHANGED
This constant was deprecated
in API level 21.
This return value can be ignored as getOutputBuffers() has been deprecated. Client should
request a current buffer using on of the get-buffer or
get-image methods each time one has been dequeued.
The output buffers have changed, the client must refer to the new
set of output buffers returned by getOutputBuffers() from
this point on.
Additionally, this event signals that the video scaling mode may have been reset to the default.
Constant Value: -3 (0xfffffffd)
INFO_OUTPUT_FORMAT_CHANGED
public static final int INFO_OUTPUT_FORMAT_CHANGED
The output format has changed, subsequent data will follow the new
format. getOutputFormat() returns the new format. Note, that
you can also use the new getOutputFormat(int) method to
get the format for a specific output buffer. This frees you from
having to track output format changes.
Constant Value: -2 (0xfffffffe)
INFO_TRY_AGAIN_LATER
public static final int INFO_TRY_AGAIN_LATER
If a non-negative timeout had been specified in the call
to dequeueOutputBuffer(BufferInfo, long), indicates that the call timed out.
Constant Value: -1 (0xffffffff)
PARAMETER_KEY_HDR10_PLUS_INFO
public static final String PARAMETER_KEY_HDR10_PLUS_INFO
Set the HDR10+ metadata on the next queued input frame. Provide a byte array of data that's conforming to the user_data_registered_itu_t_t35() syntax of SEI message for ST 2094-40.
For decoders:
When a decoder is configured for one of the HDR10+ profiles that uses
out-of-band metadata (such as MediaCodecInfo.CodecProfileLevel.VP9Profile2HDR10Plus or MediaCodecInfo.CodecProfileLevel.VP9Profile3HDR10Plus), this
parameter sets the HDR10+ metadata on the next input buffer queued
to the decoder. A decoder supporting these profiles must propagate
the metadata to the format of the output buffer corresponding to this
particular input buffer (under key MediaFormat#KEY_HDR10_PLUS_INFO).
The metadata should be applied to that output buffer and the buffers
following it (in display order), until the next output buffer (in
display order) upon which an HDR10+ metadata is set.
This parameter shouldn't be set if the decoder is not configured for
an HDR10+ profile that uses out-of-band metadata. In particular,
it shouldn't be set for HDR10+ profiles that uses in-band metadata
where the metadata is embedded in the input buffers, for example
MediaCodecInfo.CodecProfileLevel#HEVCProfileMain10HDR10Plus.
For encoders:
When an encoder is configured for one of the HDR10+ profiles and the
operates in byte buffer input mode (instead of surface input mode),
this parameter sets the HDR10+ metadata on the next input buffer queued
to the encoder. For the HDR10+ profiles that uses out-of-band metadata
(such as MediaCodecInfo.CodecProfileLevel#VP9Profile2HDR10Plus,
or MediaCodecInfo.CodecProfileLevel#VP9Profile3HDR10Plus),
the metadata must be propagated to the format of the output buffer
corresponding to this particular input buffer (under key MediaFormat.KEY_HDR10_PLUS_INFO). For the HDR10+ profiles that uses
in-band metadata (such as MediaCodecInfo.CodecProfileLevel.HEVCProfileMain10HDR10Plus), the
metadata info must be embedded in the corresponding output buffer itself.
This parameter shouldn't be set if the encoder is not configured for an HDR10+ profile, or if it's operating in surface input mode.
See also:
Constant Value: "hdr10-plus-info"
PARAMETER_KEY_LOW_LATENCY
public static final String PARAMETER_KEY_LOW_LATENCY
Enable/disable low latency decoding mode. When enabled, the decoder doesn't hold input and output data more than required by the codec standards. The value is an Integer object containing the value 1 to enable or the value 0 to disable.
Constant Value: "low-latency"
PARAMETER_KEY_OFFSET_TIME
public static final String PARAMETER_KEY_OFFSET_TIME
Specify an offset (in micro-second) to be added on top of the timestamps onward. A typical use case is to apply an adjust to the timestamps after a period of pause by the user. This parameter can only be used on an encoder in "surface-input" mode. The value is a long int, indicating the timestamp offset to be applied.
See also:
Constant Value: "time-offset-us"
PARAMETER_KEY_QP_OFFSET_MAP
public static final String PARAMETER_KEY_QP_OFFSET_MAP
Set the region of interest as QpOffset-Map on the next queued input frame.
The associated value is a byte array containing quantization parameter (QP) offsets in
raster scan order for the entire frame at 16x16 granularity. The size of the byte array
shall be ((frame_width + 15) / 16) * ((frame_height + 15) / 16), where frame_width and
frame_height correspond to width and height configured using MediaFormat#KEY_WIDTH
and MediaFormat#KEY_HEIGHT keys respectively. During encoding, if the coding unit
size is larger than 16x16, then the qpOffset information of all 16x16 blocks that
encompass the coding unit is combined and used. The QP of target block will be calculated
as 'frameQP + offsetQP'. If the result exceeds minQP or maxQP configured then the value
will be clamped. Negative offset results in blocks encoded at lower QP than frame QP and
positive offsets will result in encoding blocks at higher QP than frame QP. If the areas
of negative QP and positive QP are chosen wisely, the overall viewing experience can be
improved.
If byte array size is too small than the expected size, components may ignore the configuration silently. If the byte array exceeds the expected size, components shall use the initial portion and ignore the rest.
The scope of this key is throughout the encoding session until it is reconfigured during running state.
See also:
Constant Value: "qp-offset-map"
PARAMETER_KEY_QP_OFFSET_RECTS
public static final String PARAMETER_KEY_QP_OFFSET_RECTS
Set the region of interest as QpOffset-Rects on the next queued input frame.
The associated value is a String in the format "Top1,Left1-Bottom1,Right1=Offset1;Top2, Left2-Bottom2,Right2=Offset2;...". Co-ordinates (Top, Left), (Top, Right), (Bottom, Left) and (Bottom, Right) form the vertices of bounding box of region of interest in pixels. Pixel (0, 0) points to the top-left corner of the frame. Offset is the suggested quantization parameter (QP) offset of the blocks in the bounding box. The bounding box will get stretched outwards to align to LCU boundaries during encoding. The Qp Offset is integral and shall be in the range [-128, 127]. The QP of target block will be calculated as frameQP + offsetQP. If the result exceeds minQP or maxQP configured then the value will be clamped. Negative offset results in blocks encoded at lower QP than frame QP and positive offsets will result in blocks encoded at higher QP than frame QP. If the areas of negative QP and positive QP are chosen wisely, the overall viewing experience can be improved.
