Mac Video Capture: Sending the timestamps provided by the driver to the capture pipeline

media/capture/video/mac/video_capture_device_qtkit_mac.mm

 // Copyright (c) 2012 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.
 
 #import "media/capture/video/mac/video_capture_device_qtkit_mac.h"
 
 #import <QTKit/QTKit.h>
 
 #include "base/debug/crash_logging.h"
 #include "base/logging.h"
@@ skipping 306 matching lines @@
           aspectRatioDict, kCVImageBufferPixelAspectRatioHorizontalSpacingKey);
       CFNumberRef aspectDenominatorRef = (CFNumberRef)CFDictionaryGetValue(
           aspectRatioDict, kCVImageBufferPixelAspectRatioVerticalSpacingKey);
       DCHECK(aspectNumeratorRef && aspectDenominatorRef)
           << "Aspect Ratio dictionary missing its entries.";
       CFNumberGetValue(aspectNumeratorRef, kCFNumberIntType, &aspectNumerator);
       CFNumberGetValue(aspectDenominatorRef, kCFNumberIntType,
                        &aspectDenominator);
     }
 
+    QTTime qt_timestamp = [sampleBuffer presentationTime];

[mcasas, 2015/10/31 03:24:25]

const

[qiangchen, 2015/11/02 18:21:21]

Done.

     // Deliver the captured video frame.
+    const int microseconds_per_second = 1000000;
+    const base::TimeTicks timestamp =
+        base::TimeTicks() +
+        base::TimeDelta::FromMicroseconds(qt_timestamp.timeValue *
+                                          microseconds_per_second /
+                                          qt_timestamp.timeScale);
     frameReceiver_->ReceiveFrame(addressToPass, frameSize, captureFormat,
-                                 aspectNumerator, aspectDenominator);
+                                 aspectNumerator, aspectDenominator, timestamp);
 
     CVPixelBufferUnlockBaseAddress(videoFrame, kLockFlags);
   }
   [lock_ unlock];
 }
 
 - (void)handleNotification:(NSNotification*)errorNotification {
   NSError* error = (NSError*)
       [[errorNotification userInfo] objectForKey:QTCaptureSessionErrorKey];
   [self sendErrorString:
@@ skipping 11 matching lines @@
 
 - (void)sendLogString:(NSString*)message {
   DVLOG(1) << [message UTF8String];
   [lock_ lock];
   if (frameReceiver_)
     frameReceiver_->LogMessage([message UTF8String]);
   [lock_ unlock];
 }
 
 @end