[FFmpeg-user] video4linux2 framerate

kqt4at5v at gmail.com kqt4at5v at gmail.com
Wed Apr 30 15:23:12 CEST 2014


I know I will get flamed for referring to a specific distribution but I 
think it is irrelevant. Previously using ffmpeg package in Ubuntu 10.04 I 
used "ffmpeg -f video4linux2 -s 640x480 -r 1 -i /dev/${CAMERA} -an ${CAPTURE_DIR}/\%05d.jpg"
to get 1 frame per second. I upgraded to Ubuntu 12.04 and It is broken.

ffmpeg version 0.8.10-4:0.8.10-0ubuntu0.12.04.1, Copyright (c) 2000-2013 the Libav developers
   built on Feb  6 2014 20:59:08 with gcc 4.6.3
*** THIS PROGRAM IS DEPRECATED ***
This program is only provided for compatibility and will be removed in a 
future release. Please use avconv instead.
[video4linux2 @ 0x8997aa0] ioctl set time per frame(1/1) failed
[video4linux2 @ 0x8997aa0] ioctl(VIDIOC_DQBUF): Invalid argument
[video4linux2 @ 0x8997aa0] decoding for stream 0 failed
[video4linux2 @ 0x8997aa0] Estimating duration from bitrate, this may be inaccurate
/dev/shop: could not find codec parameters

I tried avconv and got the same error. I compiled the latest tarball from 
ffmpeg.org, ffmpeg-2.2.1.tar.bz2,

ffmpeg version 2.2.1 Copyright (c) 2000-2014 the FFmpeg developers  built on Apr 29 2014 13:33:50 with gcc 4.6 (Ubuntu/Linaro 
4.6.3-1ubuntu5)
   configuration: --prefix=/home/rray/ffmpeg-2.2.1
   libavutil      52. 66.100 / 52. 66.100
   libavcodec     55. 52.102 / 55. 52.102
   libavformat    55. 33.100 / 55. 33.100
   libavdevice    55. 10.100 / 55. 10.100
   libavfilter     4.  2.100 /  4.  2.100
   libswscale      2.  5.102 /  2.  5.102
   libswresample   0. 18.100 /  0. 18.100
[video4linux2,v4l2 @ 0xb073dc0] The driver does not allow to change time per frame
Input #0, video4linux2,v4l2, from '/dev/shop':
   Duration: N/A, start: 1398864022.798506, bitrate: 92160 kb/s
     Stream #0:0: Video: rawvideo (I420 / 0x30323449), yuv420p, 640x480, 
92160 kb/s, 25 fps, 25 tbr, 1000k tbn, 1000k tbc
[swscaler @ 0xb062040] deprecated pixel format used, make sure you did set range correctly
Output #0, image2, to '/backup_1/camera/20140430/shop_082021/%05d.jpg':
   Metadata:
     encoder         : Lavf55.33.100
     Stream #0:0: Video: mjpeg, yuvj420p, 640x480, q=2-31, 200 kb/s, 90k tbn, 1 tbc
Stream mapping:
   Stream #0:0 -> #0:0 (rawvideo -> mjpeg)
Press [q] to stop, [?] for help
frame=   22 fps= 15 q=24.8 Lsize=N/A time=00:00:22.00 bitrate=N/A
video:1407kB audio:0kB subtitle:0 data:0 global headers:0kB muxing overhead -100.001526%


It records but runs at 15 fps, I guess this is why "The driver does not 
allow to change time per frame". So my question is how can I record 1 fps?

Thanks
Richard



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