MJPEG acceleration for video capture using VAAPI

content/common/gpu/client/gpu_jpeg_decode_accelerator_host.cc

+// 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.
+
+#include "content/common/gpu/client/gpu_jpeg_decode_accelerator_host.h"
+
+#include "base/bind.h"
+#include "base/logging.h"
+#include "base/message_loop/message_loop.h"
+#include "base/synchronization/waitable_event.h"

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

not used?

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

Done.

+#include "content/common/gpu/client/gpu_channel_host.h"
+#include "content/common/gpu/gpu_messages.h"
+#include "ipc/ipc_message_macros.h"
+#include "ipc/ipc_message_utils.h"
+
+using media::JpegDecodeAccelerator;
+namespace content {
+
+GpuJpegDecodeAcceleratorHost::GpuJpegDecodeAcceleratorHost(
+    GpuChannelHost* channel,
+    int32 route_id,
+    const scoped_refptr<base::MessageLoopProxy>& io_message_loop)
+    : channel_(channel),
+      client_(NULL),
+      decoder_route_id_(route_id),
+      io_message_loop_(io_message_loop),
+      weak_this_factory_(this) {
+  DCHECK(channel_);
+}
+
+GpuJpegDecodeAcceleratorHost::~GpuJpegDecodeAcceleratorHost() {
+  DCHECK(CalledOnValidThread());
+
+  if (channel_ && decoder_route_id_ != MSG_ROUTING_NONE)
+    channel_->RemoveRoute(decoder_route_id_);
+}
+
+bool GpuJpegDecodeAcceleratorHost::OnMessageReceived(const IPC::Message& msg) {
+  DCHECK(io_message_loop_->BelongsToCurrentThread());
+  bool handled = true;
+  IPC_BEGIN_MESSAGE_MAP(GpuJpegDecodeAcceleratorHost, msg)
+    IPC_MESSAGE_HANDLER(AcceleratedJpegDecoderHostMsg_VideoFrameReady,
+                        OnVideoFrameReady)
+    IPC_MESSAGE_HANDLER(AcceleratedJpegDecoderHostMsg_NotifyError,
+                        OnNotifyError)
+    IPC_MESSAGE_UNHANDLED(handled = false)
+  IPC_END_MESSAGE_MAP()
+  DCHECK(handled);
+  // See OnNotifyError for why |this| mustn't be used after OnNotifyError might
+  // have been called above.
+  return handled;
+}
+
+void GpuJpegDecodeAcceleratorHost::OnChannelError() {
+  DVLOG(3) << __func__;
+  DCHECK(CalledOnValidThread());

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

io thread?

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

Done.

+  if (channel_) {
+    if (decoder_route_id_ != MSG_ROUTING_NONE)
+      channel_->RemoveRoute(decoder_route_id_);
+    channel_ = NULL;
+  }
+  PostNotifyError(kInvalidBitstreamBufferId, PLATFORM_FAILURE);
+}
+
+bool GpuJpegDecodeAcceleratorHost::Initialize(
+    media::JpegDecodeAccelerator::Client* client) {
+  DCHECK(CalledOnValidThread());
+
+  bool succeeded = false;
+  // This cannot be on IO thread because the msg is synchronous.
+  Send(new GpuMsg_CreateJpegDecoder(decoder_route_id_, &succeeded));
+
+  if (!succeeded) {
+    DLOG(ERROR) << "Send(GpuMsg_CreateJpegDecoder()) failed";
+    channel_->RemoveRoute(decoder_route_id_);
+    return false;
+  }
+  client_ = client;
+
+  return true;
+}
+
+void GpuJpegDecodeAcceleratorHost::Decode(
+    const media::BitstreamBuffer& bitstream_buffer,
+    const scoped_refptr<media::VideoFrame>& video_frame) {
+  DCHECK(CalledOnValidThread());

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

Isn't this io thread?

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

No, Decode() is called by GpuJpegDecoder::DecodeCapturedData() directly on
device thread.

