Using Exoplayer

Transcript

1. Using Exoplayer Effie Barak (@CodingChick)
3. What is Exoplayer ...and why is everyone talking about it
4. Udemy's Story
5. Media Player Simple integration, no extensibility mediaPlayer.setDataSource(url); mediaPlayer.prepare(); mediaPlayer.start();
6. @Override public boolean onError(MediaPlayer mp, int what, int extra) { mediaPlayerError = true; if(what == -38) { //This exception just Happens for varios unexplainable reasons UdemyMediaPlayer.this.prepareAsync(); } return false; }
7. This beautiful state machine is a lie
8. Exoplayer Very extensible, but steeper implementation curve
9. Solves these problems • Open source, written in Java • Built on top of Media Codec • Handles HLS correctly
10. Extensible and/ or supports • Background playing • Subtitles • Variable playing speed • Variable resolutions
11. Exoplayer basics
12. Tips to get started: • ExoPlayer is written in Java. • The sample app is a good place to start. • The default implementaions are Good Implementaions.
13. 1st part The player player = ExoPlayer.Factory.newInstance( PlayerConstants.RENDERER_COUNT, MIN_BUFFER_MS, MIN_REBUFFER_MS); playerControl = new PlayerControl(player);
14. Adding state listeners public abstract class UdemyBaseExoplayer implements ExoPlayer.Listener, ChunkSampleSource.EventListener, HlsSampleSource.EventListener, DefaultBandwidthMeter.EventListener, MediaCodecVideoTrackRenderer.EventListener, MediaCodecAudioTrackRenderer.EventListener player.addListener(this);
15. 2nd part The Core
16. The journey of a Stream
17. Allocator allocator = new DefaultAllocator(BUFFER_SEGMENT_SIZE); Handler mainHandler = player.getMainHandler(); DefaultBandwidthMeter bandwidthMeter = new DefaultBandwidthMeter(mainHandler, null); DataSource dataSource = new DefaultUriDataSource( context, bandwidthMeter, Util.getUserAgent(mContext, Constants.UDEMY_NAME)); ExtractorSampleSource sampleSource = new ExtractorSampleSource(uri, dataSource, allocator, BUFFER_SEGMENT_COUNT * BUFFER_SEGMENT_SIZE, mainHandler, player, 0); MediaCodecVideoTrackRenderer videoRenderer = new MediaCodecVideoTrackRenderer(context, sampleSource, MediaCodecSelector.DEFAULT, MediaCodec.VIDEO_SCALING_MODE_SCALE_TO_FIT, 5000, mainHandler, player, 50); MediaCodecAudioTrackRenderer audioRenderer = new MediaCodecAudioTrackRenderer(sampleSource, MediaCodecSelector.DEFAULT, null, true, mainHandler, player, AudioCapabilities.getCapabilities(context), AudioManager.STREAM_MUSIC); TrackRenderer[] renderers = new TrackRenderer[PlayerConstants.RENDERER_COUNT]; renderers[PlayerConstants.TYPE_VIDEO] = videoRenderer; renderers[PlayerConstants.TYPE_AUDIO] = audioRenderer; player.onRenderers(renderers, bandwidthMeter);
18. // Allocator allocator = new DefaultAllocator(BUFFER_SEGMENT_SIZE); // Handler mainHandler = player.getMainHandler(); // DefaultBandwidthMeter bandwidthMeter = new DefaultBandwidthMeter(mainHandler, null); // DataSource dataSource = new DefaultUriDataSource(context, bandwidthMeter, // Util.getUserAgent(mContext, Constants.UDEMY_NAME)); ExtractorSampleSource sampleSource = new ExtractorSampleSource(uri, dataSource, allocator, BUFFER_SEGMENT_COUNT * BUFFER_SEGMENT_SIZE, mainHandler, player, 0); MediaCodecVideoTrackRenderer videoRenderer = new MediaCodecVideoTrackRenderer(context, sampleSource, MediaCodecSelector.DEFAULT, MediaCodec.VIDEO_SCALING_MODE_SCALE_TO_FIT, 5000, mainHandler, player, 50); MediaCodecAudioTrackRenderer audioRenderer = new MediaCodecAudioTrackRenderer(sampleSource, MediaCodecSelector.DEFAULT, null, true, mainHandler, player, AudioCapabilities.getCapabilities(context), AudioManager.STREAM_MUSIC); TrackRenderer[] renderers = new TrackRenderer[PlayerConstants.RENDERER_COUNT]; renderers[PlayerConstants.TYPE_VIDEO] = videoRenderer; renderers[PlayerConstants.TYPE_AUDIO] = audioRenderer; player.onRenderers(renderers, bandwidthMeter);
19. Build extractors DefaultUriDataSource uriDataSource = new DefaultUriDataSource (context, bandwidthMeter, userAgent); ExtractorSampleSource sampleSource = new ExtractorSampleSource (uri, uriDataSource, allocator, PlayerConstants.BUFFER_SEGMENT_COUNT * PlayerConstants.BUFFER_SEGMENT_SIZE);
20. Build renderers TrackRenderer[] renderers = new TrackRenderer[PlayerConstants.RENDERER_COUNT]; MediaCodecAudioTrackRenderer audioRenderer = new MediaCodecAudioTrackRenderer( sampleSource, MediaCodecSelector.DEFAULT, null, true, player.getMainHandler(), player, AudioCapabilities.getCapabilities(context), AudioManager.STREAM_MUSIC); renderers[PlayerConstants.TYPE_AUDIO] = audioRenderer;
21. Connect renderers to the player player.prepare(renderers);
22. Udemy customizations to basic structure • We decreased the buffer size after getting OOM exceptions on low end devices. public static final int BUFFER_SEGMENT_SIZE = 16 * 1024; // Original value was 64 * 1024 public static final int VIDEO_BUFFER_SEGMENTS = 50; // Original value was 200 public static final int AUDIO_BUFFER_SEGMENTS = 20; // Original value was 54 public static final int BUFFER_SEGMENT_COUNT = 64; // Original value was 256
23. Udemy customizations to basic structure • We decreased the buffer size after getting OOM exceptions on low end devices. • The ExtractorSampleSource gets a list of possible extractors to work with (mp3 and mp4 only) mp4Extractor = new Mp4Extractor(); mp3Extractor = new Mp3Extractor(); sampleSource = new ExtractorSampleSource(..., mp4Extractor, mp3Extractor);
24. !