If Roi rect is not valid that is bounding box width is < 0 or bounding box height is < 0, components may ignore the configuration silently. If Roi rect extends outside frame boundaries, then rect shall be clamped to the frame boundaries.
The scope of this key is throughout the encoding session until it is reconfigured during running state.
The maximum number of contours (rectangles) that can be specified for a given input frame is device specific. Implementations will drop/ignore the rectangles that are beyond their supported limit. Hence it is preferable to place the rects in descending order of importance. Transitively, if the bounding boxes overlap, then the most preferred rectangle's qp offset (earlier rectangle qp offset) will be used to quantize the block.
See also:
Constant Value: "qp-offset-rects"
PARAMETER_KEY_REQUEST_SYNC_FRAME
public static final String PARAMETER_KEY_REQUEST_SYNC_FRAME
Request that the encoder produce a sync frame "soon". Provide an Integer with the value 0.
See also:
Constant Value: "request-sync"
PARAMETER_KEY_SUSPEND
public static final String PARAMETER_KEY_SUSPEND
Temporarily suspend/resume encoding of input data. While suspended input data is effectively discarded instead of being fed into the encoder. This parameter really only makes sense to use with an encoder in "surface-input" mode, as the client code has no control over the input-side of the encoder in that case. The value is an Integer object containing the value 1 to suspend or the value 0 to resume.
See also:
Constant Value: "drop-input-frames"
PARAMETER_KEY_SUSPEND_TIME
public static final String PARAMETER_KEY_SUSPEND_TIME
When PARAMETER_KEY_SUSPEND is present, the client can also
optionally use this key to specify the timestamp (in micro-second)
at which the suspend/resume operation takes effect.
Note that the specified timestamp must be greater than or equal to the
timestamp of any previously queued suspend/resume operations.
The value is a long int, indicating the timestamp to suspend/resume.
See also:
Constant Value: "drop-start-time-us"
PARAMETER_KEY_TUNNEL_PEEK
public static final String PARAMETER_KEY_TUNNEL_PEEK
Control video peek of the first frame when a codec is configured for tunnel mode with
MediaFormat#KEY_AUDIO_SESSION_ID while the AudioTrack is paused.
When disabled (1) after a flush() or start(), (2) while the corresponding
AudioTrack is paused and (3) before any buffers are queued, the first frame is not to
be rendered until either this parameter is enabled or the corresponding AudioTrack
has begun playback. Once the frame is decoded and ready to be rendered,
OnFirstTunnelFrameReadyListener#onFirstTunnelFrameReady is called but the frame is
not rendered. The surface continues to show the previously-rendered content, or black if the
surface is new. A subsequent call to AudioTrack#play renders this frame and triggers
a callback to OnFrameRenderedListener#onFrameRendered, and video playback begins.
Note: To clear any previously rendered content and show black, configure the
MediaCodec with KEY_PUSH_BLANK_BUFFERS_ON_STOP(1), and call stop() before
pushing new video frames to the codec.
When enabled (1) after a flush() or start() and (2) while the corresponding
AudioTrack is paused, the first frame is rendered as soon as it is decoded, or
immediately, if it has already been decoded. If not already decoded, when the frame is
decoded and ready to be rendered,
OnFirstTunnelFrameReadyListener#onFirstTunnelFrameReady is called. The frame is then
immediately rendered and OnFrameRenderedListener#onFrameRendered is subsequently
called.
The value is an Integer object containing the value 1 to enable or the value 0 to disable.
The default for this parameter is enabled. Once a frame has been rendered, changing
this parameter has no effect until a subsequent flush() or
stop()/start().
See also:
Constant Value: "tunnel-peek"
PARAMETER_KEY_VIDEO_BITRATE
public static final String PARAMETER_KEY_VIDEO_BITRATE
Change a video encoder's target bitrate on the fly. The value is an Integer object containing the new bitrate in bps.
See also:
Constant Value: "video-bitrate"
VIDEO_SCALING_MODE_SCALE_TO_FIT
public static final int VIDEO_SCALING_MODE_SCALE_TO_FIT
The content is scaled to the surface dimensions
Constant Value: 1 (0x00000001)
VIDEO_SCALING_MODE_SCALE_TO_FIT_WITH_CROPPING
public static final int VIDEO_SCALING_MODE_SCALE_TO_FIT_WITH_CROPPING
The content is scaled, maintaining its aspect ratio, the whole surface area is used, content may be cropped.
This mode is only suitable for content with 1:1 pixel aspect ratio as you cannot
configure the pixel aspect ratio for a Surface.
As of Build.VERSION_CODES.N release, this mode may not work if
the video is rotated by 90 or 270 degrees.
Constant Value: 2 (0x00000002)
Public methods
configure
public void configure (MediaFormat format, Surface surface, MediaCrypto crypto, int flags)
Configures a component.
| Parameters | |
|---|---|
format |
MediaFormat: The format of the input data (decoder) or the desired
format of the output data (encoder). Passing null
as format is equivalent to passing an
an empty mediaformat. |
surface |
Surface: Specify a surface on which to render the output of this
decoder. Pass null as surface if the
codec does not generate raw video output (e.g. not a video
decoder) and/or if you want to configure the codec for
ByteBuffer output. |
crypto |
MediaCrypto: Specify a crypto object to facilitate secure decryption
of the media data. Pass null as crypto for
non-secure codecs.
Please note that MediaCodec does NOT take ownership
of the MediaCrypto object; it is the application's
responsibility to properly cleanup the MediaCrypto object
when not in use. |
flags |
int: Specify CONFIGURE_FLAG_ENCODE to configure the
component as an encoder.
Value is either 0 or a combination of CONFIGURE_FLAG_ENCODE, CONFIGURE_FLAG_USE_BLOCK_MODEL, and CONFIGURE_FLAG_USE_CRYPTO_ASYNC |
| Throws | |
|---|---|
IllegalArgumentException |
if the surface has been released (or is invalid),
or the format is unacceptable (e.g. missing a mandatory key),
or the flags are not set properly
(e.g. missing CONFIGURE_FLAG_ENCODE for an encoder). |
IllegalStateException |
if not in the Uninitialized state. |
MediaCodec.CryptoException |
upon DRM error. |
MediaCodec.CodecException |
upon codec error. |
configure
public void configure (MediaFormat format, Surface surface, int flags, MediaDescrambler descrambler)
Configure a component to be used with a descrambler.
| Parameters | |
|---|---|
format |
MediaFormat: The format of the input data (decoder) or the desired
format of the output data (encoder). Passing null
as format is equivalent to passing an
an empty mediaformat. |
surface |
Surface: Specify a surface on which to render the output of this
decoder. Pass null as surface if the
codec does not generate raw video output (e.g. not a video
decoder) and/or if you want to configure the codec for
ByteBuffer output. |
flags |
int: Specify CONFIGURE_FLAG_ENCODE to configure the
component as an encoder.
