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 @@
 #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 @@
         // 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 @@
     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::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 @@
         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 @@
 
     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 @@
                 mStreamType,
                 sampleRate,
                 format,
-                (channelCount == 2) ? AUDIO_CHANNEL_OUT_STEREO : AUDIO_CHANNEL_OUT_MONO,
+                channelMask,
                 frameCount,
                 0,
                 NULL,
@@ -1751,10 +1761,11 @@
 ////////////////////////////////////////////////////////////////////////////////
 
 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 @@
         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 @@
         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::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 @@
                     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 @@
     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 @@
 
         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) {