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, 29 insertions, 2 deletions

diff --git a/media/libmediaplayerservice/MediaPlayerService.cpp b/media/libmediaplayerservice/MediaPlayerService.cpp
index a0c20ae..4df7f3d 100644
--- a/media/libmediaplayerservice/MediaPlayerService.cpp
+++ b/media/libmediaplayerservice/MediaPlayerService.cpp
@@ -1265,6 +1265,8 @@ MediaPlayerService::AudioOutput::AudioOutput(int sessionId)
     mStreamType = AUDIO_STREAM_MUSIC;
     mLeftVolume = 1.0;
     mRightVolume = 1.0;
+    mPlaybackRatePermille = 1000;
+    mSampleRateHz = 0;
     mLatency = 0;
     mMsecsPerFrame = 0;
     mAuxEffectId = 0;
@@ -1402,10 +1404,15 @@ status_t MediaPlayerService::AudioOutput::open(
     ALOGV("setVolume");
     t->setVolume(mLeftVolume, mRightVolume);
 
-    mMsecsPerFrame = 1.e3 / (float) sampleRate;
+    mSampleRateHz = sampleRate;
+    mMsecsPerFrame = mPlaybackRatePermille / (float) sampleRate;
     mLatency = t->latency();
     mTrack = t;
 
+    status_t res = t->setSampleRate(mPlaybackRatePermille * mSampleRateHz / 1000);
+    if (res != NO_ERROR) {
+        return res;
+    }
     t->setAuxEffectSendLevel(mSendLevel);
     return t->attachAuxEffect(mAuxEffectId);;
 }
@@ -1469,6 +1476,22 @@ void MediaPlayerService::AudioOutput::setVolume(float left, float right)
     }
 }
 
+status_t MediaPlayerService::AudioOutput::setPlaybackRatePermille(int32_t ratePermille)
+{
+    ALOGV("setPlaybackRatePermille(%d)", ratePermille);
+    status_t res = NO_ERROR;
+    if (mTrack) {
+        res = mTrack->setSampleRate(ratePermille * mSampleRateHz / 1000);
+    } else {
+        res = NO_INIT;
+    }
+    mPlaybackRatePermille = ratePermille;
+    if (mSampleRateHz != 0) {
+        mMsecsPerFrame = mPlaybackRatePermille / (float) mSampleRateHz;
+    }
+    return res;
+}
+
 status_t MediaPlayerService::AudioOutput::setAuxEffectSendLevel(float level)
 {
     ALOGV("setAuxEffectSendLevel(%f)", level);
diff --git a/media/libmediaplayerservice/MediaPlayerService.h b/media/libmediaplayerservice/MediaPlayerService.h
index fa71d11..52af64d 100644
--- a/media/libmediaplayerservice/MediaPlayerService.h
+++ b/media/libmediaplayerservice/MediaPlayerService.h
@@ -95,6 +95,7 @@ class MediaPlayerService : public BnMediaPlayerService
         virtual void            close();
                 void            setAudioStreamType(audio_stream_type_t streamType) { mStreamType = streamType; }
                 void            setVolume(float left, float right);
+        virtual status_t        setPlaybackRatePermille(int32_t ratePermille);
                 status_t        setAuxEffectSendLevel(float level);
                 status_t        attachAuxEffect(int effectId);
         virtual status_t        dump(int fd, const Vector<String16>& args) const;
@@ -112,6 +113,8 @@ class MediaPlayerService : public BnMediaPlayerService
         audio_stream_type_t     mStreamType;
         float                   mLeftVolume;
         float                   mRightVolume;
+        int32_t                 mPlaybackRatePermille;
+        uint32_t                mSampleRateHz; // sample rate of the content, as set in open()
         float                   mMsecsPerFrame;
         uint32_t                mLatency;
         int                     mSessionId;
@@ -152,6 +155,7 @@ class MediaPlayerService : public BnMediaPlayerService
         virtual void            close() {}
                 void            setAudioStreamType(audio_stream_type_t streamType) {}
                 void            setVolume(float left, float right) {}
+        virtual status_t        setPlaybackRatePermille(int32_t ratePermille) { return INVALID_OPERATION; }
                 uint32_t        sampleRate() const { return mSampleRate; }
                 audio_format_t  format() const { return mFormat; }
                 size_t          size() const { return mSize; }
diff --git a/media/libmediaplayerservice/StagefrightPlayer.cpp b/media/libmediaplayerservice/StagefrightPlayer.cpp
index 6d7771a..052ebf0 100644
--- a/media/libmediaplayerservice/StagefrightPlayer.cpp
+++ b/media/libmediaplayerservice/StagefrightPlayer.cpp
@@ -176,7 +176,7 @@ void StagefrightPlayer::setAudioSink(const sp<AudioSink> &audioSink) {
 }
 
 status_t StagefrightPlayer::setParameter(int key, const Parcel &request) {
-    ALOGV("setParameter");
+    ALOGV("setParameter(key=%d)", key);
     return mPlayer->setParameter(key, request);
 }