Have FFmpeg Decoders handle 0 byte buffers instead of FFmpeg

media/filters/ffmpeg_audio_decoder.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_audio_decoder.h"
 
 #include <stdint.h>
 
 #include "base/callback_helpers.h"
 #include "base/single_thread_task_runner.h"
@@ skipping 168 matching lines @@
   DCHECK(!*has_produced_frame);
 
   AVPacket packet;
   av_init_packet(&packet);
   if (buffer->end_of_stream()) {
     packet.data = NULL;
     packet.size = 0;
   } else {
     packet.data = const_cast<uint8_t*>(buffer->data());
     packet.size = buffer->data_size();
+
+    // Since we're not at EOS and there is no data available in the current
+    // buffer, simply return and let the caller provide more data.
+    // crbug.com/663438 has more context on 0-byte buffers.
+    if (!packet.size)
+      return true;
   }
 
   // Each audio packet may contain several frames, so we must call the decoder
   // until we've exhausted the packet.  Regardless of the packet size we always
   // want to hand it to the decoder at least once, otherwise we would end up
   // skipping end of stream packets since they have a size of zero.
   do {
     int frame_decoded = 0;
     const int result = avcodec_decode_audio4(
         codec_context_.get(), av_frame_.get(), &frame_decoded, &packet);
@@ skipping 252 matching lines @@
   // Now create an AVBufferRef for the data just allocated. It will own the
   // reference to the AudioBuffer object.
   AudioBuffer* opaque = buffer.get();
   opaque->AddRef();
   frame->buf[0] = av_buffer_create(frame->data[0], buffer_size_in_bytes,
                                    ReleaseAudioBufferImpl, opaque, 0);
   return 0;
 }
 
 }  // namespace media