1 files changed, 42 insertions, 13 deletions

diff --git a/services/audioflinger/AudioFlinger.cpp b/services/audioflinger/AudioFlinger.cpp
index 69560e5..780c0d2 100644
--- a/services/audioflinger/AudioFlinger.cpp
+++ b/services/audioflinger/AudioFlinger.cpp
@@ -2066,7 +2066,21 @@ uint32_t AudioFlinger::MixerThread::prepareTracks_l(const SortedVector< wp<Track
         // The first time a track is added we wait
         // for all its buffers to be filled before processing it
         mAudioMixer->setActiveTrack(track->name());
-        if (cblk->framesReady() && track->isReady() &&
+        // make sure that we have enough frames to mix one full buffer.
+        // enforce this condition only once to enable draining the buffer in case the client
+        // app does not call stop() and relies on underrun to stop:
+        // hence the test on (track->mRetryCount >= kMaxTrackRetries) meaning the track was mixed
+        // during last round
+        uint32_t minFrames = 1;
+        if (!track->isStopped() && !track->isPausing() &&
+                (track->mRetryCount >= kMaxTrackRetries)) {
+            if (t->sampleRate() == (int)mSampleRate) {
+                minFrames = mFrameCount;
+            } else {
+                minFrames = (mFrameCount * t->sampleRate()) / mSampleRate + 1;
+            }
+        }
+        if ((cblk->framesReady() >= minFrames) && track->isReady() &&
                 !track->isPaused() && !track->isTerminated())
         {
             //LOGV("track %d u=%08x, s=%08x [OK] on thread %p", track->name(), cblk->user, cblk->server, this);
@@ -7014,11 +7028,17 @@ void AudioFlinger::EffectHandle::dump(char* buffer, size_t size)
 
 AudioFlinger::EffectChain::EffectChain(const wp<ThreadBase>& wThread,
                                         int sessionId)
-    : mThread(wThread), mSessionId(sessionId), mActiveTrackCnt(0), mTrackCnt(0),
+    : mThread(wThread), mSessionId(sessionId), mActiveTrackCnt(0), mTrackCnt(0), mTailBufferCount(0),
       mOwnInBuffer(false), mVolumeCtrlIdx(-1), mLeftVolume(UINT_MAX), mRightVolume(UINT_MAX),
       mNewLeftVolume(UINT_MAX), mNewRightVolume(UINT_MAX)
 {
     mStrategy = AudioSystem::getStrategyForStream(AUDIO_STREAM_MUSIC);
+    sp<ThreadBase> thread = mThread.promote();
+    if (thread == 0) {
+        return;
+    }
+    mMaxTailBuffers = ((kProcessTailDurationMs * thread->sampleRate()) / 1000) /
+                                    thread->frameCount();
 }
 
 AudioFlinger::EffectChain::~EffectChain()
@@ -7086,22 +7106,31 @@ void AudioFlinger::EffectChain::process_l()
     }
     bool isGlobalSession = (mSessionId == AUDIO_SESSION_OUTPUT_MIX) ||
             (mSessionId == AUDIO_SESSION_OUTPUT_STAGE);
-    bool tracksOnSession = false;
+    // always process effects unless no more tracks are on the session and the effect tail
+    // has been rendered
+    bool doProcess = true;
     if (!isGlobalSession) {
-        tracksOnSession = (trackCnt() != 0);
-    }
+        bool tracksOnSession = (trackCnt() != 0);
+
+        if (!tracksOnSession && mTailBufferCount == 0) {
+            doProcess = false;
+        }
 
-    // if no track is active, input buffer must be cleared here as the mixer process
-    // will not do it
-    if (tracksOnSession &&
-            activeTrackCnt() == 0) {
-        size_t numSamples = thread->frameCount() * thread->channelCount();
-        memset(mInBuffer, 0, numSamples * sizeof(int16_t));
+        if (activeTrackCnt() == 0) {
+            // if no track is active and the effect tail has not been rendered,
+            // the input buffer must be cleared here as the mixer process will not do it
+            if (tracksOnSession || mTailBufferCount > 0) {
+                size_t numSamples = thread->frameCount() * thread->channelCount();
+                memset(mInBuffer, 0, numSamples * sizeof(int16_t));
+                if (mTailBufferCount > 0) {
+                    mTailBufferCount--;
+                }
+            }
+        }
     }
 
     size_t size = mEffects.size();
-    // do not process effect if no track is present in same audio session
-    if (isGlobalSession || tracksOnSession) {
+    if (doProcess) {
         for (size_t i = 0; i < size; i++) {
             mEffects[i]->process();
         }