[FFmpeg-user] recording @ 120fps on mac fails with 'activeVideoMinFrameDuration not supported'

[Roman Puttkammer]

On Wed, Nov 15, 2017 at 10:48 AM Carl Eugen Hoyos <ceffmpeg at gmail.com>
wrote:

> 2017-11-15 4:58 GMT+01:00 Roman Puttkammer <rputtkammer at gmail.com>:
> > I did run into another issue; though the frame rate 320/240 @ 120fps is
> set
> > successfully, ffmpeg reports only 30+ fps later on.
>
> Please test without encoding to analyse whether this is a performance
> issue:
> $ ffmpeg -f avfoundation -video_size 320x240 -r 120.101366 -pixel_format
> uyvy422
> -i "0:none" -f null -
>
> The status line will tell you the actual reading speed.
>

Carl - thanks. Running the test, the status line says fps=34 and speed
0.297 (see below.) What are the
hardware bottlenecks? It doesn't seem to be the CPU which remains 90% or
more idle.

(I noticed you suggested -r 120 as opposed to -framerate 120. If I use
-framerate, fps remains similar but
the speed shows a value > 1.)

*Romans-MBP:ffmpeg putt$ ffmpeg/ffmpeg -f avfoundation -video_size 320x240
-r 120.101366 -pixel_format uyvy422 -i "0:none" -f null -*
Input #0, avfoundation, from '0:none':
  Duration: N/A, start: 1748.307600, bitrate: N/A
    Stream #0:0: Video: rawvideo (UYVY / 0x59565955), uyvy422, 320x240, 33
tbr, 1000k tbn, 1000k tbc
Stream mapping:
  Stream #0:0 -> #0:0 (rawvideo (native) -> wrapped_avframe (native))
Press [q] to stop, [?] for help
Output #0, null, to 'pipe:':
  Metadata:
    encoder         : Lavf58.2.100
    Stream #0:0: Video: wrapped_avframe, uyvy422, 320x240, q=2-31, 200
kb/s, 120.10 fps, 120.10 tbn, 120.10 tbc
    Metadata:
      encoder         : Lavc58.3.101 wrapped_avframe
*frame=  311 fps= 36 q=-0.0 size=N/A time=00:00:02.58 bitrate=N/A
speed=0.297x    *