MediaCodec.LinearBlock


public static final class MediaCodec.LinearBlock
extends Object

java.lang.Object
   ↳ android.media.MediaCodec.LinearBlock


Section of memory that represents a linear block. Applications may acquire a block via LinearBlock#obtain and queue all or part of the block as an input buffer to a codec, or get a block allocated by codec as an output buffer from OutputFrame.

Summary

Public methods

static boolean isCodecCopyFreeCompatible(String[] codecNames)

Returns true if it is possible to allocate a linear block that can be passed to all listed codecs as input buffers without copying the content.

boolean isMappable()

Returns true if the buffer is mappable.

ByteBuffer map()

Map the memory and return the mapped region.

static MediaCodec.LinearBlock obtain(int capacity, String[] codecNames)

Obtain a linear block object no smaller than capacity.

void recycle()

Mark this block as ready to be recycled by the framework once it is no longer in use.

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

Public methods

isCodecCopyFreeCompatible

Added in API level 30
public static boolean isCodecCopyFreeCompatible (String[] codecNames)

Returns true if it is possible to allocate a linear block that can be passed to all listed codecs as input buffers without copying the content.

Note that even if this function returns true, obtain(int, String) may still throw due to invalid arguments or allocation failure.

Parameters
codecNames String: list of codecs that the client wants to use a linear block without copying. Null entries are ignored. This value cannot be null.

Returns
boolean

isMappable

Added in API level 30
public boolean isMappable ()

Returns true if the buffer is mappable.

Returns
boolean

Throws
IllegalStateException if invalid

map

Added in API level 30
public ByteBuffer map ()

Map the memory and return the mapped region.

The returned memory region becomes inaccessible after recycle(), or the buffer is queued to the codecs and not returned to the client yet.

Returns
ByteBuffer mapped memory region as ByteBuffer object This value cannot be null.

Throws
IllegalStateException if not mappable or invalid

obtain

Added in API level 30
public static MediaCodec.LinearBlock obtain (int capacity, 
                String[] codecNames)

Obtain a linear block object no smaller than capacity. If isCodecCopyFreeCompatible(String) with the same codecNames returned true, the returned LinearBlock object can be queued to the listed codecs without copying. The returned LinearBlock object is always read/write mappable.

Parameters
capacity int: requested capacity of the linear block in bytes

codecNames String: list of codecs that the client wants to use this linear block without copying. Null entries are ignored. This value cannot be null.

Returns
MediaCodec.LinearBlock a linear block object. This value may be null.

Throws
IllegalArgumentException if the capacity is invalid or codecNames contains invalid name
IOException if an error occurred while allocating a buffer

recycle

Added in API level 30
public void recycle ()

Mark this block as ready to be recycled by the framework once it is no longer in use. All operations to this object after this call will cause exceptions, as well as attempt to access the previously mapped memory region. Caller should clear all references to this object after this call.

To avoid excessive memory consumption, it is recommended that callers recycle buffers as soon as they no longer need the buffers

Throws
IllegalStateException if invalid

Protected methods

finalize

Added in API level 30
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.