Class VideoFrameReleaseHelper

  • public final class VideoFrameReleaseHelper
    extends Object
    Helps a video Renderer release frames to a Surface. The helper:
    • Adjusts frame release timestamps to achieve a smoother visual result. The release timestamps are smoothed, and aligned with the default display's vsync signal.
    • Adjusts the Surface frame rate to inform the underlying platform of a fixed frame rate, when there is one.
    • Constructor Detail

      • VideoFrameReleaseHelper

        public VideoFrameReleaseHelper​(@Nullable
                                       Context context)
        Constructs an instance.
        context - A context from which information about the default display can be retrieved.
    • Method Detail

      • onEnabled

        public void onEnabled()
        Called when the renderer is enabled.
      • onStarted

        public void onStarted()
        Called when the renderer is started.
      • onSurfaceChanged

        public void onSurfaceChanged​(@Nullable
                                     Surface surface)
        Called when the renderer changes which Surface it's rendering to renders to.
        surface - The new Surface, or null if the renderer does not have one.
      • onPositionReset

        public void onPositionReset()
        Called when the renderer's position is reset.
      • onPlaybackSpeed

        public void onPlaybackSpeed​(float playbackSpeed)
        Called when the renderer's playback speed changes.
        playbackSpeed - The factor by which playback is sped up.
      • onFormatChanged

        public void onFormatChanged​(float formatFrameRate)
        Called when the renderer's output format changes.
        formatFrameRate - The format's frame rate, or Format.NO_VALUE if unknown.
      • onNextFrame

        public void onNextFrame​(long framePresentationTimeUs)
        Called by the renderer for each frame, prior to it being skipped, dropped or rendered.
        framePresentationTimeUs - The frame presentation timestamp, in microseconds.
      • onStopped

        public void onStopped()
        Called when the renderer is stopped.
      • onDisabled

        public void onDisabled()
        Called when the renderer is disabled.
      • adjustReleaseTime

        public long adjustReleaseTime​(long releaseTimeNs)
        Adjusts the release timestamp for the next frame. This is the frame whose presentation timestamp was most recently passed to onNextFrame(long).

        This method may be called any number of times for each frame, including zero times (for skipped frames, or when rendering the first frame prior to playback starting), or more than once (if the caller wishes to give the helper the opportunity to refine a release time closer to when the frame needs to be released).

        releaseTimeNs - The frame's unadjusted release time, in nanoseconds and in the same time base as System.nanoTime().
        The adjusted frame release timestamp, in nanoseconds and in the same time base as System.nanoTime().