Value is either 0 or a combination of CONFIGURE_FLAG_ENCODE, CONFIGURE_FLAG_USE_BLOCK_MODEL, and CONFIGURE_FLAG_USE_CRYPTO_ASYNC |
descrambler |
MediaDescrambler: Specify a descrambler object to facilitate secure
descrambling of the media data, or null for non-secure codecs. |
| Throws | |
|---|---|
IllegalArgumentException |
if the surface has been released (or is invalid),
or the format is unacceptable (e.g. missing a mandatory key),
or the flags are not set properly
(e.g. missing CONFIGURE_FLAG_ENCODE for an encoder). |
IllegalStateException |
if not in the Uninitialized state. |
MediaCodec.CryptoException |
upon DRM error. |
MediaCodec.CodecException |
upon codec error. |
createByCodecName
public static MediaCodec createByCodecName (String name)
If you know the exact name of the component you want to instantiate
use this method to instantiate it. Use with caution.
Likely to be used with information obtained from MediaCodecList
| Parameters | |
|---|---|
name |
String: The name of the codec to be instantiated.
This value cannot be null. |
| Returns | |
|---|---|
MediaCodec |
This value cannot be null. |
| Throws | |
|---|---|
IOException |
if the codec cannot be created. |
IllegalArgumentException |
if name is not valid. |
NullPointerException |
if name is null. |
createDecoderByType
public static MediaCodec createDecoderByType (String type)
Instantiate the preferred decoder supporting input data of the given mime type. The following is a partial list of defined mime types and their semantics:
- "video/x-vnd.on2.vp8" - VP8 video (i.e. video in .webm)
- "video/x-vnd.on2.vp9" - VP9 video (i.e. video in .webm)
- "video/avc" - H.264/AVC video
- "video/hevc" - H.265/HEVC video
- "video/mp4v-es" - MPEG4 video
- "video/3gpp" - H.263 video
- "audio/3gpp" - AMR narrowband audio
- "audio/amr-wb" - AMR wideband audio
- "audio/mpeg" - MPEG1/2 audio layer III
- "audio/mp4a-latm" - AAC audio (note, this is raw AAC packets, not packaged in LATM!)
- "audio/vorbis" - vorbis audio
- "audio/g711-alaw" - G.711 alaw audio
- "audio/g711-mlaw" - G.711 ulaw audio
MediaCodecList#findDecoderForFormat
and createByCodecName(String) to ensure that the resulting codec can handle a
given format.
| Parameters | |
|---|---|
type |
String: The mime type of the input data.
This value cannot be null. |
| Returns | |
|---|---|
MediaCodec |
This value cannot be null. |
| Throws | |
|---|---|
IOException |
if the codec cannot be created. |
IllegalArgumentException |
if type is not a valid mime type. |
NullPointerException |
if type is null. |
createEncoderByType
public static MediaCodec createEncoderByType (String type)
Instantiate the preferred encoder supporting output data of the given mime type.
Note: It is preferred to use MediaCodecList#findEncoderForFormat
and createByCodecName(String) to ensure that the resulting codec can handle a
given format.
| Parameters | |
|---|---|
type |
String: The desired mime type of the output data.
This value cannot be null. |
| Returns | |
|---|---|
MediaCodec |
This value cannot be null. |
| Throws | |
|---|---|
IOException |
if the codec cannot be created. |
IllegalArgumentException |
if type is not a valid mime type. |
NullPointerException |
if type is null. |
createInputSurface
public Surface createInputSurface ()
Requests a Surface to use as the input to an encoder, in place of input buffers. This
may only be called after configure(MediaFormat, Surface, MediaCrypto, int) and before start().
The application is responsible for calling release() on the Surface when done.
The Surface must be rendered with a hardware-accelerated API, such as OpenGL ES.
Surface.lockCanvas(android.graphics.Rect) may fail or produce
unexpected results.
| Returns | |
|---|---|
Surface |
This value cannot be null. |
| Throws | |
|---|---|
IllegalStateException |
if not in the Configured state. |
createPersistentInputSurface
public static Surface createPersistentInputSurface ()
Create a persistent input surface that can be used with codecs that normally have an input
surface, such as video encoders. A persistent input can be reused by subsequent
MediaCodec or MediaRecorder instances, but can only be used by at
most one codec or recorder instance concurrently.
The application is responsible for calling release() on the Surface when done.
| Returns | |
|---|---|
Surface |
an input surface that can be used with setInputSurface(Surface).
This value cannot be null. |
dequeueInputBuffer
public int dequeueInputBuffer (long timeoutUs)
Returns the index of an input buffer to be filled with valid data or -1 if no such buffer is currently available. This method will return immediately if timeoutUs == 0, wait indefinitely for the availability of an input buffer if timeoutUs < 0 or wait up to "timeoutUs" microseconds if timeoutUs > 0.
| Parameters | |
|---|---|
timeoutUs |
long: The timeout in microseconds, a negative timeout indicates "infinite". |
| Returns | |
|---|---|
int |
|
| Throws | |
|---|---|
IllegalStateException |
if not in the Executing state, or codec is configured in asynchronous mode. |
MediaCodec.CodecException |
upon codec error. |
dequeueOutputBuffer
public int dequeueOutputBuffer (MediaCodec.BufferInfo info, long timeoutUs)
Dequeue an output buffer, block at most "timeoutUs" microseconds. Returns the index of an output buffer that has been successfully decoded or one of the INFO_* constants.
| Parameters | |
|---|---|
info |
MediaCodec.BufferInfo: Will be filled with buffer meta data.
This value cannot be null. |
timeoutUs |
long: The timeout in microseconds, a negative timeout indicates "infinite". |
| Returns | |
|---|---|
int |
Value is INFO_TRY_AGAIN_LATER, INFO_OUTPUT_FORMAT_CHANGED, or INFO_OUTPUT_BUFFERS_CHANGED |
| Throws | |
|---|---|
IllegalStateException |
if not in the Executing state, or codec is configured in asynchronous mode. |
MediaCodec.CodecException |
upon codec error. |
detachOutputSurface
public void detachOutputSurface ()
Detach the current output surface of a codec.
