MJPEG acceleration for video capture using VAAPI

content/common/gpu/client/gpu_channel_host.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 "content/common/gpu/client/gpu_channel_host.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/message_loop/message_loop.h"
 #include "base/message_loop/message_loop_proxy.h"
 #include "base/posix/eintr_wrapper.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/trace_event/trace_event.h"
 #include "content/common/gpu/client/command_buffer_proxy_impl.h"
+#include "content/common/gpu/client/gpu_jpeg_decode_accelerator_host.h"
 #include "content/common/gpu/gpu_messages.h"
 #include "ipc/ipc_sync_message_filter.h"
 #include "url/gurl.h"
 
 #if defined(OS_WIN)
 #include "content/public/common/sandbox_init.h"
 #endif
 
 using base::AutoLock;
 using base::MessageLoopProxy;
@@ skipping 223 matching lines @@
 
 scoped_ptr<media::VideoEncodeAccelerator> GpuChannelHost::CreateVideoEncoder(
     int command_buffer_route_id) {
   TRACE_EVENT0("gpu", "GpuChannelHost::CreateVideoEncoder");
   AutoLock lock(context_lock_);
   ProxyMap::iterator it = proxies_.find(command_buffer_route_id);
   DCHECK(it != proxies_.end());
   return it->second->CreateVideoEncoder();
 }
 
+scoped_ptr<media::JpegDecodeAccelerator> GpuChannelHost::CreateJpegDecoder(
+    scoped_refptr<base::MessageLoopProxy> reply_loop) {
+  TRACE_EVENT0("gpu", "GpuChannelHost::CreateJpegDecoder");
+  // This function is called from GpuJpegDecoder's main task thread, which is

[wuchengli, 2015/04/24 05:54:23]

Just call it task thread. main task thread sounds confusing.

[kcwu, 2015/04/30 19:25:40]

Done.

+  // not main thread.
+
+  int32 route_id = GenerateRouteID();
+  GpuJpegDecodeAcceleratorHost* decoder(
+      new GpuJpegDecodeAcceleratorHost(this, route_id,
+                                       factory_->GetIOLoopProxy()));
+
+  // GpuJpegDecoder's main task thread (i.e., device thread on Linux) is
+  // usually blocking wait for next frame, so it expects decoder responses are

[wuchengli, 2015/04/24 05:54:23]

s/blocking wait/waiting/.

Here it refers to the main task thread, which doesn't expect anything. I think
this is clearer. s/it expects decoder responses are send/decoder responses are
sent/. 

[kcwu, 2015/04/30 19:25:40]

Done.

+  // send to |reply_loop| directly.
+  scoped_refptr<base::MessageLoopProxy> io_loop = factory_->GetIOLoopProxy();
+  io_loop->PostTask(FROM_HERE,
+                    base::Bind(&GpuChannelHost::MessageFilter::AddRoute,
+                               channel_filter_.get(), route_id,
+                               decoder->AsWeakPtr(), reply_loop));

[wuchengli, 2015/04/24 05:54:23]

Why not just use |io_loop|? reply_loop is always IO thread.
GpuJpegDecoder::Initialize also hard-codes the IO thread there. DCHECK in
VideoFrameReady should make sure it's the right thread.

[kcwu, 2015/04/30 19:25:40]

I want to make these thread logic stay in GpuJpegDecoder as much as possible.
Make GpuChannelHost neutral.

+  return scoped_ptr<media::JpegDecodeAccelerator>(decoder);
+}
+
 void GpuChannelHost::DestroyCommandBuffer(
     CommandBufferProxyImpl* command_buffer) {
   TRACE_EVENT0("gpu", "GpuChannelHost::DestroyCommandBuffer");
 
   int route_id = command_buffer->GetRouteID();
   Send(new GpuChannelMsg_DestroyCommandBuffer(route_id));
   RemoveRoute(route_id);
 
   AutoLock lock(context_lock_);
   proxies_.erase(route_id);
@@ skipping 157 matching lines @@
 
   listeners_.clear();
 }
 
 bool GpuChannelHost::MessageFilter::IsLost() const {
   AutoLock lock(lock_);
   return lost_;
 }
 
 }  // namespace content