Create video and audio decoder threads on demand.

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 33 matching lines @@
   const CommandLine* cmd_line = CommandLine::ForCurrentProcess();
   std::string threads(cmd_line->GetSwitchValueASCII(switches::kVideoThreads));
   if (threads.empty() || !base::StringToInt(threads, &decode_threads))
     return decode_threads;
 
   decode_threads = std::max(decode_threads, 0);
   decode_threads = std::min(decode_threads, kMaxDecodeThreads);
   return decode_threads;
 }
 
-FFmpegVideoDecoder::FFmpegVideoDecoder(MessageLoop* message_loop)
-    : message_loop_(message_loop),
+FFmpegVideoDecoder::FFmpegVideoDecoder(
+    const base::Callback<MessageLoop*()>& message_loop_cb)
+    : message_loop_factory_cb_(message_loop_cb),
+      message_loop_(NULL),
       state_(kUninitialized),
       codec_context_(NULL),
       av_frame_(NULL),
       frame_rate_numerator_(0),
       frame_rate_denominator_(0) {
 }
 
 FFmpegVideoDecoder::~FFmpegVideoDecoder() {
   ReleaseFFmpegResources();
 }
 
 void FFmpegVideoDecoder::Initialize(DemuxerStream* demuxer_stream,
                                     const PipelineStatusCB& pipeline_status_cb,
                                     const StatisticsCB& statistics_cb) {
+  if (!message_loop_) {
+    message_loop_ = message_loop_factory_cb_.Run();
+    message_loop_factory_cb_.Reset();
+  } else {
+    // TODO(scherkus): initialization currently happens more than once in
+    // PipelineIntegrationTest.BasicPlayback.
+    LOG(ERROR) << "Initialize has already been called.";
+  }
+
   if (MessageLoop::current() != message_loop_) {
     message_loop_->PostTask(FROM_HERE, base::Bind(
         &FFmpegVideoDecoder::Initialize, this,
         make_scoped_refptr(demuxer_stream), pipeline_status_cb, statistics_cb));
     return;
   }
 
   DCHECK(!demuxer_stream_);
 
   if (!demuxer_stream) {
@@ skipping 337 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