Detaches the currently associated output Surface from the MediaCodec decoder. This allows the SurfaceView or other component holding the Surface to be safely destroyed or modified without affecting the decoder's operation. After calling this method (and after it returns), the decoder will enter detached-Surface mode and will no longer render output.
| Throws | |
|---|---|
IllegalStateException |
if the codec was not configured in surface mode or if the codec does not support detaching the output surface. |
See also:
flush
public void flush ()
Flush both input and output ports of the component.
Upon return, all indices previously returned in calls to dequeueInputBuffer and dequeueOutputBuffer — or obtained
via onInputBufferAvailable or
onOutputBufferAvailable callbacks — become
invalid, and all buffers are owned by the codec.
If the codec is configured in asynchronous mode, call start()
after flush has returned to resume codec operations. The codec
will not request input buffers until this has happened.
Note, however, that there may still be outstanding onOutputBufferAvailable
callbacks that were not handled prior to calling flush.
The indices returned via these callbacks also become invalid upon calling flush and
should be discarded.
If the codec is configured in synchronous mode, codec will resume
automatically if it is configured with an input surface. Otherwise, it
will resume when dequeueInputBuffer is called.
| Throws | |
|---|---|
IllegalStateException |
if not in the Executing state. |
MediaCodec.CodecException |
upon codec error. |
getCanonicalName
public String getCanonicalName ()
Retrieve the underlying codec name.
This method is similar to getName(), except that it returns the underlying component
name even if an alias was used to create this MediaCodec object by name,
| Returns | |
|---|---|
String |
This value cannot be null. |
| Throws | |
|---|---|
IllegalStateException |
if in the Released state. |
getCodecInfo
public MediaCodecInfo getCodecInfo ()
Get the codec info. If the codec was created by createDecoderByType or createEncoderByType, what component is chosen is not known beforehand, and thus the caller does not have the MediaCodecInfo.
| Returns | |
|---|---|
MediaCodecInfo |
This value cannot be null. |
| Throws | |
|---|---|
IllegalStateException |
if in the Released state. |
getInputBuffer
public ByteBuffer getInputBuffer (int index)
Returns a cleared, writable ByteBuffer
object for a dequeued input buffer index to contain the input data.
After calling this method any ByteBuffer or Image object
previously returned for the same input index MUST no longer
be used.
| Parameters | |
|---|---|
index |
int: The index of a client-owned input buffer previously
returned from a call to dequeueInputBuffer(long),
or received via an onInputBufferAvailable callback. |
| Returns | |
|---|---|
ByteBuffer |
the input buffer, or null if the index is not a dequeued input buffer, or if the codec is configured for surface input. |
| Throws | |
|---|---|
IllegalStateException |
if not in the Executing state. |
MediaCodec.CodecException |
upon codec error. |
getInputBuffers
public ByteBuffer[] getInputBuffers ()
This method was deprecated
in API level 21.
Use the new getInputBuffer(int) method instead
each time an input buffer is dequeued.
Note: As of API 21, dequeued input buffers are
automatically cleared.
Do not use this method if using an input surface.
Retrieve the set of input buffers. Call this after start() returns. After calling this method, any ByteBuffers previously returned by an earlier call to this method MUST no longer be used.
| Returns | |
|---|---|
ByteBuffer[] |
This value cannot be null. |
| Throws | |
|---|---|
IllegalStateException |
if not in the Executing state, or codec is configured in asynchronous mode. |
MediaCodec.CodecException |
upon codec error. |
getInputFormat
public MediaFormat getInputFormat ()
Call this after configure(MediaFormat, Surface, MediaCrypto, int) returns successfully to
get the input format accepted by the codec. Do this to
determine what optional configuration parameters were
supported by the codec.
| Returns | |
|---|---|
MediaFormat |
This value cannot be null. |
| Throws | |
|---|---|
IllegalStateException |
if not in the Executing or Configured state. |
MediaCodec.CodecException |
upon codec error. |
getInputImage
public Image getInputImage (int index)
Returns a writable Image object for a dequeued input buffer index to contain the raw input video frame. After calling this method any ByteBuffer or Image object previously returned for the same input index MUST no longer be used.
| Parameters | |
|---|---|
index |
int: The index of a client-owned input buffer previously
returned from a call to dequeueInputBuffer(long),
or received via an onInputBufferAvailable callback. |
| Returns | |
|---|---|
Image |
the input image, or null if the index is not a dequeued input buffer, or not a ByteBuffer that contains a raw image. |
| Throws | |
|---|---|
IllegalStateException |
if not in the Executing state. |
MediaCodec.CodecException |
upon codec error. |
getMetrics
public PersistableBundle getMetrics ()
Return Metrics data about the current codec instance.
| Returns | |
|---|---|
PersistableBundle |
a PersistableBundle containing the set of attributes and values
available for the media being handled by this instance of MediaCodec
The attributes are descibed in MetricsConstants.
Additional vendor-specific fields may also be present in
the return value. |
getName
public String getName ()
Retrieve the codec name.
If the codec was created by createDecoderByType or createEncoderByType, what component is
chosen is not known beforehand. This method returns the name of the codec that was
selected by the platform.
Note: Implementations may provide multiple aliases (codec
names) for the same underlying codec, any of which can be used to instantiate the same
underlying codec in MediaCodec#createByCodecName. This method returns the
name used to create the codec in this case.
| Returns | |
|---|---|
String |
This value cannot be null. |
| Throws | |
|---|---|
IllegalStateException |
if in the Released state. |
getOutputBuffer
public ByteBuffer getOutputBuffer (int index)
Returns a read-only ByteBuffer for a dequeued output buffer index. The position and limit of the returned buffer are set to the valid output data. After calling this method, any ByteBuffer or Image object previously returned for the same output index MUST no longer be used.
| Parameters | |
|---|---|
index |
int: The index of a client-owned output buffer previously
returned from a call to dequeueOutputBuffer(BufferInfo, long),
or received via an onOutputBufferAvailable callback. |
| Returns | |
|---|---|
ByteBuffer |
the output buffer, or null if the index is not a dequeued output buffer, or the codec is configured with an output surface. |
| Throws | |
|---|---|
IllegalStateException |
if not in the Executing state. |
MediaCodec.CodecException |
upon codec error. |
getOutputBuffers
public ByteBuffer[] getOutputBuffers ()
This method was deprecated
in API level 21.
