Quick work around for av_seek_frame() causing video to go completely out of sync.

If we have a freshly opened AVFormatContext, telling it to seek to the beginning (pts=0) apparently causes the video and/or audio streams to get timestampped incorrectly, causing video sync issues.  If the video has been playing a bit, a seek to the beginning causes no issues.  Go figure.

BUG=17832
TEST=ogg videos should remain in sync

Review URL: http://codereview.chromium.org/159438

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@21720 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 29 insertions, 1 deletions

diff --git a/media/filters/ffmpeg_demuxer.cc b/media/filters/ffmpeg_demuxer.cc
index c3b2d62..189aac4 100644
--- a/media/filters/ffmpeg_demuxer.cc
+++ b/media/filters/ffmpeg_demuxer.cc
@@ -220,7 +220,8 @@ FFmpegDemuxer::FFmpegDemuxer()
       read_event_(false, false),
       read_has_failed_(false),
       last_read_bytes_(0),
-      read_position_(0) {
+      read_position_(0),
+      first_seek_hack_(true) {
 }
 
 FFmpegDemuxer::~FFmpegDemuxer() {
@@ -425,6 +426,16 @@ void FFmpegDemuxer::SeekTask(base::TimeDelta time, FilterCallback* callback) {
     (*iter)->FlushBuffers();
   }
 
+  // Do NOT call av_seek_frame() if we were just created.  For some reason it
+  // causes Ogg+Theora/Vorbis videos to become heavily out of sync.
+  //
+  // TODO(scherkus): fix the av_seek_frame() hackery!
+  if (first_seek_hack_) {
+    first_seek_hack_ = false;
+    callback->Run();
+    return;
+  }
+
   // Seek backwards if requested timestamp is behind FFmpeg's current time.
   int flags = 0;
   if (time <= current_timestamp_) {
diff --git a/media/filters/ffmpeg_demuxer.h b/media/filters/ffmpeg_demuxer.h
index ebd1274..0777855 100644
--- a/media/filters/ffmpeg_demuxer.h
+++ b/media/filters/ffmpeg_demuxer.h
@@ -219,6 +219,10 @@ class FFmpegDemuxer : public Demuxer,
   size_t last_read_bytes_;
   int64 read_position_;
 
+  // If true, then it's our first seek and we won't call av_read_frame().  It's
+  // a hack to get around some issue with FFmpeg.
+  bool first_seek_hack_;
+
   DISALLOW_COPY_AND_ASSIGN(FFmpegDemuxer);
 };
 
diff --git a/media/filters/ffmpeg_demuxer_unittest.cc b/media/filters/ffmpeg_demuxer_unittest.cc
index 08580da..e8c9df7 100644
--- a/media/filters/ffmpeg_demuxer_unittest.cc
+++ b/media/filters/ffmpeg_demuxer_unittest.cc
@@ -456,6 +456,13 @@ TEST_F(FFmpegDemuxerTest, Seek) {
   EXPECT_CALL(*MockFFmpeg::get(), AVFreePacket(_)).WillOnce(FreePacket());
   EXPECT_CALL(*MockFFmpeg::get(), AVFreePacket(_)).WillOnce(FreePacket());
 
+  // ... then we'll call Seek() to get around the first seek hack...
+  //
+  // TODO(scherkus): fix the av_seek_frame() hackery!
+  StrictMock<MockFilterCallback> hack_callback;
+  EXPECT_CALL(hack_callback, OnFilterCallback());
+  EXPECT_CALL(hack_callback, OnCallbackDestroyed());
+
   // ...then we'll expect the actual seek call...
   EXPECT_CALL(*MockFFmpeg::get(),
       AVSeekFrame(&format_context_, -1, kExpectedTimestamp, kExpectedFlags))
@@ -501,6 +508,12 @@ TEST_F(FFmpegDemuxerTest, Seek) {
   message_loop_.RunAllPending();
   MockFFmpeg::get()->CheckPoint(1);
 
+  // Issue a preliminary seek to get around the "first seek" hack.
+  //
+  // TODO(scherkus): fix the av_seek_frame() hackery!
+  demuxer_->Seek(base::TimeDelta(), hack_callback.NewCallback());
+  message_loop_.RunAllPending();
+
   // Now issue a simple forward seek, which should discard queued packets.
   demuxer_->Seek(base::TimeDelta::FromMicroseconds(kExpectedTimestamp),
                  seek_callback.NewCallback());