commit 7a490e7ab39ef0b22baf24b03f2463c46dc068ed
author Andy Hung <hunga@google.com> Wed Mar 23 15:58:10 2016 -0700
committer Andy Hung <hunga@google.com> Mon Mar 28 17:22:50 2016 -0700
tree 067f8a45cc1e8e95e938caa96ea3d9d186607289
parent fdb90f355b269737fe48a2da0593b37d5c2b83c1

Read from proxy for PCM direct and offloaded track position

Bug: 27776737
Change-Id: I721bf2b4d46271bf84ad9fc29ff5c4ecd4759206

include/media/AudioTrack.h

diff --git a/include/media/AudioTrack.h b/include/media/AudioTrack.h
index 9e0e98b..bdd6372 100644
--- a/include/media/AudioTrack.h
+++ b/include/media/AudioTrack.h
@@ -830,6 +830,11 @@
             bool     isDirect_l() const
                 { return (mFlags & AUDIO_OUTPUT_FLAG_DIRECT) != 0; }
 
+            // pure pcm data is mixable (which excludes HW_AV_SYNC, with embedded timing)
+            bool     isPurePcmData_l() const
+                { return audio_is_linear_pcm(mFormat)
+                        && (mAttributes.flags & AUDIO_FLAG_HW_AV_SYNC) == 0; }
+
             // increment mPosition by the delta of mServer, and return new value of mPosition
             Modulo<uint32_t> updateAndGetPosition_l();
 

media/libmedia/AudioTrack.cpp

diff --git a/media/libmedia/AudioTrack.cpp b/media/libmedia/AudioTrack.cpp
index 3f4594d..34d23d5 100644
--- a/media/libmedia/AudioTrack.cpp
+++ b/media/libmedia/AudioTrack.cpp
@@ -1014,7 +1014,11 @@
     }
 
     AutoMutex lock(mLock);
-    if (isOffloadedOrDirect_l()) {
+    // FIXME: offloaded and direct tracks call into the HAL for render positions
+    // for compressed/synced data; however, we use proxy position for pure linear pcm data
+    // as we do not know the capability of the HAL for pcm position support and standby.
+    // There may be some latency differences between the HAL position and the proxy position.
+    if (isOffloadedOrDirect_l() && !isPurePcmData_l()) {
         uint32_t dspFrames = 0;
 
         if (isOffloaded_l() && ((mState == STATE_PAUSED) || (mState == STATE_PAUSED_STOPPING))) {