Send bytes_used of v4l2 captured frame when video capture

media/video/capture/linux/v4l2_capture_delegate_multi_plane.cc

Index: media/video/capture/linux/v4l2_capture_delegate_multi_plane.cc
diff --git a/media/video/capture/linux/v4l2_capture_delegate_multi_plane.cc b/media/video/capture/linux/v4l2_capture_delegate_multi_plane.cc
index 7551bed434c7f7b5603a12bb842715616aa95e00..61839b142a76b95849291e586a6944d3a656e416 100644
--- a/media/video/capture/linux/v4l2_capture_delegate_multi_plane.cc
+++ b/media/video/capture/linux/v4l2_capture_delegate_multi_plane.cc
@@ -57,7 +57,8 @@ void V4L2CaptureDelegateMultiPlane::FinishFillingV4L2Buffer(
 
 void V4L2CaptureDelegateMultiPlane::SendBuffer(
     const scoped_refptr<BufferTracker>& buffer_tracker,
-    const v4l2_format& format) const {
+    const v4l2_format& format,
+    size_t /*bytes_used*/) const {

[wuchengli, 2015/05/19 04:05:54]

From the v4l2 documentation, bytesused is ignored for multiplanar. So this value
doesn't make sense for 4L2CaptureDelegateMultiPlane. I think you can add
V4L2CaptureDelegate::BufferTracker::GetBytesused(size_t plane) and
V4L2CaptureDelegate::BufferTracker::Plane::bytesused. You won't need to add
|bytes_used| to SendBuffer.

http://linuxtv.org/downloads/v4l-dvb-apis/buffer.html

[wuchengli, 2015/05/19 04:18:51]

Kuang-che told me bytesused is different for every frame and BufferTracker is
initialized only once. So how about passing a |bytesused| array to SendBuffer()
in V4L2CaptureDelegate::DoCapture()? 
__u32 bytesused[VIDEO_MAX_PLANES];
if (video_fmt_.type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
  bytesused[0] = buffer.bytesused;
else
  for (i = 0; i < video_fmt_.pix_mp.num_planes; i++)
    bytesused[i] = buffer.m.planes[i].bytesused;

[Pawel Osciak, 2015/05/20 07:29:02]

Personally I liked the idea to add this to BufferTracker. What do you think
about adding a plane_payload[] array to BufferTracker and a setter/getter
SetPlanePayload()/GetPlanePayload()?

[kcwu, 2015/05/20 12:14:52]

Done.

   DCHECK_EQ(capture_format().pixel_format, PIXEL_FORMAT_I420);
   const size_t y_stride = format.fmt.pix_mp.plane_fmt[0].bytesperline;
   const size_t u_stride = format.fmt.pix_mp.plane_fmt[1].bytesperline;