[FFmpeg-trac] #4437(avdevice:open): AVFoundation recording has consistent intermittent frame drops

FFmpeg trac at avcodec.org
Mon Sep 19 14:58:51 EEST 2016


#4437: AVFoundation recording has consistent intermittent frame drops
-------------------------------------+-------------------------------------
             Reporter:  LordHDL      |                    Owner:  mateo
                 Type:  defect       |                   Status:  open
             Priority:  normal       |                Component:  avdevice
              Version:  git-master   |               Resolution:
             Keywords:               |               Blocked By:
  avfoundation bounty                |  Reproduced by developer:  1
             Blocking:               |
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------

Comment (by LordHDL):

 All right so I have yet ''more'' information that might be helpful.  I
 have these 2 videos recorded via Syphon Recorder (couldn't use PixelToy
 because it didn't work with Syphon Inject):

 (Ignore registration prompt and download directly.)

 https://www.dropbox.com/s/2wg1hwydxomdgaa/60.mkv?dl=0
 https://www.dropbox.com/s/l56iuma9hrz9uum/AFAP.mkv?dl=0

 The first one is very similar to the videos I get when recording using
 ffmpeg.  The second is perfectly smooth.  The difference is in choosing a
 number frame rate versus "As Fast As Possible" in the preferences.  Here
 are their average rates respectively:

 [[Image(https://puu.sh/rgumQ/57d2f5abed.png)]]
 [[Image(https://puu.sh/rgumk/7e86c11bd3.png)]]

 The source in question does not run higher than 60 FPS anyway, so choosing
 "As Fast As Possible" nets every possible frame it can deliver, resulting
 in a perfect video.

 Is there a way to set ffmpeg to record "as fast as possible" with
 AVFoundation screen capture?  I think that may be a good workaround for
 this issue for the time being.

--
Ticket URL: <https://trac.ffmpeg.org/ticket/4437#comment:41>
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