Add channel mask in AudioSink

Add support for specifying a channel mask when opening an AudioSink.
  This parameter does not replace the channel count parameter in order
  to not have to duplicate the logic to derive a mask from the
  channel count everywhere an AudioSink is used without a known mask.

A mask of 0 (CHANNEL_MASK_USE_CHANNEL_ORDER) means a mask will
  be automatically derived from the number of channels.

Update existing AudioSink implementations to use the channel mask,
  and users of AudioSink to specify the mask if available, and
  CHANNEL_MASK_USE_CHANNEL_ORDER otherwise.

Change-Id: Ifa9bd259874816dbc25ead2b03ea52e873cff474

7 files changed, 42 insertions, 17 deletions

diff --git a/include/media/MediaPlayerInterface.h b/include/media/MediaPlayerInterface.h
index f7491d8..8168dff 100644
--- a/include/media/MediaPlayerInterface.h
+++ b/include/media/MediaPlayerInterface.h
@@ -60,6 +60,8 @@ enum player_type {
 #define DEFAULT_AUDIOSINK_BUFFERSIZE 1200
 #define DEFAULT_AUDIOSINK_SAMPLERATE 44100
 
+// when the channel mask isn't known, use the channel count to derive a mask in AudioSink::open()
+#define CHANNEL_MASK_USE_CHANNEL_ORDER 0
 
 // callback mechanism for passing messages to MediaPlayer object
 typedef void (*notify_callback_f)(void* cookie,
@@ -91,7 +93,7 @@ public:
         // If no callback is specified, use the "write" API below to submit
         // audio data.
         virtual status_t    open(
-                uint32_t sampleRate, int channelCount,
+                uint32_t sampleRate, int channelCount, audio_channel_mask_t channelMask,
                 audio_format_t format=AUDIO_FORMAT_PCM_16_BIT,
                 int bufferCount=DEFAULT_AUDIOSINK_BUFFERCOUNT,
                 AudioCallback cb = NULL,
diff --git a/include/media/stagefright/MetaData.h b/include/media/stagefright/MetaData.h
index 4cdee17..8b4b8ed 100644
--- a/include/media/stagefright/MetaData.h
+++ b/include/media/stagefright/MetaData.h
@@ -43,6 +43,7 @@ enum {
     kKeyStride            = 'strd',  // int32_t
     kKeySliceHeight       = 'slht',  // int32_t
     kKeyChannelCount      = '#chn',  // int32_t
+    kKeyChannelMask       = 'chnm',  // int32_t
     kKeySampleRate        = 'srte',  // int32_t (audio sampling rate Hz)
     kKeyFrameRate         = 'frmR',  // int32_t (video frame rate fps)
     kKeyBitRate           = 'brte',  // int32_t (bps)
diff --git a/media/libmediaplayerservice/MediaPlayerService.cpp b/media/libmediaplayerservice/MediaPlayerService.cpp
index 1e2abf0..bd3e07a 100644
--- a/media/libmediaplayerservice/MediaPlayerService.cpp
+++ b/media/libmediaplayerservice/MediaPlayerService.cpp
@@ -1458,7 +1458,8 @@ status_t MediaPlayerService::AudioOutput::getPosition(uint32_t *position)
 }
 
 status_t MediaPlayerService::AudioOutput::open(
-        uint32_t sampleRate, int channelCount, audio_format_t format, int bufferCount,
+        uint32_t sampleRate, int channelCount, audio_channel_mask_t channelMask,
+        audio_format_t format, int bufferCount,
         AudioCallback cb, void *cookie)
 {
     mCallback = cb;
@@ -1470,7 +1471,8 @@ status_t MediaPlayerService::AudioOutput::open(
         bufferCount = mMinBufferCount;
 
