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

Frank Belson frankbelson2 at gmail.com
Wed May 23 21:49:15 EEST 2018


DopeLabs,

   Thanks for the advice, Unfortunately, I have tried both suggestions to
no avail. No sure if i mentioned it but both webcams are the same make and
model (Logitech 920) I change the names initially as i figured two cams
with the same name was the issue. Any further suggestions would be greatly
appreciated as the current program I am using to view both camera is a CPU
hog.

Thanks, Frank

On Tue, May 22, 2018 at 12:57 PM, DopeLabs <dopelabs at dubstep.fm> wrote:

> you could try using the alternate names.. examples are shown here
>
> https://www.ffmpeg.org/ffmpeg-devices.html#dshow
>
>
> is it always that specific camera?
>
> if you connect the one that isnt working first so that its listed as #1,
> will it work?
>
> have you tried connecting the 2nd camera to a separate USB bus?
>
> you can use the following tool to get usb bus info on your system
>
> https://github.com/Microsoft/Windows-driver-samples/tree/
> master/usb/usbview
>
>
>
> > On May 22, 2018, at 9:35 03AM, Frank Belson <frankbelson2 at gmail.com>
> wrote:
> >
> > 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
> >>>
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