io.cine.android.streaming

Class TextureMovieEncoder

java.lang.Object

io.cine.android.streaming.TextureMovieEncoder

All Implemented Interfaces:

java.lang.Runnable

public class TextureMovieEncoder
extends java.lang.Object
implements java.lang.Runnable

Encode a movie from frames rendered from an external texture image.

The object wraps an encoder running on a dedicated thread. The various control messages may be sent from arbitrary threads (typically the app UI thread). The encoder thread manages both sides of the encoder (feeding and draining); the only external input is the GL texture.

The design is complicated slightly by the need to create an EGL context that shares state with a view that gets restarted if (say) the device orientation changes. When the view in question is a GLSurfaceView, we don't have full control over the EGL context creation on that side, so we have to bend a bit backwards here.

To use:

• create TextureMovieEncoder object
• create an EncoderConfig
• call TextureMovieEncoder#startRecording() with the config
• call TextureMovieEncoder#setTextureId() with the texture object that receives frames
• for each frame, after latching it with SurfaceTexture#updateTexImage(), call TextureMovieEncoder#frameAvailable().

TODO: tweak the API (esp. textureId) so it's less awkward for simple use cases.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	TextureMovieEncoder.EncoderConfig Encoder configuration.
static class	TextureMovieEncoder.EncoderHandler Handles encoder state change requests.

Field Summary

Fields

Modifier and Type	Field and Description
static int	MSG_ENCODER_SAVEFRAME

Constructor Summary

Constructors

Constructor and Description
TextureMovieEncoder()

Method Summary

Methods

Modifier and Type	Method and Description
void	frameAvailable(android.graphics.SurfaceTexture st) Tells the video recorder that a new frame is available.
TextureMovieEncoder.EncoderHandler	getHandler()
void	handleFrameAvailable(float[] transform, long timestampNanos) Handles notification of an available frame.
boolean	isRecording() Returns true if recording has been started.
void	run() Encoder thread entry point.
void	saveFrame(ScreenShot screenShot) This checks for the existence of an inputsurface and if it exists, simply calls the inputWindowSurface saveframe method.
void	setTextureId(int id) Tells the video recorder what texture name to use.
void	startRecording(TextureMovieEncoder.EncoderConfig config) Tells the video recorder to start recording.
void	stopRecording() Tells the video recorder to stop recording.
void	updateSharedContext(android.opengl.EGLContext sharedContext) Tells the video recorder to refresh its EGL surface.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

MSG_ENCODER_SAVEFRAME

public static final int MSG_ENCODER_SAVEFRAME

See Also:

Constant Field Values

Constructor Detail

TextureMovieEncoder

public TextureMovieEncoder()

Method Detail

startRecording

public void startRecording(TextureMovieEncoder.EncoderConfig config)

Tells the video recorder to start recording. (Call from non-encoder thread.)

Creates a new thread, which will create an encoder using the provided configuration.

Returns after the recorder thread has started and is ready to accept Messages. The encoder may not yet be fully configured.

stopRecording

public void stopRecording()

Tells the video recorder to stop recording. (Call from non-encoder thread.)

Returns immediately; the encoder/muxer may not yet be finished creating the movie.

TODO: have the encoder thread invoke a callback on the UI thread just before it shuts down so we can provide reasonable status UI (and let the caller know that movie encoding has completed).

isRecording

public boolean isRecording()

Returns true if recording has been started.

updateSharedContext

public void updateSharedContext(android.opengl.EGLContext sharedContext)

Tells the video recorder to refresh its EGL surface. (Call from non-encoder thread.)

frameAvailable

public void frameAvailable(android.graphics.SurfaceTexture st)

Tells the video recorder that a new frame is available. (Call from non-encoder thread.)

This function sends a message and returns immediately. This isn't sufficient -- we don't want the caller to latch a new frame until we're done with this one -- but we can get away with it so long as the input frame rate is reasonable and the encoder thread doesn't stall.

TODO: either block here until the texture has been rendered onto the encoder surface, or have a separate "block if still busy" method that the caller can execute immediately before it calls updateTexImage(). The latter is preferred because we don't want to stall the caller while this thread does work.

setTextureId

public void setTextureId(int id)

Tells the video recorder what texture name to use. This is the external texture that we're receiving camera previews in. (Call from non-encoder thread.)

TODO: do something less clumsy

run

public void run()

Encoder thread entry point. Establishes Looper/Handler and waits for messages.

Specified by:

run in interface java.lang.Runnable

See Also:

Thread.run()

saveFrame

public void saveFrame(ScreenShot screenShot)

This checks for the existence of an inputsurface and if it exists, simply calls the inputWindowSurface saveframe method.

Parameters:

screenShot -

handleFrameAvailable

public void handleFrameAvailable(float[] transform,
                        long timestampNanos)

Handles notification of an available frame.

The texture is rendered onto the encoder's input surface, along with a moving box (just because we can).

Parameters:

transform - The texture transform, from SurfaceTexture.

timestampNanos - The frame's timestamp, from SurfaceTexture.

getHandler

public TextureMovieEncoder.EncoderHandler getHandler()