Use the new getOutputBuffer(int) method instead
each time an output buffer is dequeued. This method is not
supported if codec is configured in asynchronous mode.
Note: As of API 21, the position and limit of output
buffers that are dequeued will be set to the valid data
range.
Do not use this method if using an output surface.
Retrieve the set of output buffers. Call this after start()
returns and whenever dequeueOutputBuffer signals an output
buffer change by returning INFO_OUTPUT_BUFFERS_CHANGED. After calling this method, any
ByteBuffers previously returned by an earlier call to this
method MUST no longer be used.
| Returns | |
|---|---|
ByteBuffer[] |
This value cannot be null. |
| Throws | |
|---|---|
IllegalStateException |
if not in the Executing state, or codec is configured in asynchronous mode. |
MediaCodec.CodecException |
upon codec error. |
getOutputFormat
public MediaFormat getOutputFormat (int index)
Returns the output format for a specific output buffer.
| Parameters | |
|---|---|
index |
int: The index of a client-owned input buffer previously
returned from a call to dequeueInputBuffer(long). |
| Returns | |
|---|---|
MediaFormat |
the format for the output buffer, or null if the index is not a dequeued output buffer. |
getOutputFormat
public MediaFormat getOutputFormat ()
Call this after dequeueOutputBuffer signals a format change by returning
INFO_OUTPUT_FORMAT_CHANGED.
You can also call this after configure(MediaFormat, Surface, MediaCrypto, int) returns
successfully to get the output format initially configured
for the codec. Do this to determine what optional
configuration parameters were supported by the codec.
| Returns | |
|---|---|
MediaFormat |
This value cannot be null. |
| Throws | |
|---|---|
IllegalStateException |
if not in the Executing or Configured state. |
MediaCodec.CodecException |
upon codec error. |
getOutputFrame
public MediaCodec.OutputFrame getOutputFrame (int index)
Returns an OutputFrame object.
| Parameters | |
|---|---|
index |
int: output buffer index from
Callback#onOutputBufferAvailable |
| Returns | |
|---|---|
MediaCodec.OutputFrame |
OutputFrame object describing the output buffer
This value cannot be null. |
| Throws | |
|---|---|
IllegalStateException |
if not using block model |
IllegalArgumentException |
if the output buffer is not available or the index is out of range |
getOutputImage
public Image getOutputImage (int index)
Returns a read-only Image object for a dequeued output buffer index that contains the raw video frame. After calling this method, any ByteBuffer or Image object previously returned for the same output index MUST no longer be used.
| Parameters | |
|---|---|
index |
int: The index of a client-owned output buffer previously
returned from a call to dequeueOutputBuffer(BufferInfo, long),
or received via an onOutputBufferAvailable callback. |
| Returns | |
|---|---|
Image |
the output image, or null if the index is not a dequeued output buffer, not a raw video frame, or if the codec was configured with an output surface. |
| Throws | |
|---|---|
IllegalStateException |
if not in the Executing state. |
MediaCodec.CodecException |
upon codec error. |
getParameterDescriptor
public MediaCodec.ParameterDescriptor getParameterDescriptor (String name)
Describe a parameter with the name.
This method can be called in any codec state except for released state.
| Parameters | |
|---|---|
name |
String: name of the parameter to describe, typically one from
getSupportedVendorParameters().
This value cannot be null. |
| Returns | |
|---|---|
MediaCodec.ParameterDescriptor |
ParameterDescriptor object that describes the parameter.
null if unrecognized / not able to describe. |
| Throws | |
|---|---|
IllegalStateException |
if in the Released state. |
getQueueRequest
public MediaCodec.QueueRequest getQueueRequest (int index)
Return a QueueRequest object for an input slot index.
| Parameters | |
|---|---|
index |
int: input slot index from
Callback#onInputBufferAvailable |
| Returns | |
|---|---|
MediaCodec.QueueRequest |
queue request object
This value cannot be null. |
| Throws | |
|---|---|
IllegalStateException |
if not using block model |
IllegalArgumentException |
if the input slot is not available or the index is out of range |
getSupportedVendorParameters
public List<String> getSupportedVendorParameters ()
Returns a list of vendor parameter names.
This method can be called in any codec state except for released state.
| Returns | |
|---|---|
List<String> |
a list containing supported vendor parameters; an empty
list if no vendor parameters are supported. The order of the
parameters is arbitrary.
This value cannot be null. |
| Throws | |
|---|---|
IllegalStateException |
if in the Released state. |
mapHardwareBuffer
public static Image mapHardwareBuffer (HardwareBuffer hardwareBuffer)
Map a HardwareBuffer object into Image, so that the content of the buffer is
accessible. Depending on the usage and pixel format of the hardware buffer, it may not be
mappable; this method returns null in that case.
| Parameters | |
|---|---|
hardwareBuffer |
HardwareBuffer: HardwareBuffer to map.
This value cannot be null. |
| Returns | |
|---|---|
Image |
Mapped Image object, or null if the buffer is not mappable. |
queueInputBuffer
public void queueInputBuffer (int index,
int offset,
int size,
long presentationTimeUs,
int flags)
After filling a range of the input buffer at the specified index
submit it to the component. Once an input buffer is queued to
the codec, it MUST NOT be used until it is later retrieved by
getInputBuffer(int) in response to a dequeueInputBuffer(long)
return value or a Callback#onInputBufferAvailable
callback.
Many decoders require the actual compressed data stream to be
preceded by "codec specific data", i.e. setup data used to initialize
the codec such as PPS/SPS in the case of AVC video or code tables
in the case of vorbis audio.
The class MediaExtractor provides codec
specific data as part of
the returned track format in entries named "csd-0", "csd-1" ...
These buffers can be submitted directly after start() or
flush() by specifying the flag BUFFER_FLAG_CODEC_CONFIG. However, if you configure the
codec with a MediaFormat containing these keys, they
will be automatically submitted by MediaCodec directly after
start. Therefore, the use of BUFFER_FLAG_CODEC_CONFIG flag is discouraged and is
recommended only for advanced users.
To indicate that this is the final piece of input data (or rather that
no more input data follows unless the decoder is subsequently flushed)
specify the flag BUFFER_FLAG_END_OF_STREAM.
