[Libav-user] Recent ffmpeg version doesn't support v4l2

[Alex Cohn]

Could this be related to the requirement to build ffmpeg as superuser?
Alex

On Saturday, June 18, 2011, Leandro Santiago <leandrosansilva at gmail.com> wrote:
> Hello to all.
>
> Some days ago, after I got lastest ffmpeg source, ffmpeg stoped to
> work with my v4l2 cameras. They're using the bttv module (ubuntu 10.10
> ia32).
>
> The ffplay's output:
>
> $ ./ffplay -f video4linux2 /dev/video0
> ffplay version git-N-30818-g369c68c, Copyright (c) 2003-2011 the
> FFmpeg developers
>  built on Jun 17 2011 12:16:37 with gcc 4.4.5
>  configuration: --disable-gpl --enable-static --enable-libvpx
> --disable-libschroedinger --disable-libtheora
> --prefix=/home/devstar22/projects/build_optm --enable-pthreads
> --extra-cflags='-I/home/devstar22/projects/build_optm/include -O3
> -msse3 -mfpmath=sse -march=core2' --enable-extra-warnings
> --extra-ldflags=-L/home/devstar22/projects/build_optm/lib
>  libavutil    51.  8. 0 / 51.  8. 0
>  libavcodec   53.  7. 0 / 53.  7. 0
>  libavformat  53.  3. 1 / 53.  3. 1
>  libavdevice  53.  1. 1 / 53.  1. 1
>  libavfilter   2. 18. 0 /  2. 18. 0
>  libswscale    0. 14. 1 /  0. 14. 1
> [video4linux2 @ 0x95d57a0] ioctl set time per frame(1/25) failed
> [video4linux2 @ 0x95d57a0] Could not find codec parameters (Invalid
> Codec type -1)
> [video4linux2 @ 0x95d57a0] Estimating duration from bitrate, this may
> be inaccurate
> /dev/video0: could not find codec parameters
>
> Why does it happen? Have you broken the v4l2 support? I'm sure ffmpeg
> was compiled with v4l2 support, so I really don't know why it happens.
>
> That behavior also happens in my application, using libavformat api.
> When I open the device passing a AVInputFormat correct confiured to
> input "video4linux2", the call av_open_input_file has success (returns
> 0), but prints on screen:
>
> [video4linux2 @ 0x95d57a0] ioctl set time per frame(1/25) failed
>
> And when I call av_find_stream_info(), it returns the -1 code and
> print on screen:
>
> [video4linux2 @ 0x95d57a0] Could not find codec parameters (Invalid
> Codec type -1)
> [video4linux2 @ 0x95d57a0] Estimating duration from bitrate, this may
> be inaccurate
>
> Obs: when I use the ffplay and libav* libraries installed globally in
> the system (via ubuntu repositories), ffplay opens the cameras
> normally.
>
> Best wishes.
> _______________________________________________
> Libav-user mailing list
> Libav-user at ffmpeg.org
> http://ffmpeg.org/mailman/listinfo/libav-user
>