HeifWriter

class HeifWriter : AutoCloseable
kotlin.Any
   ↳ androidx.heifwriter.HeifWriter

This class writes one or more still images (of the same dimensions) into a heif file. It currently supports three input modes: INPUT_MODE_BUFFER, INPUT_MODE_SURFACE, or INPUT_MODE_BITMAP. The general sequence (in pseudo-code) to write a heif file using this class is as follows: 1) Construct the writer: HeifWriter heifwriter = new HeifWriter(...); 2) If using surface input mode, obtain the input surface: Surface surface = heifwriter.getInputSurface(); 3) Call start: heifwriter.start(); 4) Depending on the chosen input mode, add one or more images using one of these methods: heifwriter.addYuvBuffer(...); Or heifwriter.addBitmap(...); Or render to the previously obtained surface 5) Call stop: heifwriter.stop(...); 6) Close the writer: heifwriter.close(); Please refer to the documentations on individual methods for the exact usage.

Summary

Nested classes

Builder class for constructing a HeifWriter object from specified parameters.

Constants
static Int

The input mode where the client adds bitmaps.
static Int

The input mode where the client adds input buffers with YUV data.
static Int

The input mode where the client renders the images to an input Surface created by the writer.

Public methods
Unit
addBitmap(@NonNull bitmap: Bitmap)

Add one bitmap to the heif file.
Unit
addExifData(imageIndex: Int, @NonNull exifData: ByteArray, offset: Int, length: Int)

Add Exif data for the specified image.
Unit
addYuvBuffer(format: Int, @NonNull data: ByteArray)

Add one YUV buffer to the heif file.
Unit

Surface

Retrieves the input surface for encoding.
Unit

Set the timestamp (in nano seconds) of the last input frame to encode.
Unit

Start the heif writer.
Unit
stop(timeoutMs: Long)

Stop the heif writer synchronously.

Constants

INPUT_MODE_BITMAP

static val INPUT_MODE_BITMAP: Int

The input mode where the client adds bitmaps.

Value: 2

INPUT_MODE_BUFFER

static val INPUT_MODE_BUFFER: Int

The input mode where the client adds input buffers with YUV data.

Value: 0

INPUT_MODE_SURFACE

static val INPUT_MODE_SURFACE: Int

The input mode where the client renders the images to an input Surface created by the writer. The input surface operates in single buffer mode. As a result, for use case where camera directly outputs to the input surface, this mode will not work because camera framework requires multiple buffers to operate in a pipeline fashion.

Value: 1

Public methods

addBitmap

fun addBitmap(@NonNull bitmap: Bitmap): Unit

Add one bitmap to the heif file.

Parameters
bitmap Bitmap: the bitmap to be added to the file.
Exceptions
IllegalStateException if not started or not configured to use bitmap input.

addExifData

fun addExifData(
    imageIndex: Int, 
    @NonNull exifData: ByteArray, 
    offset: Int, 
    length: Int
): Unit

Add Exif data for the specified image. The data must be a valid Exif data block, starting with "Exif\0\0" followed by the TIFF header (See JEITA CP-3451C Section 4.5.2.)

Parameters
imageIndex Int: index of the image, must be a valid index for the max number of image specified by Builder#setMaxImages(int).
exifData ByteArray: byte buffer containing a Exif data block.
offset Int: offset of the Exif data block within exifData.
length Int: length of the Exif data block.

addYuvBuffer

fun addYuvBuffer(
    format: Int, 
    @NonNull data: ByteArray
): Unit

Add one YUV buffer to the heif file.

Parameters
format Int: The YUV format as defined in android.graphics.ImageFormat, currently only support YUV_420_888.
data ByteArray: byte array containing the YUV data. If the format has more than one planes, they must be concatenated.
Exceptions
IllegalStateException if not started or not configured to use buffer input.

close

fun close(): Unit

getInputSurface

@NonNull fun getInputSurface(): Surface

Retrieves the input surface for encoding.

Return
Surface: the input surface if configured to use surface input.
Exceptions
IllegalStateException if called after start or not configured to use surface input.

setInputEndOfStreamTimestamp

fun setInputEndOfStreamTimestamp(timestampNs: Long): Unit

Set the timestamp (in nano seconds) of the last input frame to encode. This call is only valid for surface input. Client can use this to stop the heif writer earlier before the maximum number of images are written. If not called, the writer will only stop when the maximum number of images are written.

Parameters
timestampNs Long: timestamp (in nano seconds) of the last frame that will be written to the heif file. Frames with timestamps larger than the specified value will not be written. However, if a frame already started encoding when this is set, all tiles within that frame will be encoded.
Exceptions
IllegalStateException if not started or not configured to use surface input.

start

fun start(): Unit

Start the heif writer. Can only be called once.

Exceptions
IllegalStateException if called more than once.

stop

fun stop(timeoutMs: Long): Unit

Stop the heif writer synchronously. Throws exception if the writer didn't finish writing successfully. Upon a success return: - For buffer and bitmap inputs, all images sent before stop will be written. - For surface input, images with timestamp on or before that specified in setInputEndOfStreamTimestamp(long) will be written. In case where setInputEndOfStreamTimestamp(long) was never called, stop will block until maximum number of images are received.

Parameters
timeoutMs Long: Maximum time (in microsec) to wait for the writer to complete, with zero indicating waiting indefinitely.
Exceptions
Exception if encountered error, in which case the output file may not be valid. In particular, TimeoutException is thrown when timed out, and is thrown when encountered codec error.