Ensure media's buffered ranges always have a range that includes currentTime.

media/filters/ffmpeg_demuxer.cc

Index: media/filters/ffmpeg_demuxer.cc
diff --git a/media/filters/ffmpeg_demuxer.cc b/media/filters/ffmpeg_demuxer.cc
index 16c5447ae65ffa122e9c4887d36dd6f5290545d2..ece726aef5c7d897dae8067124043568b6a83169 100644
--- a/media/filters/ffmpeg_demuxer.cc
+++ b/media/filters/ffmpeg_demuxer.cc
@@ -30,13 +30,17 @@ namespace media {
 //
 // FFmpegDemuxerStream
 //
-FFmpegDemuxerStream::FFmpegDemuxerStream(FFmpegDemuxer* demuxer,
-                                         AVStream* stream)
-    : demuxer_(demuxer),
+FFmpegDemuxerStream::FFmpegDemuxerStream(
+    const NotifyBufferedCB& notify_buffered_cb,
+    FFmpegDemuxer* demuxer,
+    AVStream* stream)
+    : notify_buffered_cb_(notify_buffered_cb),
+      demuxer_(demuxer),
       stream_(stream),
       type_(UNKNOWN),
       discontinuous_(false),
-      stopped_(false) {
+      stopped_(false),
+      last_packet_timestamp_(kNoTimestamp()) {
   DCHECK(demuxer_);
 
   // Determine our media format.
@@ -94,6 +98,11 @@ void FFmpegDemuxerStream::EnqueuePacket(
         stream_->time_base, packet->pts));
     buffer->SetDuration(ConvertStreamTimestamp(
         stream_->time_base, packet->duration));
+    if (last_packet_timestamp_ != kNoTimestamp() &&
+        last_packet_timestamp_ < buffer->GetTimestamp()) {
+      notify_buffered_cb_.Run(last_packet_timestamp_, buffer->GetTimestamp());
+    }
+    last_packet_timestamp_ = buffer->GetTimestamp();
   }
 
   buffer_queue_.push_back(buffer);
@@ -106,6 +115,7 @@ void FFmpegDemuxerStream::FlushBuffers() {
   base::AutoLock auto_lock(lock_);
   DCHECK(read_queue_.empty()) << "Read requests should be empty";
   buffer_queue_.clear();
+  last_packet_timestamp_ = kNoTimestamp();
 }
 
 void FFmpegDemuxerStream::Stop() {
@@ -479,6 +489,7 @@ void FFmpegDemuxer::InitializeTask(DemuxerHost* host,
 
   // Create demuxer stream entries for each possible AVStream.
   streams_.resize(format_context_->nb_streams);
+  buffered_times_.resize(streams_.size());
   bool found_audio_stream = false;
   bool found_video_stream = false;
 
@@ -507,7 +518,9 @@ void FFmpegDemuxer::InitializeTask(DemuxerHost* host,
 
     AVStream* stream = format_context_->streams[i];
     scoped_refptr<FFmpegDemuxerStream> demuxer_stream(
-        new FFmpegDemuxerStream(this, stream));
+        new FFmpegDemuxerStream(
+            base::Bind(&FFmpegDemuxer::NotifyBufferedRange, this, i),
+            this, stream));
 
     streams_[i] = demuxer_stream;
     max_duration = std::max(max_duration, demuxer_stream->duration());
@@ -707,4 +720,15 @@ void FFmpegDemuxer::SignalReadCompleted(int size) {
   read_event_.Signal();
 }
 
+void FFmpegDemuxer::NotifyBufferedRange(
+    int stream_id, base::TimeDelta start, base::TimeDelta end) {
+  buffered_times_[stream_id].Add(start, end);

[scherkus (not reviewing), 2012/06/22 06:13:51]

I think each FDS stream should hold onto its own range + provide a public
accessor. Then this CB would be a simple notification and instead of iterating
over streams_ or buffered_times_ would do the intersection of non-NULL calls to
GetStream(AUDIO) and GetStream(VIDEO) (or roll your own for loop that plucks out
the appropriate FDS objects)

There's a bug here with multitrack files as unused streams will always have
buffered_times_ entries that are always empty/zero (i.e., the 0th track might be
a subtitles track!)

[Ami GONE FROM CHROMIUM, 2012/06/22 17:15:32]

Done.

+
+  Ranges<base::TimeDelta> buffered = buffered_times_[0];
+  for (size_t i = 1; i < streams_.size(); ++i)
+    buffered = buffered.IntersectionWith(buffered_times_[i]);
+  for (size_t i = 0; i < buffered.size(); ++i)
+    host_->AddBufferedTimeRange(buffered.start(i), buffered.end(i));
+}
+
 }  // namespace media