media: Add support for playback of VP8 Alpha video streams

media/filters/ffmpeg_demuxer.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "media/filters/ffmpeg_demuxer.h"
 
 #include <algorithm>
 #include <string>
 
 #include "base/base64.h"
@@ skipping 77 matching lines @@
     DCHECK(!enc_key_id.empty());
     if (enc_key_id.empty())
       return;
 
     encryption_key_id_.assign(enc_key_id);
     demuxer_->FireNeedKey(kWebMEncryptInitDataType, enc_key_id);
   }
 }
 
 void FFmpegDemuxerStream::EnqueuePacket(ScopedAVPacket packet) {
+
   DCHECK(message_loop_->BelongsToCurrentThread());
 
   if (stopped_ || end_of_stream_) {
     NOTREACHED() << "Attempted to enqueue packet on a stopped stream";
     return;
   }
 
   // Convert the packet if there is a bitstream filter.
   if (packet->data && bitstream_converter_enabled_ &&
       !bitstream_converter_->ConvertPacket(packet.get())) {
     LOG(ERROR) << "Format conversion failed.";
   }
 
+  // Get side data if any. For now, the only type of side_data is VP8 Alpha. We
+  // keep this generic so that other side_data types in the future can be
+  // handled the same way as well.
+  uint8* side_data;

[scherkus (not reviewing), 2013/04/04 22:54:00]

nit: I'd declare + assign on same line

[vignesh, 2013/04/05 19:06:58]

Done.

+  int side_data_size = 0;
+  av_packet_split_side_data(packet.get());
+  side_data = av_packet_get_side_data(packet.get(),
+                                      AV_PKT_DATA_MATROSKA_BLOCKADDITIONAL,
+                                      &side_data_size);
+
   // If a packet is returned by FFmpeg's av_parser_parse2() the packet will
   // reference inner memory of FFmpeg.  As such we should transfer the packet
   // into memory we control.
   scoped_refptr<DecoderBuffer> buffer;
-  buffer = DecoderBuffer::CopyFrom(packet->data, packet->size);
+  if (side_data_size > 0) {
+    buffer = DecoderBuffer::CopyFrom(packet.get()->data, packet.get()->size,
+                                     side_data, side_data_size);
+  } else {
+    buffer = DecoderBuffer::CopyFrom(packet.get()->data, packet.get()->size);
+  }
 
   if ((type() == DemuxerStream::AUDIO && audio_config_.is_encrypted()) ||
       (type() == DemuxerStream::VIDEO && video_config_.is_encrypted())) {
     scoped_ptr<DecryptConfig> config(WebMCreateDecryptConfig(
         packet->data,  packet->size,
         reinterpret_cast<const uint8*>(encryption_key_id_.data()),
         encryption_key_id_.size()));
     if (!config)
       LOG(ERROR) << "Creation of DecryptConfig failed.";
     buffer->SetDecryptConfig(config.Pass());
@@ skipping 604 matching lines @@
   }
   for (size_t i = 0; i < buffered.size(); ++i)
     host_->AddBufferedTimeRange(buffered.start(i), buffered.end(i));
 }
 
 void FFmpegDemuxer::OnDataSourceError() {
   host_->OnDemuxerError(PIPELINE_ERROR_READ);
 }
 
 }  // namespace media