+  if (!channel_)
+    return;
+
+  base::SharedMemoryHandle input_handle =
+      channel_->ShareToGpuProcess(bitstream_buffer.handle());
+  if (!base::SharedMemory::IsHandleValid(input_handle)) {
+    LOG(ERROR) << "Failed to duplicate buffer handle of BitstreamBuffer";
+    PostNotifyError(bitstream_buffer.id(), INVALID_ARGUMENT);
+    return;
+  }
+
+  if (!base::SharedMemory::IsHandleValid(video_frame->shared_memory_handle())) {
+    LOG(ERROR)
+        << "Decode(): cannot output to frame not backed by shared memory";
+    PostNotifyError(bitstream_buffer.id(), INVALID_ARGUMENT);
+    return;
+  }
+
+  base::SharedMemoryHandle output_handle =
+      channel_->ShareToGpuProcess(video_frame->shared_memory_handle());
+  if (!base::SharedMemory::IsHandleValid(output_handle)) {
+    LOG(ERROR) << "Decode(): failed to duplicate buffer handle of VideoFrame";
+    PostNotifyError(bitstream_buffer.id(), PLATFORM_FAILURE);
+    return;
+  }
+
+  size_t output_buffer_size = media::VideoFrame::AllocationSize(
+      video_frame->format(), video_frame->coded_size());
+
+  AcceleratedJpegDecoderMsg_Decode_Params decode_params;
+  decode_params.coded_size = video_frame->coded_size();
+  decode_params.input_buffer_id = bitstream_buffer.id();
+  decode_params.input_buffer_handle = input_handle;
+  decode_params.input_buffer_size = bitstream_buffer.size();
+  decode_params.output_video_frame_handle = output_handle;
+  decode_params.output_buffer_size = output_buffer_size;
+  Send(new AcceleratedJpegDecoderMsg_Decode(decoder_route_id_, decode_params));
+}
+
+void GpuJpegDecodeAcceleratorHost::Destroy() {
+  DCHECK(CalledOnValidThread());
+  if (channel_)
+    Send(new AcceleratedJpegDecoderMsg_Destroy(decoder_route_id_));
+  client_ = NULL;
+  delete this;
+}
+
+void GpuJpegDecodeAcceleratorHost::PostNotifyError(int32_t bitstream_buffer_id,
+                                                   Error error) {
+  DVLOG(2) << __func__ << ": error=" << error
+           << ", bitstream_buffer_id=" << bitstream_buffer_id;
+  DCHECK(CalledOnValidThread());

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

This is io thread.

[kcwu, 2015/04/30 19:25:41]

I modified to make PostNotifyError is only invoked in device thread and post
task to io thread.

+  // Post the error notification back to this thread, to avoid re-entrancy.

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

I still don't understand how re-entrancy is possible. I know OnNotifyError
better not to be called directly because Client::NotifyError() may Destroy()
|this|. If you cannot figure out the call flow of re-entrancy, I suggest change
the comments to the reason I mentioned.

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

Done.

+  base::MessageLoopProxy::current()->PostTask(

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

If InvalidateWeakPtrs is guaranteed to run on io thread as DCHECK shows in
OnNotifyError. We should use io_message_loop_ here to make sure the weak pointer
is dereferenced on io thread.

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

Done.

+      FROM_HERE,
+      base::Bind(&GpuJpegDecodeAcceleratorHost::OnNotifyError,
+                 weak_this_factory_.GetWeakPtr(), bitstream_buffer_id, error));
+}
+
+void GpuJpegDecodeAcceleratorHost::Send(IPC::Message* message) {
+  DVLOG(3) << __func__;
+  DCHECK(CalledOnValidThread());
+  uint32 message_type = message->type();
+  if (!channel_->Send(message)) {
+    DLOG(ERROR) << "Send(" << message_type << ") failed";

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

use message->type() directly

[kcwu, 2015/04/30 19:25:41]

Done.

+  }
+}
+
+void GpuJpegDecodeAcceleratorHost::OnVideoFrameReady(
+    int32_t bitstream_buffer_id) {
+  DCHECK(io_message_loop_->BelongsToCurrentThread());
+

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

remove blank line

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

Done.

+  DCHECK(client_);
+  client_->VideoFrameReady(bitstream_buffer_id);
+}
+
+void GpuJpegDecodeAcceleratorHost::OnNotifyError(int32_t bitstream_buffer_id,
+                                                 Error error) {
+  DCHECK(io_message_loop_->BelongsToCurrentThread());
+  if (!client_)

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

I'm not sure if this is OK to access |client_| from different threads in
OnNotifyError and Destroy. Please look at the code and explain why this is OK.

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

Removed code about |client_| in Destroy.

+    return;
+  weak_this_factory_.InvalidateWeakPtrs();
+
+  // Client::NotifyError() may Destroy() |this|, so calling it needs to be the
+  // last thing done on this stack!
+  media::JpegDecodeAccelerator::Client* client = NULL;
+  std::swap(client, client_);
+  client->NotifyError(bitstream_buffer_id,
+                      static_cast<media::JpegDecodeAccelerator::Error>(error));
+}
+
+}  // namespace content