From 1024b041e824bb6eb232971fc4a2984d63f7e079 Mon Sep 17 00:00:00 2001
From: Jeff Tinker <jtinker@google.com>
Date: Thu, 31 May 2012 21:41:40 -0700
Subject: [PATCH] Part of fix for double spins & faster startup

This change alters the way that the media player
interacts with the Widevine adaptive streaming buffer
logic.  It eliminates the reliance on cached buffer
duration to determine pause/play states and instead
only generates buffering events when the widevine
library is not producing data (i.e. when it is
buffering).  This eliminates unnecessary pause and
rebuffer cycles, reducing startup time and the
frequency and duration of spinners.

Multi-repo commit, depends on related changes in frameworks/av

Change-Id: I5b71f954268fbd390eed7f27db98a1bb470d5cfb
related-to-bug:6503294
related-to-bug:6463780
---
 proprietary/wvm/WVMExtractorImpl.cpp     | 21 ++++++++++-----------
 proprietary/wvm/WVMMediaSource.cpp       |  9 +++++++++
 proprietary/wvm/include/WVMMediaSource.h |  2 ++
 3 files changed, 21 insertions(+), 11 deletions(-)

diff --git a/proprietary/wvm/WVMExtractorImpl.cpp b/proprietary/wvm/WVMExtractorImpl.cpp
index b1f4a2f0..fe941f59 100644
--- a/proprietary/wvm/WVMExtractorImpl.cpp
+++ b/proprietary/wvm/WVMExtractorImpl.cpp
@@ -499,19 +499,24 @@ int64_t WVMExtractorImpl::getCachedDurationUs(status_t *finalStatus) {
     }
 
     uint64_t durationUs = 0;
-    float secondsBuffered;
-    status = WV_Info_TimeBuffered(mSession, &secondsBuffered);
+
+    if (!mVideoSource->isStalled() && !mAudioSource->isStalled()) {
+        // Data is buffered as long as the pull isn't stalled.
+        // The amount indicated doesn't matter as long as it
+        // is more than the high water mark.
+        durationUs = 10000000LL;
+    }
+
     if (status == WV_Status_End_Of_Media) {
         *finalStatus = ERROR_END_OF_STREAM;
     } else if (status != WV_Status_OK) {
         *finalStatus = ERROR_IO;
     } else {
-        durationUs = (uint64_t)(secondsBuffered * 1000000LL);
-
         if (mIsLiveStream) {
             *finalStatus = ERROR_END_OF_STREAM;
         } else {
             *finalStatus = OK;
+
             int64_t current_time = 0;  // usec.
             if (mVideoSource != NULL) {
                 current_time = mVideoSource->getTime();
@@ -530,13 +535,7 @@ int64_t WVMExtractorImpl::getCachedDurationUs(status_t *finalStatus) {
         }
     }
 
-    // Scale the duration to account for Stagefright's conservative buffering.
-    // This provides much more responsive operation and due to the ability to
-    // adapt, we don't need to prebuffer so much data.  Based on testing, 2x
-    // is a reasonable compromise between faster startup time and additional
-    // pauses after playback starts.
-
-    return durationUs * 2;
+    return durationUs;
 }
 
 void WVMExtractorImpl::setAdaptiveStreamingMode(bool adaptive)
diff --git a/proprietary/wvm/WVMMediaSource.cpp b/proprietary/wvm/WVMMediaSource.cpp
index 60eaaa28..7d86fe66 100644
--- a/proprietary/wvm/WVMMediaSource.cpp
+++ b/proprietary/wvm/WVMMediaSource.cpp
@@ -35,6 +35,7 @@ WVMMediaSource::WVMMediaSource(WVSession *session, WVEsSelector esSelector,
       mIsLiveStream(isLive),
       mNewSegment(false),
       mCryptoInitialized(false),
+      mIsStalled(false),
       mGroup(NULL),
       mKeyTime(0),
       mDts(0),
@@ -203,6 +204,8 @@ status_t WVMMediaSource::read(MediaBuffer **buffer, const ReadOptions *options)
 {
     Mutex::Autolock autoLock(mLock);
 
+    mIsStalled = false;
+
     CHECK(mStarted);
 
     *buffer = NULL;
@@ -333,16 +336,20 @@ status_t WVMMediaSource::read(MediaBuffer **buffer, const ReadOptions *options)
                 return ERROR_IO;
             } else {
                 // Didn't get anything, sleep a bit so we don't hog the CPU then try again
+                if (retryCount > 10)
+                    mIsStalled = true;
                 usleep(10000);
                 continue;
             }
         }
 
+
 #define PCR_HZ 90000
         mKeyTime = (int64_t)mPts * 1000000 / PCR_HZ;
 
         if (seekNextSync && ((mKeyTime < seekTimeUs) || !syncFrame)) {
             // drop frames up to next sync if requested
+            mIsStalled = true;
             usleep(10000);
 #ifdef REQUIRE_SECURE_BUFFERS
             mDecryptContext.Initialize(mediaBuf);
@@ -351,6 +358,8 @@ status_t WVMMediaSource::read(MediaBuffer **buffer, const ReadOptions *options)
             continue;
         }
 
+        mIsStalled = false;
+
         if (offset + bytesRead < mediaBuf->size())
             break;
 
diff --git a/proprietary/wvm/include/WVMMediaSource.h b/proprietary/wvm/include/WVMMediaSource.h
index 57d4b287..b16ce57a 100644
--- a/proprietary/wvm/include/WVMMediaSource.h
+++ b/proprietary/wvm/include/WVMMediaSource.h
@@ -41,6 +41,7 @@ public:
     virtual status_t read(MediaBuffer **buffer, const ReadOptions *options = NULL);
 
     void addEncryptedSize(size_t size) { mEncryptedSizes.push_back(size); }
+    bool isStalled() const { return mIsStalled; }
 
     static int sLastError;
 
@@ -83,6 +84,7 @@ private:
     bool mIsLiveStream;
     bool mNewSegment;
     bool mCryptoInitialized;
+    bool mIsStalled;
 
     MediaBufferGroup *mGroup;