[FFmpeg-user] dshow questions

Michael Koch astroelectronic at t-online.de
Sat Aug 8 12:23:28 EEST 2020 

Hi,

I have two questions about the dshow input device.

Question 1:
On the wiki page https://trac.ffmpeg.org/wiki/DirectShow can be found 
this example:

ffmpeg -f dshow -video_size 1280x720 -framerate 15 -vcodec mjpeg -i 
video="Integrated Camera" out.avi

Is -vcodec in this case an undocumented option of the dshow input 
device? I ask because it's written before -i.
Or is it an option for the output, and could (or should?) be written 
before the output file?


Question 2:
I have this HDMI to USB converter (which is working very good, by the way):
https://www.ebay.de/itm/1080P-HDMI-Videoaufnahme-Video-Capture-Card-Grabber-USB2-0-Recorder-Adapter/293641909414

When I list the options with this command line

ffmpeg -list_options 1 -f dshow -i video="USB Video"

this is the output:

C:\Users\mKoch\Desktop>c:\ffmpeg\ffmpeg -list_options 1 -f dshow -i 
video="USB V
ideo"
ffmpeg version git-2020-08-02-b48397e Copyright (c) 2000-2020 the FFmpeg 
develop
ers
   built with gcc 10.2.1 (GCC) 20200726
   configuration: --enable-gpl --enable-version3 --enable-sdl2 
--enable-fontconfi
g --enable-gnutls --enable-iconv --enable-libass --enable-libdav1d 
--enable-libb
luray --enable-libfreetype --enable-libmp3lame 
--enable-libopencore-amrnb --enab
le-libopencore-amrwb --enable-libopenjpeg --enable-libopus 
--enable-libshine --e
nable-libsnappy --enable-libsoxr --enable-libsrt --enable-libtheora 
--enable-lib
twolame --enable-libvpx --enable-libwavpack --enable-libwebp 
--enable-libx264 --
enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma 
--enable-zlib --e
nable-gmp --enable-libvidstab --enable-libvmaf --enable-libvorbis 
--enable-libvo
-amrwbenc --enable-libmysofa --enable-libspeex --enable-libxvid 
--enable-libaom
--enable-libgsm --enable-librav1e --disable-w32threads --enable-libmfx 
--enable-
ffnvcodec --enable-cuda-llvm --enable-cuvid --enable-d3d11va 
--enable-nvenc --en
able-nvdec --enable-dxva2 --enable-avisynth --enable-libopenmpt --enable-amf
   libavutil      56. 57.100 / 56. 57.100
   libavcodec     58. 99.100 / 58. 99.100
   libavformat    58. 49.100 / 58. 49.100
   libavdevice    58. 11.101 / 58. 11.101
   libavfilter     7. 87.100 /  7. 87.100
   libswscale      5.  8.100 /  5.  8.100
   libswresample   3.  8.100 /  3.  8.100
   libpostproc    55.  8.100 / 55.  8.100
[dshow @ 0000000000374800] DirectShow video device options (from video 
devices)
[dshow @ 0000000000374800]  Pin "Capture" (alternative pin name "0")
[dshow @ 0000000000374800]   vcodec=mjpeg  min s=1920x1080 fps=5 max 
s=1920x1080
  fps=30
[dshow @ 0000000000374800]   vcodec=mjpeg  min s=1920x1080 fps=5 max 
s=1920x1080
  fps=30
[dshow @ 0000000000374800]   vcodec=mjpeg  min s=1600x1200 fps=5 max 
s=1600x1200
  fps=30
[dshow @ 0000000000374800]   vcodec=mjpeg  min s=1600x1200 fps=5 max 
s=1600x1200
  fps=30
[dshow @ 0000000000374800]   vcodec=mjpeg  min s=1360x768 fps=5 max 
s=1360x768 f
ps=30
[dshow @ 0000000000374800]   vcodec=mjpeg  min s=1360x768 fps=5 max 
s=1360x768 f
ps=30
[dshow @ 0000000000374800]   vcodec=mjpeg  min s=1280x1024 fps=5 max 
s=1280x1024
  fps=30
[dshow @ 0000000000374800]   vcodec=mjpeg  min s=1280x1024 fps=5 max 
s=1280x1024
  fps=30
[dshow @ 0000000000374800]   vcodec=mjpeg  min s=1280x960 fps=5 max 
s=1280x960 f
ps=50
[dshow @ 0000000000374800]   vcodec=mjpeg  min s=1280x960 fps=5 max 
s=1280x960 f
