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

[FFmpeg]

#4437: AVFoundation recording has consistent intermittent frame drops
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             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            |
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Comment (by thilo.borgmann):

 For the audio:

 I forgot to mentioned there are new options for that.
 "-list_audio_formats true" shows the formats available.
 "-audio_format_index N" selects the one you want.
 I tested with my phone connected to line-in and it works for me with any
 of the formats given there (which are not marked as unsupported).
 Please post the output of -list_audio_formats here and try some another
 formats for recording - static (silence) seems to be just another problem
 I did only encounter with microphone so far.

 For the video:

 I don't see any problems in the first few hundred frames, visually
 checked.
 However, there are duplicated frames like 790-791. This looks to me that
 the applications window was not redrawn by the window server. I encounter
 similar behaviour when capturing the entire screen where some parts were
 redrawn while the 60fps application shows the very same pixels. The PTS
 timestamps from the Apple provided sample buffers show different values in
 these cases. Thus I think that it is not the case that ffmpeg is loosing
 frames for latency somewhere.

 To prove this assumption, another capture of more than one 60fps
 application should be helpful. Is this application you're using somehting
 I can download for free somewhere (are you actually playing or is it a
 self-running demo)? I would like to capture it next to PixelToy to be sure
 that there is nothing more we could do here.

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Ticket URL: <https://trac.ffmpeg.org/ticket/4437#comment:30>
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