[Cin] offtopic: HDMI capture
Andrew Randrianasulu
randrianasulu at gmail.com
Tue Nov 17 00:41:38 CET 2020
I did little research , and apparently there are some HDMI capture cards/USB 3.0 dongles.
But Magewell XI100DUSB-HDMI tend to cost $300 (!!) and while it was reported to work with Linux and standard (in-kernel) UVC driver it only supported 4:2:2
8-bit per component capture ....
[video4linux2,v4l2 @ 0x1e46dc0] The v4l2 frame is 0 bytes, but 4147200 bytes are expected. Flags: 0x00002045
Input #0, video4linux2,v4l2, from '/dev/video0':
Duration: N/A, bitrate: 995328 kb/s
Stream #0:0: Video: rawvideo (YUY2 / 0x32595559), yuyv422, 1920x1080, 995328 kb/s, 30 fps, 30 tbr, 1000k tbn, 1000k tbc
https://trac.ffmpeg.org/ticket/4030
(this bug was fixed, just showing where I get my info)
Unfortunately, there apparently was some another bug in Linux kernel:
https://lore.kernel.org/linux-usb/20180515112251.51392d42%40litschi.hi.pengutronix.de/T/
Not enough bandwidth with Magewell XI100DUSB-HDMI
2018-01-19 20:12
Not sure if it was fixed or not.
Declink cards require their own SDK (non-free)
On windows it seems to be working ... with some effort:
https://ianmorrish.wordpress.com/2019/04/02/ffmpeg-with-decklink-support-for-windows/
there was ffmpeg page showing directshow capture on Windows, this lists some 10-bit formats like
[dshow @ 0000007201cda8a0] vcodec=v210 min s=3840x2160 fps=30 max s=3840x2160 fps=30
[dshow @ 0000007201cda8a0] vcodec=r210 min s=1920x1080 fps=23.976 max s=1920x1080 fps=23.976
https://wiki.multimedia.cx/index.php/R210
This codec is used in TV & film production and stores raw 10-bit RGB data. Each red, green, and blue color component is 10 bits wide.
https://wiki.multimedia.cx/index.php/V210
The v210 format is a packed YUV 4:2:2 format with 10 bits per component.
https://trac.ffmpeg.org/wiki/Capture/Blackmagic
But you probably need real ultrafast (NVME?) drive for working with those .... at least at higher resolutions.
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