AudioMixer uses downmix effect for multichannel content
In the AudioMixer structure associated with each track, add an object
that acts as the buffer provider when the track has more than two
channels of input in the mixer. This object, DownmixerBufferProvider,
gets audio from the actual buffer provider of the track, and applies
a downmix effect on it.
The downmix effect is created and configured when the track gets
created in AudioFlinger, which causes AudioMixer::getTrackName()
to be called with the new track's channel mask. It is released
when the track is disabled in the mixer.
Change-Id: I05281ed5f61bef663a8af7ca7d5ceac3517c82db
diff --git a/services/audioflinger/AudioFlinger.cpp b/services/audioflinger/AudioFlinger.cpp
index 9e6a6df..0ce1153 100644
--- a/services/audioflinger/AudioFlinger.cpp
+++ b/services/audioflinger/AudioFlinger.cpp
@@ -2639,9 +2639,15 @@
}
// getTrackName_l() must be called with ThreadBase::mLock held
-int AudioFlinger::MixerThread::getTrackName_l()
+int AudioFlinger::MixerThread::getTrackName_l(audio_channel_mask_t channelMask)
{
- return mAudioMixer->getTrackName();
+ int name = mAudioMixer->getTrackName();
+ if (name >= 0) {
+ mAudioMixer->setParameter(name,
+ AudioMixer::TRACK,
+ AudioMixer::CHANNEL_MASK, (void *)channelMask);
+ }
+ return name;
}
// deleteTrackName_l() must be called with ThreadBase::mLock held
@@ -2738,7 +2744,7 @@
readOutputParameters();
mAudioMixer = new AudioMixer(mFrameCount, mSampleRate);
for (size_t i = 0; i < mTracks.size() ; i++) {
- int name = getTrackName_l();
+ int name = getTrackName_l((audio_channel_mask_t)mTracks[i]->mChannelMask);
if (name < 0) break;
mTracks[i]->mName = name;
// limit track sample rate to 2 x new output sample rate
@@ -3066,7 +3072,7 @@
}
// getTrackName_l() must be called with ThreadBase::mLock held
-int AudioFlinger::DirectOutputThread::getTrackName_l()
+int AudioFlinger::DirectOutputThread::getTrackName_l(audio_channel_mask_t channelMask)
{
return 0;
}
@@ -3528,7 +3534,7 @@
// 16 bit because data is converted to 16 bit before being stored in buffer by AudioTrack
mCblk->frameSize = audio_is_linear_pcm(format) ? mChannelCount * sizeof(int16_t) : sizeof(uint8_t);
// to avoid leaking a track name, do not allocate one unless there is an mCblk
- mName = thread->getTrackName_l();
+ mName = thread->getTrackName_l((audio_channel_mask_t)channelMask);
if (mName < 0) {
ALOGE("no more track names available");
}