Decouple capture timestamp and reference time

content/browser/renderer_host/media/video_capture_gpu_jpeg_decoder.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/browser/renderer_host/media/video_capture_gpu_jpeg_decoder.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 61 matching lines @@
     const {
   DCHECK(CalledOnValidThread());
   base::AutoLock lock(lock_);
   return decoder_status_;
 }
 
 void VideoCaptureGpuJpegDecoder::DecodeCapturedData(
     const uint8_t* data,
     size_t in_buffer_size,
     const media::VideoCaptureFormat& frame_format,
-    const base::TimeTicks& timestamp,
+    base::TimeTicks reference_time,
+    base::TimeDelta timestamp,
     std::unique_ptr<media::VideoCaptureDevice::Client::Buffer> out_buffer) {
   DCHECK(CalledOnValidThread());
   DCHECK(decoder_);
 
   TRACE_EVENT_ASYNC_BEGIN0("jpeg", "VideoCaptureGpuJpegDecoder decoding",
                            next_bitstream_buffer_id_);
   TRACE_EVENT0("jpeg", "VideoCaptureGpuJpegDecoder::DecodeCapturedData");
 
   // TODO(kcwu): enqueue decode requests in case decoding is not fast enough
   // (say, if decoding time is longer than 16ms for 60fps 4k image)
@@ skipping 33 matching lines @@
   scoped_refptr<media::VideoFrame> out_frame =
       media::VideoFrame::WrapExternalSharedMemory(
           media::PIXEL_FORMAT_I420,                   // format
           dimensions,                                 // coded_size
           gfx::Rect(dimensions),                      // visible_rect
           dimensions,                                 // natural_size
           static_cast<uint8_t*>(out_buffer->data()),  // data
           out_buffer->mapped_size(),                  // data_size
           out_handle,                                 // handle
           0,                                          // shared_memory_offset
-          base::TimeDelta());                         // timestamp
+          timestamp);                                 // timestamp
   if (!out_frame) {
     base::AutoLock lock(lock_);
     decoder_status_ = FAILED;
     LOG(ERROR) << "DecodeCapturedData: WrapExternalSharedMemory failed";
     return;
   }
   out_frame->metadata()->SetDouble(media::VideoFrameMetadata::FRAME_RATE,
                                    frame_format.frame_rate);
 
   {
     base::AutoLock lock(lock_);
     decode_done_closure_ = base::Bind(
-        decode_done_cb_, base::Passed(&out_buffer), out_frame, timestamp);
+        decode_done_cb_, base::Passed(&out_buffer), out_frame, reference_time);

[miu, 2016/06/07 20:03:47]

ditto: Just set out_frame->metadata()->SetTimeTicks(...) instead of needing an
extra argument here.

[qiangchen, 2016/06/08 18:04:30]

Done.

   }
   decoder_->Decode(in_buffer, out_frame);
 #else
   NOTREACHED();
 #endif
 }
 
 void VideoCaptureGpuJpegDecoder::VideoFrameReady(int32_t bitstream_buffer_id) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   TRACE_EVENT0("jpeg", "VideoCaptureGpuJpegDecoder::VideoFrameReady");
@@ skipping 88 matching lines @@
   lock_.AssertAcquired();
   return !decode_done_closure_.is_null();
 }
 
 void VideoCaptureGpuJpegDecoder::RecordInitDecodeUMA_Locked() {
   UMA_HISTOGRAM_BOOLEAN("Media.VideoCaptureGpuJpegDecoder.InitDecodeSuccess",
                         decoder_status_ == INIT_PASSED);
 }
 
 }  // namespace content