Fix ChunkDemuxer seek deadlock

media/filters/ffmpeg_video_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_video_decoder.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/message_loop.h"
 #include "base/string_number_conversions.h"
@@ skipping 11 matching lines @@
 
 // Always try to use three threads for video decoding.  There is little reason
 // not to since current day CPUs tend to be multi-core and we measured
 // performance benefits on older machines such as P4s with hyperthreading.
 //
 // Handling decoding on separate threads also frees up the pipeline thread to
 // continue processing. Although it'd be nice to have the option of a single
 // decoding thread, FFmpeg treats having one thread the same as having zero
 // threads (i.e., avcodec_decode_video() will execute on the calling thread).
 // Yet another reason for having two threads :)
-static const int kDecodeThreads = 2;
+static const int kDecodeThreads = 1;

[Ami GONE FROM CHROMIUM, 2012/01/27 23:44:58]

??

[acolwell GONE FROM CHROMIUM, 2012/01/29 03:00:41]

This was to temporarily make valgrind shutup about FFVP8. I've reverted this
change for now. Fixing valgrind issues is the next thing on my list
(http://crbug.com/109875).

 static const int kMaxDecodeThreads = 16;
 
 // Returns the number of threads given the FFmpeg CodecID. Also inspects the
 // command line for a valid --video-threads flag.
 static int GetThreadCount(CodecID codec_id) {
   // TODO(scherkus): As of 07/21/2011 we still can't enable Theora multithreaded
   // decoding due to bugs in FFmpeg. Dig in and send fixes upstream!
   //
   // Refer to http://crbug.com/93932 for tsan suppressions on decoding.
   int decode_threads = (codec_id == CODEC_ID_THEORA ? 1 : kDecodeThreads);
@@ skipping 171 matching lines @@
   message_loop_->PostTask(FROM_HERE, base::Bind(
       &FFmpegVideoDecoder::DoDecodeBuffer, this, buffer));
 }
 
 void FFmpegVideoDecoder::DoDecodeBuffer(const scoped_refptr<Buffer>& buffer) {
   DCHECK_EQ(MessageLoop::current(), message_loop_);
   DCHECK_NE(state_, kUninitialized);
   DCHECK_NE(state_, kDecodeFinished);
   DCHECK(!read_cb_.is_null());
 
+  if (!buffer) {

[Ami GONE FROM CHROMIUM, 2012/01/27 23:44:58]

GpuVideoDecoder::RequestBufferDecode needs to similarly change?

[acolwell GONE FROM CHROMIUM, 2012/01/29 03:00:41]

Done.

+    DeliverFrame(NULL);
+    return;
+  }
+
   // During decode, because reads are issued asynchronously, it is possible to
   // receive multiple end of stream buffers since each read is acked. When the
   // first end of stream buffer is read, FFmpeg may still have frames queued
   // up in the decoder so we need to go through the decode loop until it stops
   // giving sensible data.  After that, the decoder should output empty
   // frames.  There are three states the decoder can be in:
   //
   //   kNormal: This is the starting state. Buffers are decoded. Decode errors
   //            are discarded.
   //   kFlushCodec: There isn't any more input data. Call avcodec_decode_video2
@@ skipping 167 matching lines @@
 scoped_refptr<VideoFrame> FFmpegVideoDecoder::AllocateVideoFrame() {
   VideoFrame::Format format = PixelFormatToVideoFormat(codec_context_->pix_fmt);
   size_t width = codec_context_->width;
   size_t height = codec_context_->height;
 
   return VideoFrame::CreateFrame(format, width, height,
                                  kNoTimestamp(), kNoTimestamp());
 }
 
 }  // namespace media