ps=50
[dshow @ 0000000000374800]   vcodec=mjpeg  min s=1280x720 fps=10 max 
s=1280x720
fps=60.0002
[dshow @ 0000000000374800]   vcodec=mjpeg  min s=1280x720 fps=10 max 
s=1280x720
fps=60.0002
[dshow @ 0000000000374800]   vcodec=mjpeg  min s=1024x768 fps=10 max 
s=1024x768
fps=60.0002
[dshow @ 0000000000374800]   vcodec=mjpeg  min s=1024x768 fps=10 max 
s=1024x768
fps=60.0002
[dshow @ 0000000000374800]   vcodec=mjpeg  min s=800x600 fps=10 max 
s=800x600 fp
s=60.0002
[dshow @ 0000000000374800]   vcodec=mjpeg  min s=800x600 fps=10 max 
s=800x600 fp
s=60.0002
[dshow @ 0000000000374800]   vcodec=mjpeg  min s=720x576 fps=10 max 
s=720x576 fp
s=60.0002
[dshow @ 0000000000374800]   vcodec=mjpeg  min s=720x576 fps=10 max 
s=720x576 fp
s=60.0002
[dshow @ 0000000000374800]   vcodec=mjpeg  min s=720x480 fps=10 max 
s=720x480 fp
s=60.0002
[dshow @ 0000000000374800]   vcodec=mjpeg  min s=720x480 fps=10 max 
s=720x480 fp
s=60.0002
[dshow @ 0000000000374800]   vcodec=mjpeg  min s=640x480 fps=10 max 
s=640x480 fp
s=60.0002
[dshow @ 0000000000374800]   vcodec=mjpeg  min s=640x480 fps=10 max 
s=640x480 fp
s=60.0002
[dshow @ 0000000000374800]   pixel_format=yuyv422  min s=1280x720 fps=10 
max s=1
280x720 fps=10
[dshow @ 0000000000374800]   pixel_format=yuyv422  min s=1280x720 fps=10 
max s=1
280x720 fps=10
[dshow @ 0000000000374800]   pixel_format=yuyv422  min s=1920x1080 fps=5 
max s=1
920x1080 fps=5
[dshow @ 0000000000374800]   pixel_format=yuyv422  min s=1920x1080 fps=5 
max s=1
920x1080 fps=5
[dshow @ 0000000000374800]   pixel_format=yuyv422  min s=1600x1200 fps=5 
max s=1
600x1200 fps=5
[dshow @ 0000000000374800]   pixel_format=yuyv422  min s=1600x1200 fps=5 
max s=1
600x1200 fps=5
[dshow @ 0000000000374800]   pixel_format=yuyv422  min s=1360x768 fps=8 
max s=13
60x768 fps=8
[dshow @ 0000000000374800]   pixel_format=yuyv422  min s=1360x768 fps=8 
max s=13
60x768 fps=8
[dshow @ 0000000000374800]   pixel_format=yuyv422  min s=1280x1024 fps=8 
max s=1
280x1024 fps=8
[dshow @ 0000000000374800]   pixel_format=yuyv422  min s=1280x1024 fps=8 
max s=1
280x1024 fps=8
[dshow @ 0000000000374800]   pixel_format=yuyv422  min s=1280x960 fps=8 
max s=12
80x960 fps=8
[dshow @ 0000000000374800]   pixel_format=yuyv422  min s=1280x960 fps=8 
max s=12
80x960 fps=8
[dshow @ 0000000000374800]   pixel_format=yuyv422  min s=1024x768 fps=10 
max s=1
024x768 fps=10
[dshow @ 0000000000374800]   pixel_format=yuyv422  min s=1024x768 fps=10 
max s=1
024x768 fps=10
[dshow @ 0000000000374800]   pixel_format=yuyv422  min s=800x600 fps=5 
max s=800
x600 fps=20
[dshow @ 0000000000374800]   pixel_format=yuyv422  min s=800x600 fps=5 
max s=800
x600 fps=20
[dshow @ 0000000000374800]   pixel_format=yuyv422  min s=720x576 fps=5 
max s=720
x576 fps=25
[dshow @ 0000000000374800]   pixel_format=yuyv422  min s=720x576 fps=5 
max s=720
x576 fps=25
[dshow @ 0000000000374800]   pixel_format=yuyv422  min s=720x480 fps=5 
max s=720
x480 fps=30
[dshow @ 0000000000374800]   pixel_format=yuyv422  min s=720x480 fps=5 
max s=720
x480 fps=30
[dshow @ 0000000000374800]   pixel_format=yuyv422  min s=640x480 fps=5 
max s=640
x480 fps=30
[dshow @ 0000000000374800]   pixel_format=yuyv422  min s=640x480 fps=5 
max s=640
x480 fps=30
video=USB Video: Immediate exit requested

Why is each line listed twice? Might there be a difference between the 
lines, but FFmpeg can't show what the difference is?

Thanks,
Michael

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