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

[Leandro Santiago]

I don't now...
Today I tried to compile three different versions of ffmpeg and test
them: 0.6.3, 0.7-rc1 and from master branch.

I didn't try to compile my application with version 0.6 (it uses newer
libav* API), but the ffplay, using the command...

$ ./ffplay -f video4linux2 /dev/video2

... worked only with ffmpeg 0.6 series. Here are the output:

devstar22 at devstar22-desktop:~/projects/3rd/ffmpeg-0.6.3$ ./ffplay -f
video4linux2 /dev/video2
FFplay version 0.6.3, Copyright (c) 2003-2010 the FFmpeg developers
  built on Jun 20 2011 09:01:12 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'
--enable-extra-warnings
--extra-ldflags=-L/home/devstar22/projects/build_optm/lib/
  libavutil     50.15. 1 / 50.15. 1
  libavcodec    52.72. 2 / 52.72. 2
  libavformat   52.64. 2 / 52.64. 2
  libavdevice   52. 2. 0 / 52. 2. 0
  libswscale     0.11. 0 /  0.11. 0
[video4linux2 @ 0x8eed640]Estimating duration from bitrate, this may
be inaccurate
Input #0, video4linux2, from '/dev/video2':
  Duration: N/A, start: 1308571289.499852, bitrate: 92160 kb/s
    Stream #0.0: Video: rawvideo, yuv420p, 640x480, 92160 kb/s, 25
tbr, 1000k tbn, 25 tbc
^C^C^Z1298.78 A-V:  0.000 s:0.4 aq=    0KB vq=    0KB sq=    0B f=0/116

i'm sure my cameras use the v4l2 protocol. So I really don't know what
is happening.

My pc has a video capture board with 8 inputs (/dev/video{0..7}) but
I'm using only three of them (/dev/video{2,3,5}).

I compiled libav as a normal user and didn't execute make install
command, because I'm testing the ffplay from the build dir.

2011/6/18 Alex Cohn <alexcohn at netvision.net.il>:
> 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
>>
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