Note: Prior to Build.VERSION_CODES.M,
presentationTimeUs was not propagated to the frame timestamp of (rendered)
Surface output buffers, and the resulting frame timestamp was undefined.
Use releaseOutputBuffer(int, long) to ensure a specific frame timestamp is set.
Similarly, since frame timestamps can be used by the destination surface for rendering
synchronization, care must be taken to normalize presentationTimeUs so as to not be
mistaken for a system time. (See SurfaceView specifics).
| Parameters | |
|---|---|
index |
int: The index of a client-owned input buffer previously returned
in a call to dequeueInputBuffer(long). |
offset |
int: The byte offset into the input buffer at which the data starts. |
size |
int: The number of bytes of valid input data. |
presentationTimeUs |
long: The presentation timestamp in microseconds for this
buffer. This is normally the media time at which this
buffer should be presented (rendered). When using an output
surface, this will be propagated as the timestamp for the frame (after
conversion to nanoseconds). |
flags |
int: A bitmask of flags
BUFFER_FLAG_CODEC_CONFIG and BUFFER_FLAG_END_OF_STREAM.
While not prohibited, most codecs do not use the
BUFFER_FLAG_KEY_FRAME flag for input buffers. |
| Throws | |
|---|---|
IllegalStateException |
if not in the Executing state. |
MediaCodec.CodecException |
upon codec error. |
MediaCodec.CryptoException |
if a crypto object has been specified in
configure(MediaFormat, Surface, MediaCrypto, int) |
queueInputBuffers
public void queueInputBuffers (int index,
ArrayDeque<MediaCodec.BufferInfo> bufferInfos)
Submit multiple access units to the codec along with multiple
MediaCodec.BufferInfo describing the contents of the buffer. This method
is supported only in asynchronous mode. While this method can be used for all codecs,
it is meant for buffer batching, which is only supported by codecs that advertise
FEATURE_MultipleFrames. Other codecs will not output large output buffers via
onOutputBuffersAvailable, and instead will output single-access-unit output via
onOutputBufferAvailable.
Output buffer size can be configured using the following MediaFormat keys.
MediaFormat#KEY_BUFFER_BATCH_MAX_OUTPUT_SIZE and
MediaFormat#KEY_BUFFER_BATCH_THRESHOLD_OUTPUT_SIZE.
Details for each access unit present in the buffer should be described using
MediaCodec.BufferInfo. Access units must be laid out contiguously (without any gaps)
and in order. Multiple access units in the output if present, will be available in
Callback#onOutputBuffersAvailable or Callback#onOutputBufferAvailable
in case of single-access-unit output or when output does not contain any buffers,
such as flags.
All other details for populating MediaCodec.BufferInfo is the same as described in
queueInputBuffer(int, int, int, long, int).
| Parameters | |
|---|---|
index |
int: The index of a client-owned input buffer previously returned
in a call to dequeueInputBuffer(long). |
bufferInfos |
ArrayDeque: ArrayDeque of MediaCodec.BufferInfo that describes the
contents in the buffer. The ArrayDeque and the BufferInfo objects provided
can be recycled by the caller for re-use.
This value cannot be null. |
| Throws | |
|---|---|
IllegalStateException |
if not in the Executing state or not in asynchronous mode. |
MediaCodec.CodecException |
upon codec error. |
IllegalArgumentException |
upon if bufferInfos is empty, contains null, or if the access units are not contiguous. |
MediaCodec.CryptoException |
if a crypto object has been specified in
configure(MediaFormat, Surface, MediaCrypto, int) |
queueSecureInputBuffer
public void queueSecureInputBuffer (int index,
int offset,
MediaCodec.CryptoInfo info,
long presentationTimeUs,
int flags)
Similar to queueInputBuffer but submits a buffer that is
potentially encrypted.
Check out further notes at queueInputBuffer.
| Parameters | |
|---|---|
index |
int: The index of a client-owned input buffer previously returned
in a call to dequeueInputBuffer(long). |
offset |
int: The byte offset into the input buffer at which the data starts. |
info |
MediaCodec.CryptoInfo: Metadata required to facilitate decryption, the object can be
reused immediately after this call returns.
This value cannot be null. |
presentationTimeUs |
long: The presentation timestamp in microseconds for this
buffer. This is normally the media time at which this
buffer should be presented (rendered). |
flags |
int: A bitmask of flags
BUFFER_FLAG_CODEC_CONFIG and BUFFER_FLAG_END_OF_STREAM.
While not prohibited, most codecs do not use the
BUFFER_FLAG_KEY_FRAME flag for input buffers. |
| Throws | |
|---|---|
IllegalStateException |
if not in the Executing state. |
MediaCodec.CodecException |
upon codec error. |
MediaCodec.CryptoException |
if an error occurs while attempting to decrypt the buffer. An error code associated with the exception helps identify the reason for the failure. |
queueSecureInputBuffers
public void queueSecureInputBuffers (int index,
ArrayDeque<MediaCodec.BufferInfo> bufferInfos,
ArrayDeque<MediaCodec.CryptoInfo> cryptoInfos)
Similar to queueInputBuffers but submits multiple access units
in a buffer that is potentially encrypted.
Check out further notes at queueInputBuffers.
| Parameters | |
|---|---|
index |
int: The index of a client-owned input buffer previously returned
in a call to dequeueInputBuffer(long). |
bufferInfos |
ArrayDeque: ArrayDeque of MediaCodec.BufferInfo that describes the
contents in the buffer. The ArrayDeque and the BufferInfo objects provided
can be recycled by the caller for re-use.
This value cannot be null. |
cryptoInfos |
ArrayDeque: ArrayDeque of MediaCodec.CryptoInfo objects to facilitate the
decryption of the contents. The ArrayDeque and the CryptoInfo objects
provided can be reused immediately after the call returns. These objects
should correspond to bufferInfo objects to ensure correct decryption.
This value cannot be null. |
| Throws | |
|---|---|
IllegalStateException |
if not in the Executing state or not in asynchronous mode. |
MediaCodec.CodecException |
upon codec error. |
IllegalArgumentException |
upon if bufferInfos is empty, contains null, or if the access units are not contiguous. |
MediaCodec.CryptoException |
if an error occurs while attempting to decrypt the buffer. An error code associated with the exception helps identify the reason for the failure. |
release
public void release ()
Free up resources used by the codec instance. Make sure you call this when you're done to free up any opened component instance instead of relying on the garbage collector to do this for you at some point in the future.
releaseOutputBuffer
public void releaseOutputBuffer (int index,
boolean render)
If you are done with a buffer, use this call to return the buffer to the codec
or to render it on the output surface. If you configured the codec with an
output surface, setting render to true will first send the buffer
to that output surface. The surface will release the buffer back to the codec once
it is no longer used/displayed.
