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

[Leandro Santiago]

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.