[PPAPI] Implement media stream video track API

content/renderer/pepper/pepper_media_stream_video_track_host.cc

+// Copyright (c) 2014 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/renderer/pepper/pepper_media_stream_video_track_host.h"
+
+#include "ppapi/c/pp_errors.h"
+#include "ppapi/c/ppb_video_frame.h"
+#include "ppapi/shared_impl/media_stream_frame.h"
+
+using media::VideoFrame;
+
+namespace {
+
+// TODO(penghuang): make it configurable.
+const int32_t kNumberOfFrames = 4;
+
+PP_VideoFrame_Format ToPpapiFormat(VideoFrame::Format format) {
+  switch (format) {
+  case VideoFrame::YV12:
+    return PP_VIDEOFRAME_FORMAT_YV12;
+  case VideoFrame::YV16:
+    return PP_VIDEOFRAME_FORMAT_YV16;
+  case VideoFrame::I420:
+    return PP_VIDEOFRAME_FORMAT_I420;
+  case VideoFrame::YV12A:
+    return PP_VIDEOFRAME_FORMAT_YV12A;
+  case VideoFrame::YV12J:
+    return PP_VIDEOFRAME_FORMAT_YV12J;
+  default:
+    DVLOG(1) << "Unsupported pixel format " << format;
+    return PP_VIDEOFRAME_FORMAT_UNKNOWN;
+  }
+}
+
+}  // namespace
+
+namespace content {
+
+PepperMediaStreamVideoTrackHost::PepperMediaStreamVideoTrackHost(
+    RendererPpapiHost* host,
+    PP_Instance instance,
+    PP_Resource resource,
+    const blink::WebMediaStreamTrack& track)
+    : PepperMediaStreamTrackHostBase(host, instance, resource),
+      track_(track),
+      connected_(false),
+      frame_format_(VideoFrame::UNKNOWN),
+      frame_data_size_(0) {
+  DCHECK(!track_.isNull());
+}
+
+PepperMediaStreamVideoTrackHost::~PepperMediaStreamVideoTrackHost() {
+  OnClose();
+}
+
+void PepperMediaStreamVideoTrackHost::OnClose() {
+  if (connected_) {
+    MediaStreamVideoSink::RemoveFromVideoTrack(this, track_);
+    connected_ = false;
+  }
+}
+
+void PepperMediaStreamVideoTrackHost::OnVideoFrame(
+    const scoped_refptr<VideoFrame>& frame) {
+  DCHECK(frame);
+  PP_VideoFrame_Format ppformat = ToPpapiFormat(frame->format());
+  if (ppformat == PP_VIDEOFRAME_FORMAT_UNKNOWN)
+    return;
+
+  if (frame_size_ != frame->coded_size() || frame_format_ != frame->format()) {
+    frame_size_ = frame->coded_size();
+    frame_format_ = frame->format();
+    // TODO(penghuang): Support changing |frame_size_| & |frame_format_| more
+    // than once.
+    DCHECK(!frame_data_size_);
+    frame_data_size_ = VideoFrame::AllocationSize(frame_format_, frame_size_);
+    int32_t size = sizeof(ppapi::MediaStreamFrame::Video) + frame_data_size_;
+    InitFrames(kNumberOfFrames, size);
+  }
+
+  int32_t index = frame_buffer()->DequeueFrame();
+  // Drop frames if the underlying buffer is empty.
+  if (index < 0)
+    return;
+
+  ppapi::MediaStreamFrame::Video* ppframe =
+    &(frame_buffer()->GetFramePointer(index)->video);
+  ppframe->header.size = frame_buffer()->frame_size();
+  ppframe->header.type = ppapi::MediaStreamFrame::TYPE_VIDEO;
+  ppframe->timestamp = frame->GetTimestamp().InSecondsF();
+  ppframe->format = ppformat;
+  ppframe->size.width = frame->coded_size().width();
+  ppframe->size.height = frame->coded_size().height();
+  ppframe->data_size = frame_data_size_;
+
+  COMPILE_ASSERT(VideoFrame::kYPlane == 0, y_plane_should_be_0);
+  COMPILE_ASSERT(VideoFrame::kUPlane == 1, u_plane_should_be_1);
+  COMPILE_ASSERT(VideoFrame::kVPlane == 2, v_plane_should_be_2);
+
+  uint8_t* dst = ppframe->data;
+  for (size_t i = 0; i < VideoFrame::NumPlanes(frame->format()); ++i) {

[dmichael (off chromium), 2014/01/09 21:06:47]

It's a shame we have to do this copy stuff. It would be nice if we had a way to
integrate with the MediaStreamTrack/VideoFrame stuff to somehow say "Here's the
memory you should use".

Possible future work?

[Peng, 2014/01/10 19:14:30]

As my understanding, blink::MediaStreamTrack supports adding more than one sinks
to it. So it has to create a frame and call every sinks' OnVideoFrame() with the
same frame. :(

+    const uint8_t* src = frame->data(i);
+    const size_t row_bytes = frame->row_bytes(i);
+    const size_t src_stride = frame->stride(i);
+    for (int j = 0; j < frame->rows(i); ++j) {
+      memcpy(dst, src, row_bytes);
+      dst += row_bytes;
+      src += src_stride;
+    }
+  }
+  PluginEnqueueFrame(index);
+}
+
+void PepperMediaStreamVideoTrackHost::DidConnectPendingHostToResource() {
+  if (!connected_) {
+    MediaStreamVideoSink::AddToVideoTrack(this, track_);
+    connected_ = true;
+  }
+}
+
+}  // namespace content