Streaming the Droid

Transcript

1. Streaming to the Droid
   David Gonzalez
   Android Software Craftsman
   

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2. Who is this
   guy?
   

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3. What is he going to
   talk about?
   

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5. Streaming protocols
   » Apple’s HTTP Live Streaming (HLS)
   » Adobe’s HTTP Dynamic Streaming (HDS)
   » Dynamic Adaptive Streaming over HTTP (aka MPEG-
   DASH)
   » Real Time Streaming Protocol (RTSP)
   

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6. HLS Support
   

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7. 2.3 Gingerbread
   No native support
   

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8. 3.0 Honeycomb
   HoneyWHAT?
   

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9. Solutions
   » Commercial: Adobe Prime Time, etc
   » Native: Custom native solution
   

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10. Let's talk about Native
    TextureView vs SurfaceView
    

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11. SurfaceView
    Creates a separate window
    Current VideoView is a SurfaceView
    

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12. TextureView
    behaves as a regular View.
    This key difference allows a TextureView to be moved,
    transformed, animated, etc
    

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13. Our approach
    /**
    * Displays a video file. The VideoView class
    * can load images from various sources (such as resources or content
    * providers), takes care of computing its measurement from the video so that
    * it can be used in any layout manager, and provides various display options
    * such as scaling and tinting.
    *
    * Note: VideoView does not retain its full state when going into the
    * background. In particular, it does not restore the current play state,
    * play position, selected tracks added via
    * {@link android.app.Activity#onSaveInstanceState} and
    * {@link android.app.Activity#onRestoreInstanceState}.
    * Also note that the audio session id (from {@link #getAudioSessionId}) may
    * change from its previously returned value when the VideoView is restored.
    */
    public class TextureVideoView extends android.view.TextureView implements Player {
    

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14. Preparing for playing
    mMediaPlayer.setDataSource(getContext(), mUri, mHeaders);
    mMediaPlayer.setSurface(new Surface(mSurfaceTexture));
    mMediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
    mMediaPlayer.setScreenOnWhilePlaying(true);
    mMediaPlayer.prepareAsync();
    // we don't set the target state here either, but preserve the target state that was there before.
    mCurrentState = STATE_PREPARING;
    

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16. OnPrepared Listener
    mMediaPlayer.setOnPreparedListener(mPreparedListener);
    private MediaPlayer.OnPreparedListener mPreparedListener =
    new MediaPlayer.OnPreparedListener() {
    @Override
    public void onPrepared(final MediaPlayer mp) {
    mCurrentState = STATE_PREPARED;
    mCanPause = true;
    mCanSeekBack = true;
    mCanSeekForward = true;
    if (mOnPreparedListener != null) {
    mOnPreparedListener.onPrepared(mMediaPlayer);
    }
    if (mConcertPlayerController != null) {
    mConcertPlayerController.setEnabled(true);
    }
    if (seekToPosition != 0) {
    seekTo(seekToPosition);
    }
    ...
    }
    };
    

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17. OnPrepared Listener
    videoSizeCalculator.setVideoSize(mp.getVideoWidth(), mp.getVideoHeight());
    if (videoSizeCalculator.hasASizeYet()) {
    // We didn't actually change the size (it was already at the size we need),
    // so we won't get a "surface changed" callback,
    // so start the video here instead of in the callback.
    if (mTargetState == STATE_PLAYING) {
    start();
    showMediaController();
    } else if (pausedAt(seekToPosition)) {
    showStickyMediaController();
    }
    } else {
    // We don't know the video size yet, but should start anyway.
    // The video size might be reported to us later.
    if (mTargetState == STATE_PLAYING) {
    start();
    

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18. OnErrorListener Listener
    mMediaPlayer.setOnErrorListener(mErrorListener);
    private OnErrorListener mErrorListener = new OnErrorListener() {
    @Override
    public boolean onError(final MediaPlayer mp, final int frameworkError, final int implError) {
    if (mCurrentState == STATE_ERROR) {
    return true;
    }
    mCurrentState = STATE_ERROR;
    mTargetState = STATE_ERROR;
    hideMediaController();
    if (allowPlayStateToHandle(frameworkError)) {
    return true;
    }
    if (allowErrorListenerToHandle(frameworkError, implError)) {
    return true;
    }
    handleError(frameworkError);
    return true;
    }
    };
    

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19. OnErrorListener Listener
    switch (what) {
    case -1004:
    errorMessage += "MEDIA_ERROR_IO";
    case -1007:
    errorMessage += "MEDIA_ERROR_MALFORMED";
    case 200:
    errorMessage += "MEDIA_ERROR_NOT_VALID_FOR_PROGRESSIVE_PLAYBACK";
    case 100:
    errorMessage += "MEDIA_ERROR_SERVER_DIED";
    case 1:
    errorMessage += "MEDIA_ERROR_UNKNOWN";
    case -1010:
    errorMessage += "MEDIA_ERROR_UNSUPPORTED";
    default:
    errorMessage += "MEDIA_ERROR_UNKNOWN";
    }
    

