Playback rate on MediaPlayer

Add support for modifying the playback rate of a MediaPlayer
 by altering the sample rate of its AudioTrack.
The playback rate is expressed in permille, where 1000 is the
 playback at normal speed.

Change-Id: I981d060ab32f7bae7a767e82c60c88ae635dceed

3 files changed, 7 insertions, 0 deletions

diff --git a/include/media/MediaPlayerInterface.h b/include/media/MediaPlayerInterface.h
index 7beb176..77c82b2 100644
--- a/include/media/MediaPlayerInterface.h
+++ b/include/media/MediaPlayerInterface.h
@@ -96,6 +96,8 @@ public:
         virtual void        flush() = 0;
         virtual void        pause() = 0;
         virtual void        close() = 0;
+
+        virtual status_t    setPlaybackRatePermille(int32_t rate) { return INVALID_OPERATION; }
     };
 
                         MediaPlayerBase() : mCookie(0), mNotify(0) {}
diff --git a/include/media/mediaplayer.h b/include/media/mediaplayer.h
index 00b7dd5..d0b87c8 100644
--- a/include/media/mediaplayer.h
+++ b/include/media/mediaplayer.h
@@ -145,6 +145,9 @@ enum media_parameter_keys {
     // audio track, or zero for error (e.g. no audio track) or unknown.
     KEY_PARAMETER_AUDIO_CHANNEL_COUNT = 1200,                   // get only
 
+    // Playback rate expressed in permille (1000 is normal speed), saved as int32_t, with negative
+    // values used for rewinding or reverse playback.
+    KEY_PARAMETER_PLAYBACK_RATE_PERMILLE = 1300,                // set only
 };
 
 // ----------------------------------------------------------------------------
diff --git a/include/media/stagefright/AudioPlayer.h b/include/media/stagefright/AudioPlayer.h
index 0b79324..70c47ae 100644
--- a/include/media/stagefright/AudioPlayer.h
+++ b/include/media/stagefright/AudioPlayer.h
@@ -64,6 +64,8 @@ public:
     bool isSeeking();
     bool reachedEOS(status_t *finalStatus);
 
+    status_t setPlaybackRatePermille(int32_t ratePermille);
+
 private:
     friend class VideoEditorAudioPlayer;
     sp<MediaSource> mSource;