tree 909e4601097f43b0db808361964187e08b42eb1a
parent 39ddafe609b727b752ee2a2051f3cb7e74bb53be
author Chen-Hao Chang@google.com <haocc@google.com> 1471333463 +0800
committer chrome-bot <chrome-bot@chromium.org> 1471507461 -0700

Add an audio/video synchronization utility

On Chameleon, audio capturing and video capturing work separately.
To know the time difference between audio/video capturing, we can
monitor the changes of the audio page count and the video frame count.

BUG=None
TEST=manual test.
  Use test_server to test StartMonitoringAudioVideoCapturingDelay() and
  GetAudioVideoCapturingDelay(), note that the edid should be equipped
  with audio.
  >>> for i in xrange(10):
  ...   p.StartMonitoringAudioVideoCapturingDelay()
  ...   p.StartCapturingVideo(3)
  ...   p.StartCapturingAudio(3)
  ...   time.sleep(2)
  ...   p.StopCapturingVideo()
  ...   p.StopCapturingAudio(3)
  ...   print p.GetAudioVideoCapturingDelay()
  ...

Change-Id: I9b213964afed51a2e9c7b9c56ddc8b6002ef73bd
Reviewed-on: https://chromium-review.googlesource.com/371158
Commit-Ready: Chen-hao Chang <haocc@google.com>
Tested-by: Chen-hao Chang <haocc@google.com>
Reviewed-by: Wai-Hong Tam <waihong@google.com>