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20. OnErrorListener Listener
    switch (extra) {
    case 800:
    errorMessage += "MEDIA_INFO_BAD_INTERLEAVING";
    case 702:
    errorMessage += "MEDIA_INFO_BUFFERING_END";
    case 701:
    errorMessage += "MEDIA_INFO_METADATA_UPDATE";
    case 802:
    errorMessage += "MEDIA_INFO_METADATA_UPDATE";
    case 801:
    errorMessage += "MEDIA_INFO_NOT_SEEKABLE";
    case 1:
    errorMessage += "MEDIA_INFO_UNKNOWN";
    case 3:
    errorMessage += "MEDIA_INFO_VIDEO_RENDERING_START";
    case 700:
    errorMessage += "MEDIA_INFO_VIDEO_TRACK_LAGGING";
    case -110:
    errorMessage += "MEDIA_ERROR_TIMED_OUT";
    default:
    errorMessage += "MEDIA_INFO_UNKNOWN";
    }
    

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21. OnInfoListener Listener
    mMediaPlayer.setOnInfoListener(mInfoListener);
    private final OnInfoListener onInfoToPlayStateListener = new OnInfoListener() {
    @Override
    public boolean onInfo(final MediaPlayer mp, final int what, final int extra) {
    if (noPlayStateListener()) {
    return false;
    }
    if (MediaPlayer.MEDIA_INFO_VIDEO_RENDERING_START == what) {
    onPlayStateListener.onFirstVideoFrameRendered();
    onPlayStateListener.onPlay();
    }
    if (MediaPlayer.MEDIA_INFO_BUFFERING_START == what) {
    onPlayStateListener.onBuffer();
    }
    if (MediaPlayer.MEDIA_INFO_BUFFERING_END == what) {
    onPlayStateListener.onPlay();
    }
    return false;
    }
    }
    

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22. Custom listeners
    mMediaPlayer.setOnVideoSizeChangedListener(mSizeChangedListener);
    mMediaPlayer.setOnCompletionListener(mCompletionListener);
    mMediaPlayer.setOnBufferingUpdateListener(mBufferingUpdateListener);
    

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25. Custom Controller
    /**
    * Controller to manage syncing the ui models with the UI Controls and MediaPlayer.
    *
    * Note that the ui models have a narrow scope (i.e. chapter list, piece navigation),
    * their interaction is orchestrated by this controller.ø
    *
    * It's actually a view currently, as is the android MediaController.
    * (which is a bit odd and should be subject to change.)
    */
    public final class ConcertPlayerController extends FrameLayout implements
    VideoTouchRoot.OnTouchReceiver,
    TextureVideoView.VideoController,
    TextureVideoView.OnPlayStateListener {
    

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26. Custom Controller
    @Override
    protected void onCreate(final Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_play_concert);
    ...
    bindViews();
    }
    private void attachMediaController() {
    if (mMediaPlayer != null && mConcertPlayerController != null) {
    mConcertPlayerController.setMediaPlayer(this);
    View anchorView = this.getParent() instanceof View ? (View) this.getParent() : this;
    mConcertPlayerController.setAnchorView(anchorView);
    mConcertPlayerController.setEnabled(isInPlaybackState());
    }
    }
    

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27. System UI
    private void setSystemUiVisibility(final boolean visible) {
    // always use the full screen estate to avoid resizing flicker
    int newVis = View.SYSTEM_UI_FLAG_LAYOUT_STABLE |
    View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN |
    View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION;
    if (!visible) {
    newVis |= View.SYSTEM_UI_FLAG_LOW_PROFILE
    | View.SYSTEM_UI_FLAG_FULLSCREEN
    | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION;
    }
    final View decorView = getWindow().getDecorView();
    decorView.setSystemUiVisibility(newVis);
    decorView.setOnSystemUiVisibilityChangeListener(new View.OnSystemUiVisibilityChangeListener() {
    @Override
    public void onSystemUiVisibilityChange(final int visibility) {
    if ((visibility & View.SYSTEM_UI_FLAG_LOW_PROFILE) == 0) {
    //no low_profile flag means show controls
    concertPlayerController.show();
    }
    }
    });
    }
    

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31. Don't trust the
    device
    

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32. LESSONS LEARNED
    » Test on every possible device
    » Encrypted Video Streams are always a problem
    » Delay between Video / Audio
    » minSDK 14
    

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34. Further reading
    https://github.com/novoda/fenster
    https://github.com/google/grafika
    

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35. THANKS
    

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