     }
-    ALOGV("open(%u, %d, %d, %d, %d)", sampleRate, channelCount, format, bufferCount,mSessionId);
+    ALOGV("open(%u, %d, 0x%x, %d, %d, %d)", sampleRate, channelCount, channelMask,
+            format, bufferCount, mSessionId);
     if (mTrack) close();
     int afSampleRate;
     int afFrameCount;
@@ -1485,13 +1487,21 @@ status_t MediaPlayerService::AudioOutput::open(
 
     frameCount = (sampleRate*afFrameCount*bufferCount)/afSampleRate;
 
+    if (channelMask == CHANNEL_MASK_USE_CHANNEL_ORDER) {
+        channelMask = audio_channel_mask_from_count(channelCount);
+        if (0 == channelMask) {
+            ALOGE("open() error, can\'t derive mask for %d audio channels", channelCount);
+            return NO_INIT;
+        }
+    }
+
     AudioTrack *t;
     if (mCallback != NULL) {
         t = new AudioTrack(
                 mStreamType,
                 sampleRate,
                 format,
-                (channelCount == 2) ? AUDIO_CHANNEL_OUT_STEREO : AUDIO_CHANNEL_OUT_MONO,
+                channelMask,
                 frameCount,
                 0 /* flags */,
                 CallbackWrapper,
@@ -1503,7 +1513,7 @@ status_t MediaPlayerService::AudioOutput::open(
                 mStreamType,
                 sampleRate,
                 format,
-                (channelCount == 2) ? AUDIO_CHANNEL_OUT_STEREO : AUDIO_CHANNEL_OUT_MONO,
+                channelMask,
                 frameCount,
                 0,
                 NULL,
@@ -1751,10 +1761,11 @@ bool CallbackThread::threadLoop() {
 ////////////////////////////////////////////////////////////////////////////////
 
 status_t MediaPlayerService::AudioCache::open(
-        uint32_t sampleRate, int channelCount, audio_format_t format, int bufferCount,
+        uint32_t sampleRate, int channelCount, audio_channel_mask_t channelMask,
+        audio_format_t format, int bufferCount,
         AudioCallback cb, void *cookie)
 {
-    ALOGV("open(%u, %d, %d, %d)", sampleRate, channelCount, format, bufferCount);
+    ALOGV("open(%u, %d, 0x%x, %d, %d)", sampleRate, channelCount, channelMask, format, bufferCount);
     if (mHeap->getHeapID() < 0) {
         return NO_INIT;
     }
diff --git a/media/libmediaplayerservice/MediaPlayerService.h b/media/libmediaplayerservice/MediaPlayerService.h
index 53847ed..681ecab 100644
--- a/media/libmediaplayerservice/MediaPlayerService.h
+++ b/media/libmediaplayerservice/MediaPlayerService.h
@@ -85,7 +85,7 @@ class MediaPlayerService : public BnMediaPlayerService
         virtual int             getSessionId();
 
         virtual status_t        open(
-                uint32_t sampleRate, int channelCount,
+                uint32_t sampleRate, int channelCount, audio_channel_mask_t channelMask,
                 audio_format_t format, int bufferCount,
                 AudioCallback cb, void *cookie);
 
@@ -145,8 +145,8 @@ class MediaPlayerService : public BnMediaPlayerService
         virtual int             getSessionId();
 
         virtual status_t        open(
-                uint32_t sampleRate, int channelCount, audio_format_t format,
-                int bufferCount = 1,
+                uint32_t sampleRate, int channelCount, audio_channel_mask_t channelMask,
+                audio_format_t format, int bufferCount = 1,
                 AudioCallback cb = NULL, void *cookie = NULL);
 
         virtual void            start();
diff --git a/media/libmediaplayerservice/MidiFile.cpp b/media/libmediaplayerservice/MidiFile.cpp
index 7cb8c29..8db5b9b 100644
--- a/media/libmediaplayerservice/MidiFile.cpp
+++ b/media/libmediaplayerservice/MidiFile.cpp
@@ -421,7 +421,8 @@ status_t MidiFile::setLooping(int loop)
 }
 
