Decouple capture timestamp and reference time

content/browser/renderer_host/media/video_capture_device_client.cc

Index: content/browser/renderer_host/media/video_capture_device_client.cc
diff --git a/content/browser/renderer_host/media/video_capture_device_client.cc b/content/browser/renderer_host/media/video_capture_device_client.cc
index cf6ad3a98149ed256c83dce37eb3a833c8426cf4..974be109fe7ff895df5008e3a4ad6e93c0ee3e2f 100644
--- a/content/browser/renderer_host/media/video_capture_device_client.cc
+++ b/content/browser/renderer_host/media/video_capture_device_client.cc
@@ -85,7 +85,8 @@ void VideoCaptureDeviceClient::OnIncomingCapturedData(
     int length,
     const VideoCaptureFormat& frame_format,
     int rotation,
-    const base::TimeTicks& timestamp) {
+    base::TimeTicks reference_time,
+    base::TimeDelta timestamp) {
   TRACE_EVENT0("video", "VideoCaptureDeviceClient::OnIncomingCapturedData");
   DCHECK_EQ(media::PIXEL_STORAGE_CPU, frame_format.pixel_storage);
 
@@ -224,8 +225,9 @@ void VideoCaptureDeviceClient::OnIncomingCapturedData(
     } else if (status == VideoCaptureGpuJpegDecoder::INIT_PASSED &&
         frame_format.pixel_format == media::PIXEL_FORMAT_MJPEG &&
         rotation == 0 && !flip) {
-      external_jpeg_decoder_->DecodeCapturedData(data, length, frame_format,
-                                                 timestamp, std::move(buffer));
+      // TODO(qiangchen): Pass timestamp into DecodeCapturedData.
+      external_jpeg_decoder_->DecodeCapturedData(
+          data, length, frame_format, reference_time, std::move(buffer));
       return;
     }
   }
@@ -254,7 +256,8 @@ void VideoCaptureDeviceClient::OnIncomingCapturedData(
   const VideoCaptureFormat output_format = VideoCaptureFormat(
       dimensions, frame_format.frame_rate,
       media::PIXEL_FORMAT_I420, output_pixel_storage);
-  OnIncomingCapturedBuffer(std::move(buffer), output_format, timestamp);
+  OnIncomingCapturedBuffer(std::move(buffer), output_format, reference_time,
+                           timestamp);
 }
 
 std::unique_ptr<media::VideoCaptureDevice::Client::Buffer>
@@ -287,7 +290,8 @@ VideoCaptureDeviceClient::ReserveOutputBuffer(
 void VideoCaptureDeviceClient::OnIncomingCapturedBuffer(
     std::unique_ptr<Buffer> buffer,
     const VideoCaptureFormat& frame_format,
-    const base::TimeTicks& timestamp) {
+    base::TimeTicks reference_time,
+    base::TimeDelta timestamp) {
   // Currently, only I420 pixel format is supported.
   DCHECK_EQ(media::PIXEL_FORMAT_I420, frame_format.pixel_format);
 
@@ -319,22 +323,21 @@ void VideoCaptureDeviceClient::OnIncomingCapturedBuffer(
     return;
   frame->metadata()->SetDouble(media::VideoFrameMetadata::FRAME_RATE,
                                frame_format.frame_rate);
-  OnIncomingCapturedVideoFrame(std::move(buffer), frame, timestamp);
+  frame->set_timestamp(timestamp);

[miu, 2016/05/25 01:51:30]

nit: Instead of calling set_timestamp() here, you should pass it as the last
argument (i.e., instead of base::TimeDelta()) to the VideoFrame::WrapXXX() calls
above.

[qiangchen, 2016/05/25 16:46:17]

Done.

+  OnIncomingCapturedVideoFrame(std::move(buffer), frame, reference_time);
 }
 
 void VideoCaptureDeviceClient::OnIncomingCapturedVideoFrame(
     std::unique_ptr<Buffer> buffer,
     const scoped_refptr<VideoFrame>& frame,
-    const base::TimeTicks& timestamp) {
+    base::TimeTicks reference_time) {
+  // TODO(qiangchen): Dive into DoIncomingCapturedVideoFrameOnIOThread to
+  // process timestamp.
   BrowserThread::PostTask(
-      BrowserThread::IO,
-      FROM_HERE,
+      BrowserThread::IO, FROM_HERE,
       base::Bind(
           &VideoCaptureController::DoIncomingCapturedVideoFrameOnIOThread,
-          controller_,
-          base::Passed(&buffer),
-          frame,
-          timestamp));
+          controller_, base::Passed(&buffer), frame, reference_time));
 }
 
 std::unique_ptr<media::VideoCaptureDevice::Client::Buffer>