[FFmpeg-user] ffmpeg and two (2) logitech 920 webcams

[Frank Belson]

The following is the output from ffmpeg -list_devices true -f dshow -i dummy

ffmpeg version N-87353-g183fd30 Copyright (c) 2000-2017 the FFmpeg
developers
  built with gcc 7.2.0 (GCC)
  configuration: --enable-gpl --enable-version3 --enable-cuda
--enable-cuvid --enable-d3d11va --enable-dxva2 --enable-libmfx
--enable-nvenc --enable-avisynth --enable-bzlib --enable-fontconfig
--enable-frei0r --enable-gnutls --enable-iconv --enable-libass
--enable-libbluray --enable-libbs2b --enable-libcaca --enable-libfreetype
--enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug
--enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb
--enable-libopenh264 --enable-libopenjpeg --enable-libopus --enable-librtmp
--enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtheora
--enable-libtwolame --enable-libvidstab --enable-libvo-amrwbenc
--enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp
--enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid
--enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib
  libavutil      55. 76.100 / 55. 76.100
  libavcodec     57.106.101 / 57.106.101
  libavformat    57. 82.101 / 57. 82.101
  libavdevice    57.  8.101 / 57.  8.101
  libavfilter     6.105.100 /  6.105.100
  libswscale      4.  7.103 /  4.  7.103
  libswresample   2.  8.100 /  2.  8.100
  libpostproc    54.  6.100 / 54.  6.100
[dshow @ 00000000002f6c00] DirectShow video devices (some may be both video
and audio devices)
[dshow @ 00000000002f6c00]  "Logitech Cam#1"
[dshow @ 00000000002f6c00]     Alternative name
"@device_pnp_\\?\usb#vid_046d&pid_082d&mi_00#6&10047afe&0&0000#{65e8773d-8f56-11d0-a3b9-00a0c9223196}\{bbefb6c7-2fc4-4139-bb8b-a58bba724083}"
[dshow @ 00000000002f6c00]  "Logitech Cam#2"
[dshow @ 00000000002f6c00]     Alternative name
"@device_pnp_\\?\usb#vid_046d&pid_082d&mi_00#6&3a78d907&0&0000#{65e8773d-8f56-11d0-a3b9-00a0c9223196}\global"
[dshow @ 00000000002f6c00]  "Kodak S101 Webcam"
[dshow @ 00000000002f6c00]     Alternative name
"@device_pnp_\\?\usb#vid_0979&pid_0206&mi_00#6&2455fd16&0&0000#{65e8773d-8f56-11d0-a3b9-00a0c9223196}\global"
[dshow @ 00000000002f6c00] DirectShow audio devices
[dshow @ 00000000002f6c00]  "Microphone (4- Kodak S101 Micro"
[dshow @ 00000000002f6c00]     Alternative name
"@device_cm_{33D9A762-90C8-11D0-BD43-00A0C911CE86}\Microphone (4- Kodak
S101 Micro"
[dshow @ 00000000002f6c00]  "Line (WsAudio_Device)"
[dshow @ 00000000002f6c00]     Alternative name
"@device_cm_{33D9A762-90C8-11D0-BD43-00A0C911CE86}\Line (WsAudio_Device)"
[dshow @ 00000000002f6c00]  "Microphone (2- HD Pro Webcam C9"
[dshow @ 00000000002f6c00]     Alternative name
"@device_cm_{33D9A762-90C8-11D0-BD43-00A0C911CE86}\Microphone (2- HD Pro
Webcam C9"
[dshow @ 00000000002f6c00]  "Microphone (HD Pro Webcam C920)"
[dshow @ 00000000002f6c00]     Alternative name
"@device_cm_{33D9A762-90C8-11D0-BD43-00A0C911CE86}\Microphone (HD Pro
Webcam C920)"
dummy: Immediate exit requested


On Tue, May 22, 2018 at 6:59 AM, DopeLabs <dopelabs at dubstep.fm> wrote:

> what is the output of
>
> $ ffmpeg -list_devices true -f dshow -i dummy
>
>
> if you have multiple entries of a webcam named "Logitech Cam", you can
> specify which using -video_device_number
>
> the following would select the 2nd identical device (as numbers for
> devices start at 0)
>
> $ ffmpeg -f dshow -video_device_number 1 -i video="Logitech Cam"
>
>
> im also curious.. would this work? video="Logitech Cam#0"
>
> (please include complete uncut console output)
>
> running the latest version of ffmpeg?
>
>
> > On May 19, 2018, at 3:34 17PM, Brenda Spinner <brendaspinner at gmail.com>
> wrote:
> >
> > I am using the following line to preview my webcam:
> >
> > ffmpeg -s 1280x720 -framerate 30 -pix_fmt yuv420p -rtbufsize 100MB -f
> dshow
> > -i video="Logitech Cam#1" -c:v copy -an -f sdl "WebCAM Preview"
> >
> > this line works fine with cam #1, however when try it with cam #2, I get
> > the error:
> >
> > [dshow @ 00000000002d8920] Could not set video options video=Logitech
> > Cam#2: I/O error
> >
> > Can anyone tell me why this is happening. I would like to able to preview
> > both webcams at the same time?
> >
> > Thanks, Frank
> >
> > <https://www.avast.com/sig-email?utm_medium=email&utm_
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