Once an output buffer is released to the codec, it MUST NOT
be used until it is later retrieved by getOutputBuffer(int) in response
to a dequeueOutputBuffer(BufferInfo, long) return value or a
Callback#onOutputBufferAvailable callback.
| Parameters | |
|---|---|
index |
int: The index of a client-owned output buffer previously returned
from a call to dequeueOutputBuffer(BufferInfo, long). |
render |
boolean: If a valid surface was specified when configuring the codec,
passing true renders this output buffer to the surface. |
| Throws | |
|---|---|
IllegalStateException |
if not in the Executing state. |
MediaCodec.CodecException |
upon codec error. |
releaseOutputBuffer
public void releaseOutputBuffer (int index,
long renderTimestampNs)
If you are done with a buffer, use this call to update its surface timestamp and return it to the codec to render it on the output surface. If you have not specified an output surface when configuring this video codec, this call will simply return the buffer to the codec.
The timestamp may have special meaning depending on the destination surface.
| SurfaceView specifics |
|---|
If you render your buffer on a SurfaceView,
you can use the timestamp to render the buffer at a specific time (at the
VSYNC at or after the buffer timestamp). For this to work, the timestamp
needs to be reasonably close to the current System#nanoTime.
Currently, this is set as within one (1) second. A few notes:
|
getOutputBuffer(int) in response
to a dequeueOutputBuffer(BufferInfo, long) return value or a
Callback#onOutputBufferAvailable callback.
| Parameters | |
|---|---|
index |
int: The index of a client-owned output buffer previously returned
from a call to dequeueOutputBuffer(BufferInfo, long). |
renderTimestampNs |
long: The timestamp to associate with this buffer when
it is sent to the Surface. |
| Throws | |
|---|---|
IllegalStateException |
if not in the Executing state. |
MediaCodec.CodecException |
upon codec error. |
reset
public void reset ()
Returns the codec to its initial (Uninitialized) state.
Call this if an unrecoverable
error has occured to reset the codec to its initial state after creation.
| Throws | |
|---|---|
MediaCodec.CodecException |
if an unrecoverable error has occured and the codec could not be reset. |
IllegalStateException |
if in the Released state. |
setAudioPresentation
public void setAudioPresentation (AudioPresentation presentation)
Sets the audio presentation.
| Parameters | |
|---|---|
presentation |
AudioPresentation: see AudioPresentation. In particular, id should be set.
This value cannot be null. |
setCallback
public void setCallback (MediaCodec.Callback cb, Handler handler)
Sets an asynchronous callback for actionable MediaCodec events.
If the client intends to use the component in asynchronous mode,
a valid callback should be provided before configure(MediaFormat, Surface, MediaCrypto, int) is called.
When asynchronous callback is enabled, the client should not call
getInputBuffers(), getOutputBuffers(),
dequeueInputBuffer(long) or dequeueOutputBuffer(android.media.MediaCodec.BufferInfo, long).
Also, flush() behaves differently in asynchronous mode. After calling
flush, you must call start() to "resume" receiving input buffers,
even if an input surface was created.
| Parameters | |
|---|---|
cb |
MediaCodec.Callback: The callback that will run. Use null to clear a previously
set callback (before configure is called and run
in synchronous mode). |
handler |
Handler: Callbacks will happen on the handler's thread. If null,
callbacks are done on the default thread (the caller's thread or the
main thread.) |
setCallback
public void setCallback (MediaCodec.Callback cb)
Sets an asynchronous callback for actionable MediaCodec events on the default looper.
Same as setCallback(android.media.MediaCodec.Callback, android.os.Handler) with handler set to null.
| Parameters | |
|---|---|
cb |
MediaCodec.Callback: The callback that will run. Use null to clear a previously
set callback (before configure is called and run
in synchronous mode). |
See also:
setInputSurface
public void setInputSurface (Surface surface)
Configures the codec (e.g. encoder) to use a persistent input surface in place of input
buffers. This may only be called after configure(MediaFormat, Surface, MediaCrypto, int) and before start(), in
lieu of createInputSurface().
| Parameters | |
|---|---|
surface |
Surface: a persistent input surface created by createPersistentInputSurface()
This value cannot be null. |
| Throws | |
|---|---|
IllegalStateException |
if not in the Configured state or does not require an input surface. |
IllegalArgumentException |
if the surface was not created by
createPersistentInputSurface(). |
setOnFirstTunnelFrameReadyListener
public void setOnFirstTunnelFrameReadyListener (Handler handler, MediaCodec.OnFirstTunnelFrameReadyListener listener)
Registers a callback to be invoked when the first output frame has been decoded
and is ready to be rendered on a codec configured for tunnel mode with KEY_AUDIO_SESSION_ID.
| Parameters | |
|---|---|
handler |
Handler: the callback will be run on the handler's thread. If null, the callback will be run on the default thread, which is the looper from
which the codec was created, or a new thread if there was none. |
listener |
MediaCodec.OnFirstTunnelFrameReadyListener: the callback that will be run. If null, clears any registered
listener. |
setOnFrameRenderedListener
public void setOnFrameRenderedListener (MediaCodec.OnFrameRenderedListener listener, Handler handler)
Registers a callback to be invoked when an output frame is rendered on the output surface.
This method can be called in any codec state, but will only have an effect in the Executing state for codecs that render buffers to the output surface.
Note: This callback is for informational purposes only: to get precise render timing samples, and can be significantly delayed and batched. Some frames may have been rendered even if there was no callback generated.
| Parameters | |
|---|---|
listener |
MediaCodec.OnFrameRenderedListener: the callback that will be run
This value may be null. |
handler |
Handler: the callback will be run on the handler's thread. If null,
the callback will be run on the default thread, which is the looper
from which the codec was created, or a new thread if there was none. |
setOutputSurface
public void setOutputSurface (Surface surface)
Dynamically sets the output surface of a codec.