25. HLS
27. HLS File
29. DefaultBandwidthMeter bandwidthMeter = new DefaultBandwidthMeter(); PtsTimestampAdjusterProvider timestampAdjusterProvider = new PtsTimestampAdjusterProvider(); HlsChunkSource chunkSource = new HlsChunkSource(..., uriDataSource, url,..., bandwidthMeter, timestampAdjusterProvider, HlsChunkSource.ADAPTIVE_MODE_SPLICE);
30. sampleSource = new HlsSampleSource(chunkSource, ...);
32. The good news HlsChunkSource chunkSource = new HlsChunkSource(..., HlsChunkSource.ADAPTIVE_MODE_NONE);
33. The bad news // The index in variants of the currently selected variant. private int selectedVariantIndex; public void getChunkOperation(...) { int nextVariantIndex; ... if (adaptiveMode == ADAPTIVE_MODE_NONE) { nextVariantIndex = selectedVariantIndex; switchingVariantSpliced = false; } else { ... } ...
34. !
35. Background Media Playing
36. Clear the surface by sending a message to ExoPlayer that sets the surface to null player.blockingSendMessage( videoRenderer, MediaCodecVideoTrackRenderer.MSG_SET_SURFACE, null);
37. Create a service to keep the app alive. <service android:name="com.udemy.android.player.exoplayer.UdemyExoplayerService" android:exported="true" android:label="@string/app_name" android:enabled="true"> <intent-filter> <action android:name="ccom.udemy.android.player.exoplayer.UdemyExoplayerService"> </action> </intent-filter> </service> Both the view and the service control the same instance of the player, stored globally.
38. When the app resumes set the surface again setPlayerSurface(surfaceView.getHolder().getSurface()); And in the player public void setSurface(Surface surface) { this.surface = surface; pushSurface(false); }
39. Subtitles • Support .srt • Don't crash the video in case of error • Support multiple formats such as UTF-8
40. Feed subtitles manually :(
41. public void displayExoplayerSubtitles( File file, final MediaController.MediaPlayerControl playerControl, final ViewGroup subtitleLayout, final Context context) { convertFileCaptionList(file, context); runnableCode = new Runnable() { @Override public void run() { displayForPosition(playerControl.getCurrentPosition(), subtitleLayout, context); handler.postDelayed(runnableCode, 200); } }; handler.post(runnableCode); }
42. Subtitles conversion https://github.com/JDaren/subtitleConverter
43. Variable playback speeds
44. Video always follows Audio
45. Sonic library (The Java edition) https://github.com/waywardgeek/sonic/blob/master/ Sonic.java
46. Implementation
47. public class VariableSpeedAudioRenderer extends MediaCodecAudioTrackRenderer
48. Method to override private byte[] sonicInputBuffer; private byte[] sonicOutputBuffer; @Override protected void onOutputFormatChanged(final MediaFormat format) {
49. Method body // Two samples per frame * 2 to support audio speeds down to 0.5 final int bufferSizeBytes = SAMPLES_PER_CODEC_FRAME * 2 * 2 * channelCount; this.sonicInputBuffer = new byte[bufferSizeBytes]; this.sonicOutputBuffer = new byte[bufferSizeBytes]; this.sonic = new Sonic( format.getInteger(MediaFormat.KEY_SAMPLE_RATE), format.getInteger(MediaFormat.KEY_CHANNEL_COUNT)); this.lastInternalBuffer = ByteBuffer.wrap(sonicOutputBuffer, 0, 0); sonic.flushStream(); sonic.setSpeed(audioSpeed);
50. @Override protected boolean processOutputBuffer(..., final ByteBuffer buffer,...)
51. private ByteBuffer lastInternalBuffer; buffer.get(sonicInputBuffer, 0, bytesToRead); sonic.writeBytesToStream(sonicInputBuffer, bytesToRead); sonic.readBytesFromStream(sonicOutputBuffer, sonicOutputBuffer.length); return super.processOutputBuffer(..., lastInternalBuffer, ...);
52. Some optimization if (bufferIndex == lastSeenBufferIndex) { return super.processOutputBuffer(..., lastInternalBuffer, ..., bufferIndex, ...); } else { lastSeenBufferIndex = bufferIndex; }
53. To change the speed in the middle of consuming a buffer if (wasSpeedChanged) { sonic.flushStream(); sonic.setSpeed(audioSpeed); }
54. Thank you!