Prevent current time jumping around when seek

BUG=19396
TEST=Open a .ogg file, seek, now the thumb won't jumps to 0 back and forth again.

Using a <video> to play a video file, when you seek
(especially ogg files) it will jump to time = 0 and
jumps back to the desired seek position back and forth.
This is because ogg files are muxed in a way that
audio packets have large gaps between valid timestamps.
This patch will avoid using invalid timestamps from
audio packets to estimate the current time.

Review URL: http://codereview.chromium.org/173027

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@23754 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 10 insertions, 3 deletions

diff --git a/media/filters/ffmpeg_audio_decoder.cc b/media/filters/ffmpeg_audio_decoder.cc
index 6f4f5e1..e103093 100644
--- a/media/filters/ffmpeg_audio_decoder.cc
+++ b/media/filters/ffmpeg_audio_decoder.cc
@@ -128,9 +128,16 @@ void FFmpegAudioDecoder::OnDecode(Buffer* input) {
       result_buffer->SetTimestamp(input->GetTimestamp());
     }
 
-    // Update our estimated timestamp for the next packet.
-    estimated_next_timestamp_ = result_buffer->GetTimestamp() +
-        result_buffer->GetDuration();
+    // Only use the timestamp of |result_buffer| to estimate the next timestamp
+    // if it is valid (i.e. greater than 0).  Otherwise the error will stack
+    // together and we will get a series of incorrect timestamps.  In this case,
+    // this will maintain a series of zero timestamps.
+    // TODO(hclam): We should use another invalid value other than 0.
+    if (result_buffer->GetTimestamp().InMicroseconds() > 0) {
+      // Update our estimated timestamp for the next packet.
+      estimated_next_timestamp_ = result_buffer->GetTimestamp() +
+          result_buffer->GetDuration();
+    }
 
     EnqueueResult(result_buffer);
     return;