This can only be used if the codec was configured with an output surface. The new output surface should have a compatible usage type to the original output surface. E.g. codecs may not support switching from a SurfaceTexture (GPU readable) output to ImageReader (software readable) output.
| Parameters | |
|---|---|
surface |
Surface: the output surface to use. It must not be null. |
| Throws | |
|---|---|
IllegalStateException |
if the codec does not support setting the output surface in the current state. |
IllegalArgumentException |
if the new surface is not of a suitable type for the codec. |
setParameters
public void setParameters (Bundle params)
Communicate additional parameter changes to the component instance. Note: Some of these parameter changes may silently fail to apply.
| Parameters | |
|---|---|
params |
Bundle: The bundle of parameters to set.
This value may be null. |
| Throws | |
|---|---|
IllegalStateException |
if in the Released state. |
setVideoScalingMode
public void setVideoScalingMode (int mode)
If a surface has been specified in a previous call to configure(MediaFormat, Surface, MediaCrypto, int)
specifies the scaling mode to use. The default is "scale to fit".
The scaling mode may be reset to the default each time an
INFO_OUTPUT_BUFFERS_CHANGED event is received from the codec; therefore, the client
must call this method after every buffer change event (and before the first output buffer is
released for rendering) to ensure consistent scaling mode.
Since the INFO_OUTPUT_BUFFERS_CHANGED event is deprecated, this can also be done
after each INFO_OUTPUT_FORMAT_CHANGED event.
| Parameters | |
|---|---|
mode |
int: Value is VIDEO_SCALING_MODE_SCALE_TO_FIT, or VIDEO_SCALING_MODE_SCALE_TO_FIT_WITH_CROPPING |
| Throws | |
|---|---|
IllegalArgumentException |
if mode is not recognized. |
IllegalStateException |
if in the Released state. |
signalEndOfInputStream
public void signalEndOfInputStream ()
Signals end-of-stream on input. Equivalent to submitting an empty buffer with
BUFFER_FLAG_END_OF_STREAM set. This may only be used with
encoders receiving input from a Surface created by createInputSurface().
| Throws | |
|---|---|
IllegalStateException |
if not in the Executing state. |
MediaCodec.CodecException |
upon codec error. |
start
public void start ()
After successfully configuring the component, call start.
Call start also if the codec is configured in asynchronous mode,
and it has just been flushed, to resume requesting input buffers.
| Throws | |
|---|---|
IllegalStateException |
if not in the Configured state
or just after flush() for a codec that is configured
in asynchronous mode. |
MediaCodec.CodecException |
upon codec error. Note that some codec errors for start may be attributed to future method calls. |
stop
public void stop ()
Finish the decode/encode session, note that the codec instance
remains active and ready to be start()ed again.
To ensure that it is available to other client call release()
and don't just rely on garbage collection to eventually do this for you.
| Throws | |
|---|---|
IllegalStateException |
if in the Released state. |
subscribeToVendorParameters
public void subscribeToVendorParameters (List<String> names)
Subscribe to vendor parameters, so that these parameters will be present in
getOutputFormat() and changes to these parameters generate
output format change event.
Unrecognized parameter names or standard (non-vendor) parameter names will be ignored.
reset() also resets the list of subscribed parameters.
If a parameter in names is already subscribed, it will remain subscribed.
This method can be called in any codec state except for released state. When called in running state with newly subscribed parameters, it takes effect no later than the processing of the subsequently queued buffer. For the new parameters, the codec will generate output format change event.
Note that any vendor parameters set in a configure(MediaFormat, Surface, MediaCrypto, int) or
setParameters(Bundle) call are automatically subscribed.
See also INFO_OUTPUT_FORMAT_CHANGED or Callback#onOutputFormatChanged
for output format change events.
| Parameters | |
|---|---|
names |
List: names of the vendor parameters to subscribe. This may be an empty list,
and in that case this method will not change the list of subscribed parameters.
This value cannot be null. |
| Throws | |
|---|---|
IllegalStateException |
if in the Released state. |
unsubscribeFromVendorParameters
public void unsubscribeFromVendorParameters (List<String> names)
Unsubscribe from vendor parameters, so that these parameters will not be present in
getOutputFormat() and changes to these parameters no longer generate
output format change event.
Unrecognized parameter names, standard (non-vendor) parameter names will be ignored.
reset() also resets the list of subscribed parameters.
If a parameter in names is already unsubscribed, it will remain unsubscribed.
This method can be called in any codec state except for released state. When called in running state with newly unsubscribed parameters, it takes effect no later than the processing of the subsequently queued buffer. For the removed parameters, the codec will generate output format change event.
Note that any vendor parameters set in a configure(MediaFormat, Surface, MediaCrypto, int) or
setParameters(Bundle) call are automatically subscribed, and with this method
they can be unsubscribed.
See also INFO_OUTPUT_FORMAT_CHANGED or Callback#onOutputFormatChanged
for output format change events.
| Parameters | |
|---|---|
names |
List: names of the vendor parameters to unsubscribe. This may be an empty list,
and in that case this method will not change the list of subscribed parameters.
This value cannot be null. |
| Throws | |
|---|---|
IllegalStateException |
if in the Released state. |
Protected methods
finalize
protected void finalize ()
Called by the garbage collector on an object when garbage collection
determines that there are no more references to the object.
A subclass overrides the finalize method to dispose of
system resources or to perform other cleanup.
The general contract of finalize is that it is invoked
if and when the Java virtual
machine has determined that there is no longer any
means by which this object can be accessed by any thread that has
not yet died, except as a result of an action taken by the
finalization of some other object or class which is ready to be
finalized. The finalize method may take any action, including
making this object available again to other threads; the usual purpose
of finalize, however, is to perform cleanup actions before
the object is irrevocably discarded. For example, the finalize method
for an object that represents an input/output connection might perform
explicit I/O transactions to break the connection before the object is
permanently discarded.
The finalize method of class Object performs no
special action; it simply returns normally. Subclasses of
Object may override this definition.
The Java programming language does not guarantee which thread will
invoke the finalize method for any given object. It is
guaranteed, however, that the thread that invokes finalize will not
be holding any user-visible synchronization locks when finalize is
invoked. If an uncaught exception is thrown by the finalize method,
the exception is ignored and finalization of that object terminates.
After the finalize method has been invoked for an object, no
further action is taken until the Java virtual machine has again
determined that there is no longer any means by which this object can
be accessed by any thread that has not yet died, including possible
actions by other objects or classes which are ready to be finalized,
at which point the object may be discarded.
The finalize method is never invoked more than once by a Java
virtual machine for any given object.
Any exception thrown by the finalize method causes
the finalization of this object to be halted, but is otherwise
ignored.
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Last updated 2024-06-18 UTC.