 status_t MidiFile::createOutputTrack() {
-    if (mAudioSink->open(pLibConfig->sampleRate, pLibConfig->numChannels, AUDIO_FORMAT_PCM_16_BIT, 2) != NO_ERROR) {
+    if (mAudioSink->open(pLibConfig->sampleRate, pLibConfig->numChannels,
+            CHANNEL_MASK_USE_CHANNEL_ORDER, AUDIO_FORMAT_PCM_16_BIT, 2) != NO_ERROR) {
         ALOGE("mAudioSink open failed");
         return ERROR_OPEN_FAILED;
     }
diff --git a/media/libmediaplayerservice/nuplayer/NuPlayer.cpp b/media/libmediaplayerservice/nuplayer/NuPlayer.cpp
index e618f67..526120a 100644
--- a/media/libmediaplayerservice/nuplayer/NuPlayer.cpp
+++ b/media/libmediaplayerservice/nuplayer/NuPlayer.cpp
@@ -336,6 +336,7 @@ void NuPlayer::onMessageReceived(const sp<AMessage> &msg) {
                     CHECK_EQ(mAudioSink->open(
                                 sampleRate,
                                 numChannels,
+                                CHANNEL_MASK_USE_CHANNEL_ORDER,
                                 AUDIO_FORMAT_PCM_16_BIT,
                                 8 /* bufferCount */),
                              (status_t)OK);
diff --git a/media/libstagefright/AudioPlayer.cpp b/media/libstagefright/AudioPlayer.cpp
index df27566..9427ef7 100644
--- a/media/libstagefright/AudioPlayer.cpp
+++ b/media/libstagefright/AudioPlayer.cpp
@@ -110,13 +110,18 @@ status_t AudioPlayer::start(bool sourceAlreadyStarted) {
     success = format->findInt32(kKeySampleRate, &mSampleRate);
     CHECK(success);
 
-    int32_t numChannels;
+    int32_t numChannels, channelMask;
     success = format->findInt32(kKeyChannelCount, &numChannels);
     CHECK(success);
 
+    if(!format->findInt32(kKeyChannelMask, &channelMask)) {
+        ALOGW("source format didn't specify channel mask, using channel order");
+        channelMask = CHANNEL_MASK_USE_CHANNEL_ORDER;
+    }
+
     if (mAudioSink.get() != NULL) {
         status_t err = mAudioSink->open(
-                mSampleRate, numChannels, AUDIO_FORMAT_PCM_16_BIT,
+                mSampleRate, numChannels, channelMask, AUDIO_FORMAT_PCM_16_BIT,
                 DEFAULT_AUDIOSINK_BUFFERCOUNT,
                 &AudioPlayer::AudioSinkCallback, this);
         if (err != OK) {
@@ -137,11 +142,15 @@ status_t AudioPlayer::start(bool sourceAlreadyStarted) {
 
         mAudioSink->start();
     } else {
+        // playing to an AudioTrack, set up mask if necessary
+        audio_channel_mask_t audioMask = channelMask == CHANNEL_MASK_USE_CHANNEL_ORDER ?
+                audio_channel_mask_from_count(numChannels) : channelMask;
+        if (0 == audioMask) {
+            return BAD_VALUE;
+        }
+
         mAudioTrack = new AudioTrack(
-                AUDIO_STREAM_MUSIC, mSampleRate, AUDIO_FORMAT_PCM_16_BIT,
-                (numChannels == 2)
-                    ? AUDIO_CHANNEL_OUT_STEREO
-                    : AUDIO_CHANNEL_OUT_MONO,
+                AUDIO_STREAM_MUSIC, mSampleRate, AUDIO_FORMAT_PCM_16_BIT, audioMask,
                 0, 0, &AudioCallback, this, 0);
 
         if ((err = mAudioTrack->initCheck()) != OK) {