commit 005e9d0300fc326a076ec17b7fa6dd4f51568f55
author Andy Hung <hunga@google.com> Sun May 31 23:16:07 2015 -0700
committer Andy Hung <hunga@google.com> Wed Jun 03 22:42:14 2015 -0700
tree d9995f9aa6e174e73211e862526be8b13e5cec66
parent 85e48142f726770d3b65caa1f29d8b98f8d5db6b

NuPlayer: Allow audio drain to fill buffer when paused

If a pause lasts more than a few seconds, the audio device
enters standby.  When the audio device comes out of standby,
it typically requests a large amount of data to fill its buffers
(especially severe for deep buffer PCM mode).

To avoid a glitch, continue to fill the buffer (until no more data
can be written) when paused.

Also, we do not start the audio sink if we are paused to avoid
audio playback in video preview mode.

Bug: 19062223
Bug: 21198655
Change-Id: Ifb3f181d5e810283381b65f2af16a4c71df0b04f

media/libmediaplayerservice/nuplayer/NuPlayerRenderer.cpp

diff --git a/media/libmediaplayerservice/nuplayer/NuPlayerRenderer.cpp b/media/libmediaplayerservice/nuplayer/NuPlayerRenderer.cpp
index 5022439..f7e3117 100644
--- a/media/libmediaplayerservice/nuplayer/NuPlayerRenderer.cpp
+++ b/media/libmediaplayerservice/nuplayer/NuPlayerRenderer.cpp
@@ -623,8 +623,7 @@
 }
 
 void NuPlayer::Renderer::postDrainAudioQueue_l(int64_t delayUs) {
-    if (mDrainAudioQueuePending || mSyncQueues || mPaused
-            || mUseAudioCallback) {
+    if (mDrainAudioQueuePending || mSyncQueues || mUseAudioCallback) {
         return;
     }
 
@@ -800,6 +799,7 @@
     }
 #endif
 
+    uint32_t prevFramesWritten = mNumFramesWritten;
     while (!mAudioQueue.empty()) {
         QueueEntry *entry = &*mAudioQueue.begin();
 
@@ -898,7 +898,13 @@
     }
     mMediaClock->updateMaxTimeMedia(maxTimeMedia);
 
-    return !mAudioQueue.empty();
+    // calculate whether we need to reschedule another write.
+    bool reschedule = !mAudioQueue.empty()
+            && (!mPaused
+                || prevFramesWritten != mNumFramesWritten); // permit pause to fill buffers
+    //ALOGD("reschedule:%d  empty:%d  mPaused:%d  prevFramesWritten:%u  mNumFramesWritten:%u",
+    //        reschedule, mAudioQueue.empty(), mPaused, prevFramesWritten, mNumFramesWritten);
+    return reschedule;
 }
 
 int64_t NuPlayer::Renderer::getDurationUsIfPlayedAtSampleRate(uint32_t numFrames) {
@@ -1398,7 +1404,7 @@
 
     {
         Mutex::Autolock autoLock(mLock);
-        ++mAudioDrainGeneration;
+        // we do not increment audio drain generation so that we fill audio buffer during pause.
         ++mVideoDrainGeneration;
         prepareForMediaRenderingStart_l();
         mPaused = true;
@@ -1733,7 +1739,9 @@
             return err;
         }
         mCurrentPcmInfo = info;
-        mAudioSink->start();
+        if (!mPaused) { // for preview mode, don't start if paused
+            mAudioSink->start();
+        }
     }
     if (audioSinkChanged) {
         onAudioSinkChanged();