Set AVFMT_FLAG_GENPTS when demuxing AVI content.

Storing MPEG-4 B-frames in AVI has always been a bit of a hack and by default av_read_frame() will return non-timestamped video packets for such content. AVFMT_FLAG_GENPTS takes advantage of AVI's constant framerate to generate presentation timestamps at the expense of parsing delay.

BUG=169570

Review URL: https://codereview.chromium.org/12209111

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@182310 0039d316-1c4b-4281-b951-d872f2087c98

content/browser/media/media_browsertest.cc

@@ -123,10 +123,7 @@ IN_PROC_BROWSER_TEST_P(MediaTest, VideoBearAviMp3Mpeg4) {
   PlayVideo("bear_mpeg4_mp3.avi", GetParam());
 }
 
-// TODO(scherkus): MPEG-4 ASP contains B-frames and out-of-order decoding, which
-// makes FFmpeg spit out video frames with no timestamp. As a result we DCHECK()
-// all over the place http://crbug.com/169570
-IN_PROC_BROWSER_TEST_P(MediaTest, DISABLED_VideoBearAviMp3Mpeg4Asp) {
+IN_PROC_BROWSER_TEST_P(MediaTest, VideoBearAviMp3Mpeg4Asp) {
   PlayVideo("bear_mpeg4asp_mp3.avi", GetParam());
 }
 

media/filters/ffmpeg_demuxer.cc

@@ -478,6 +478,11 @@ void FFmpegDemuxer::OnFindStreamInfoDone(const PipelineStatusCB& status_cb,
   if (start_time_ == kNoTimestamp())
     start_time_ = base::TimeDelta();
 
+  // MPEG-4 B-frames cause grief for a simple container like AVI. Enable PTS
+  // generation so we always get timestamps, see http://crbug.com/169570
+  if (strcmp(format_context->iformat->name, "avi") == 0)
+    format_context->flags |= AVFMT_FLAG_GENPTS;
+
   // Good to go: set the duration and bitrate and notify we're done
   // initializing.
   host_->SetDuration(max_duration);