[FFmpeg-trac] #4030(avdevice:open): V4L2 recording results in invalid data & buffer still owned errors

FFmpeg trac at avcodec.org
Wed Oct 22 12:41:38 CEST 2014

#4030: V4L2 recording results in invalid data & buffer still owned errors
             Reporter:  thender     |                    Owner:  holden
                 Type:  defect      |                   Status:  open
             Priority:  normal      |                Component:  avdevice
              Version:  git-master  |               Resolution:
             Keywords:  v4l2        |               Blocked By:
             Blocking:              |  Reproduced by developer:  0
Analyzed by developer:  1           |

Comment (by holden):

 Thanks for your feedback. Some comments:

 1) Please test the following command, this will tell us what the hardware
 actually supports:

 ffmpeg -f video4linux2 -list_formats all -i /dev/video0

 2) -s is not a v4l2 device option. You can read about all the valid
 options here:
 the valid command line would be:

 ffmpeg -loglevel debug -f v4l2 -framerate 30 -video_size 1920x1080 -i
 /dev/video2 -c:v libx264 -preset ultrafast -crf 10 microcorder.mkv

 Does the problem still exist with using this command? Also, as Carl
 suggested, test with a smaller resolution.

 Replying to [comment:19 thender]:
 > If it would help a developer to resolve this issue I would be happy to
 provide one of these capture devices & also a portable camcorder with hdmi
 output to you so you can try for yourself. Let me know if you would like
 to take me up on this offer. I am not a developer or manufacturer, just an
 end user that really likes ffmpeg. I have an extra one of these that
 works, and also a portable camcorder I never use. It would be more than
 sufficient, all you would need is a computer with a good USB 3.0 port to
 do the testing.

 That would help a lot, yes, so if we can't solve the issue I might take
 you up on that offer. Also, having a box with remote ssh access would help
 as an alternative. If you're on IRC ping me sometime (my nick is Holden),
 I could ask you to do some tests in real time and maybe we could get this
 fixed faster.

Ticket URL: <https://trac.ffmpeg.org/ticket/4030#comment:21>
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