[FFmpeg-user] problem with FFMPEG and USB WEBCAM: max resolution
Carl Eugen Hoyos
cehoyos at ag.or.at
Sat Jun 18 16:35:47 CEST 2016
Juan M. Anera <juasmilla <at> gmail.com> writes:
> ffmpeg version 3.0.2-2~bpo8+1
Please understand that generally only current FFmpeg git head
is supported on this mailing list.
> ffmpeg -y -f alsa -i hw:1 -i /dev/video0 -t 10 out12.avi
This is missing -qscale 2 or -qscale 10 or -vb 2000
(which is the reason for the bad quality).
> Input #0, alsa, from 'hw:1':
> Duration: N/A, start: 1466107437.084808, bitrate: 1024 kb/s
> Input #1, video4linux2,v4l2, from '/dev/video0':
> Duration: N/A, start: 1578.347093, bitrate: 147456 kb/s
The different start times mean that no recording can be in-sync.
Try the different sync options for v4l2, namely -ts abs or
-ts mono2abs.
To set the resolution, use the -video_size option.
See ffmpeg -h demuxer=v4l2 to learn about the options.
Carl Eugen
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