MJPEG acceleration for video capture using VAAPI

content/common/gpu/media/gpu_jpeg_decode_accelerator.h

+// Copyright 2015 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.
+
+#ifndef CONTENT_COMMON_GPU_MEDIA_GPU_JPEG_DECODE_ACCELERATOR_H_
+#define CONTENT_COMMON_GPU_MEDIA_GPU_JPEG_DECODE_ACCELERATOR_H_
+
+#include "base/compiler_specific.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/shared_memory.h"
+#include "base/synchronization/waitable_event.h"
+#include "ipc/ipc_listener.h"
+#include "ipc/ipc_sender.h"
+#include "media/video/jpeg_decode_accelerator.h"
+
+struct AcceleratedJpegDecoderMsg_Decode_Params;
+
+namespace base {
+class MessageLoopProxy;
+}
+
+namespace content {
+class GpuChannel;
+
+class GpuJpegDecodeAccelerator : public IPC::Listener,
+                                 public IPC::Sender,
+                                 public media::JpegDecodeAccelerator::Client {
+ public:
+  // Each of the arguments to the constructor must outlive this object.

[wuchengli, 2015/04/15 07:11:58]

Just say "|channel| must outlive this object". |host_route_id| doesn't apply.

[kcwu, 2015/04/16 14:38:28]

Done.

+  GpuJpegDecodeAccelerator(
+      GpuChannel* channel,
+      int32 host_route_id,
+      const scoped_refptr<base::MessageLoopProxy>& io_message_loop);
+
+  void Destroy();
+
+  // IPC::Listener implementation.
+  bool OnMessageReceived(const IPC::Message& message) override;
+
+  // media::JpegDecodeAccelerator::Client implementation.
+  void VideoFrameReady(int32_t bitstream_buffer_id) override;
+  void NotifyError(int32_t bitstream_buffer_id,
+                   media::JpegDecodeAccelerator::Error error) override;
+
+  // Function to delegate sending to actual sender.
+  bool Send(IPC::Message* message) override;
+
+  bool Initialize();
+
+ private:
+  ~GpuJpegDecodeAccelerator();
+  class MessageFilter;
+
+  // Handlers for IPC messages.
+  void OnDecode(const AcceleratedJpegDecoderMsg_Decode_Params& params);
+  void OnDestroy();
+
+  // Called on IO thread when |filter_| has been removed.
+  void OnFilterRemoved();
+
+  // The lifetime of objects of this class is managed by a GpuChannel. The
+  // GpuChannels destroy all the GpuCommandBufferStubs that they own when they

[wuchengli, 2015/04/15 07:11:58]

update the comment

[kcwu, 2015/04/20 17:47:59]

Done.

+  // are destroyed. So a raw pointer is safe.
+  GpuChannel* channel_;
+
+  // Route ID to communicate with the host.
+  int32 host_route_id_;
+
+  // The underlying JpegDecodeAccelerator.
+  scoped_ptr<media::JpegDecodeAccelerator> jpeg_decode_accelerator_;
+
+  // The message filter to run JDA::Decode on IO thread.
+  scoped_refptr<MessageFilter> filter_;
+
+  // Used to wait on for |filter_| to be removed, before we can safely
+  // destroy the JDA.
+  base::WaitableEvent filter_removed_;
+
+  // GPU child message loop.
+  scoped_refptr<base::MessageLoopProxy> child_message_loop_;
+
+  // GPU IO message loop.
+  scoped_refptr<base::MessageLoopProxy> io_message_loop_;
+
+  DISALLOW_IMPLICIT_CONSTRUCTORS(GpuJpegDecodeAccelerator);
+};
+
+}  // namespace content
+
+namespace base {
+
+template <class T>
+struct DefaultDeleter;
+
+// Specialize DefaultDeleter so that scoped_ptr<GpuJpegDecodeAccelerator> always
+// uses "Destroy()" instead of trying to use the destructor.
+template <>
+struct MEDIA_EXPORT DefaultDeleter<content::GpuJpegDecodeAccelerator> {
+ public:
+  void operator()(void* jpeg_decode_accelerator) const;
+};
+
+}  // namespace base
+
+#endif  // CONTENT_COMMON_GPU_MEDIA_GPU_JPEG_DECODE_ACCELERATOR_H_