From 1b78c4b1484c7d4c12b9a87329dc8d4b6e8c0c37 Mon Sep 17 00:00:00 2001
From: Lajos Molnar <lajos@google.com>
Date: Wed, 30 Apr 2014 11:10:44 -0700
Subject: Smooth out AwesomePlayer

Use clock estimator to smooth out audio time stamps.

Change-Id: Iec1ff30c011069d06ff8051fc4839d00895463d6
---
 media/libstagefright/AwesomePlayer.cpp       | 26 ++++++++++++++++++++++----
 media/libstagefright/include/AwesomePlayer.h |  3 +++
 2 files changed, 25 insertions(+), 4 deletions(-)

(limited to 'media')

diff --git a/media/libstagefright/AwesomePlayer.cpp b/media/libstagefright/AwesomePlayer.cpp
index 391392e..e66ccd9 100644
--- a/media/libstagefright/AwesomePlayer.cpp
+++ b/media/libstagefright/AwesomePlayer.cpp
@@ -40,6 +40,7 @@
 #include <media/stagefright/foundation/ADebug.h>
 #include <media/stagefright/timedtext/TimedTextDriver.h>
 #include <media/stagefright/AudioPlayer.h>
+#include <media/stagefright/ClockEstimator.h>
 #include <media/stagefright/DataSource.h>
 #include <media/stagefright/FileSource.h>
 #include <media/stagefright/MediaBuffer.h>
@@ -228,6 +229,8 @@ AwesomePlayer::AwesomePlayer()
                               &AwesomePlayer::onAudioTearDownEvent);
     mAudioTearDownEventPending = false;
 
+    mClockEstimator = new WindowedLinearFitEstimator();
+
     reset();
 }
 
@@ -1859,21 +1862,27 @@ void AwesomePlayer::onVideoEvent() {
     TimeSource *ts =
         ((mFlags & AUDIO_AT_EOS) || !(mFlags & AUDIOPLAYER_STARTED))
             ? &mSystemTimeSource : mTimeSource;
+    int64_t systemTimeUs = mSystemTimeSource.getRealTimeUs();
 
     if (mFlags & FIRST_FRAME) {
         modifyFlags(FIRST_FRAME, CLEAR);
         mSinceLastDropped = 0;
-        mTimeSourceDeltaUs = ts->getRealTimeUs() - timeUs;
+        mClockEstimator->reset();
+        mTimeSourceDeltaUs = estimateRealTimeUs(ts, systemTimeUs) - timeUs;
     }
 
     int64_t realTimeUs, mediaTimeUs;
     if (!(mFlags & AUDIO_AT_EOS) && mAudioPlayer != NULL
         && mAudioPlayer->getMediaTimeMapping(&realTimeUs, &mediaTimeUs)) {
+        ALOGV("updating TSdelta (%" PRId64 " => %" PRId64 " change %" PRId64 ")",
+              mTimeSourceDeltaUs, realTimeUs - mediaTimeUs,
+              mTimeSourceDeltaUs - (realTimeUs - mediaTimeUs));
+        ATRACE_INT("TS delta change (ms)", (mTimeSourceDeltaUs - (realTimeUs - mediaTimeUs)) / 1E3);
         mTimeSourceDeltaUs = realTimeUs - mediaTimeUs;
     }
 
     if (wasSeeking == SEEK_VIDEO_ONLY) {
-        int64_t nowUs = ts->getRealTimeUs() - mTimeSourceDeltaUs;
+        int64_t nowUs = estimateRealTimeUs(ts, systemTimeUs) - mTimeSourceDeltaUs;
 
         int64_t latenessUs = nowUs - timeUs;
 
@@ -1887,7 +1896,7 @@ void AwesomePlayer::onVideoEvent() {
     if (wasSeeking == NO_SEEK) {
         // Let's display the first frame after seeking right away.
 
-        int64_t nowUs = ts->getRealTimeUs() - mTimeSourceDeltaUs;
+        int64_t nowUs = estimateRealTimeUs(ts, systemTimeUs) - mTimeSourceDeltaUs;
 
         int64_t latenessUs = nowUs - timeUs;
 
@@ -2009,7 +2018,8 @@ void AwesomePlayer::onVideoEvent() {
 
         int64_t nextTimeUs;
         CHECK(mVideoBuffer->meta_data()->findInt64(kKeyTime, &nextTimeUs));
-        int64_t delayUs = nextTimeUs - ts->getRealTimeUs() + mTimeSourceDeltaUs;
+        systemTimeUs = mSystemTimeSource.getRealTimeUs();
+        int64_t delayUs = nextTimeUs - estimateRealTimeUs(ts, systemTimeUs) + mTimeSourceDeltaUs;
         ATRACE_INT("Frame delta (ms)", (nextTimeUs - timeUs) / 1E3);
         ALOGV("next frame in %" PRId64, delayUs);
         // try to schedule at least 12ms before due time, or just on time
@@ -2020,6 +2030,14 @@ void AwesomePlayer::onVideoEvent() {
     postVideoEvent_l();
 }
 
+int64_t AwesomePlayer::estimateRealTimeUs(TimeSource *ts, int64_t systemTimeUs) {
+    if (ts == &mSystemTimeSource) {
+        return systemTimeUs;
+    } else {
+        return (int64_t)mClockEstimator->estimate(systemTimeUs, ts->getRealTimeUs());
+    }
+}
+
 void AwesomePlayer::postVideoEvent_l(int64_t delayUs) {
     ATRACE_CALL();
 
diff --git a/media/libstagefright/include/AwesomePlayer.h b/media/libstagefright/include/AwesomePlayer.h
index 271df8e..6ee95a9 100644
--- a/media/libstagefright/include/AwesomePlayer.h
+++ b/media/libstagefright/include/AwesomePlayer.h
@@ -32,6 +32,7 @@
 namespace android {
 
 struct AudioPlayer;
+struct ClockEstimator;
 struct DataSource;
 struct MediaBuffer;
 struct MediaExtractor;
@@ -234,6 +235,7 @@ private:
 
     MediaBuffer *mVideoBuffer;
 
+    sp<ClockEstimator> mClockEstimator;
     sp<HTTPBase> mConnectingDataSource;
     sp<NuCachedSource2> mCachedSource;
 
@@ -293,6 +295,7 @@ private:
 
     bool getBitrate(int64_t *bitrate);
 
+    int64_t estimateRealTimeUs(TimeSource *ts, int64_t systemTimeUs);
     void finishSeekIfNecessary(int64_t videoTimeUs);
     void ensureCacheIsFetching_l();
 
-- 
cgit v1.1