[Libav-user] OV518

[Andrew Randrianasulu]

В сообщении от Monday 27 April 2020 16:25:36 - - написал(а):
>  Hello, 

>  
>  I would like to use an old webcam for webrtc with firefox. My Firefox (86.6.0esr, latest on CentOS 7) aborts before playing the webcam. As far as I know, firefox uses ffmpeg for video playback. So I kindly ask this mailing list for some advice. 
>  
>  I can play the webcam (TerraCAM USB Pro) with "vlc v4l2:///dev/video0", but 
>  
>  "ffmpeg -f v4l2 -i /dev/video0" throws : 
>  ... 
>  
>  [video4linux2,v4l2 @ 0xcb3a500] Cannot find a proper format for codec 'none' (id 0), pixel format 'none' (id -1) 
> Assertion *codec_id != AV_CODEC_ID_NONE failed at src/libavdevice/v4l2.c:815 
>  
>  "v4l2-ctl --list-formats-ext" shows Omnivision chipset OV518 with special compression format : 
>  
>  ioctl: VIDIOC_ENUM_FMT 
> Index : 0 
> Type : Video Capture 
> Pixel Format: 'O518' (compressed) 
> Name : GSPCA OV518 
> Size: Discrete 320x240 
> Size: Discrete 640x480 
> 
>  
>  "ffmpeg -f -v4l2 -list_formats all -i /dev/video0" shows, that this format is not supported : 
>  
> 
>  
>  ffmpeg version 4.2.2-static https://johnvansickle.com/ffmpeg/ Copyright (c) 2000-2019 the FFmpeg developers 
> built with gcc 8 (Debian 8.3.0-6) 
> configuration: --enable-gpl --enable-version3 --enable-static --disable-debug --disable-ffplay --disable-indev=sndio --disable-outdev=sndio --cc=gcc --enable-fontconfig --enable-frei0r --enable-gnutls --enable-gmp --enable-libgme --enable-gray --enable-libfribidi --enable-libass --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librubberband --enable-libsoxr --enable-libspeex --enable-libsrt --enable-libvorbis --enable-libopus --enable-libtheora --enable-libvidstab --enable-libvo-amrwbenc --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzimg 
> libavutil 56. 31.100 / 56. 31.100 
> libavcodec 58. 54.100 / 58. 54.100 
> libavformat 58. 29.100 / 58. 29.100 
> libavdevice 58. 8.100 / 58. 8.100 
> libavfilter 7. 57.100 / 7. 57.100 
> libswscale 5. 5.100 / 5. 5.100 
> libswresample 3. 5.100 / 3. 5.100 
> libpostproc 55. 5.100 / 55. 5.100 
> [video4linux2,v4l2 @ 0xc482600] Compressed: Unsupported : GSPCA OV518 : 320x240 640x480 
> /dev/video0: Immediate exit requested 
> 
>  
>  As you see, I am using latest ffmpeg static build. I also tried an own build, but so far without success. 
>  
> 
>  
>  So, how can I get this webcam running (hopefully for firefox, too)? 

may be try to LD_PRELOAD v4l2 library, like desribed here?

https://wiki.archlinux.org/index.php/Webcam_setup

If the application has V4L2 support but no pixelformat support then use the following command: 
LD_PRELOAD=/usr/lib/libv4l/v4l2convert.so application


>