[Cin] offtopic: Digitize and record Video with A/D USB adapters
Stefan de Konink
stefan at konink.de
Tue Sep 28 12:55:31 CEST 2021
On Tuesday, September 28, 2021 12:47:17 PM CEST, mnieuw--- via Cin wrote:
> - I would avoid plug-in cards, you are completely dependent on the
> manufacturer's support for Linux drivers. On the other hand, USB
> grabbers usually follow standard USB audio/video rules, and almost
> always work.
Your argument is valid for drivers in Linux. The problem with the USB
drivers and Linux;
- Linux supports a single endpoint per device, when the device needs two
independent drivers this causes a problem. For example V4L + libusb with
an ATEM.
> - You want grabbing in uncompressed 4:2:2 format (4:4:4 does not make
> much sense for PAL), the datastream is no problem for even USB2 .
- The bus speed can be saturated
- ISO transport is notoriously bad
I own a very great audio device (YellowTec Puc2) works very well, but I
would not connect it to a system with a shared USB bus.
> - CinGG did not work with my then Easycap grabber, because it could not
> switch it to PAL, and the default after plugging it in was NTSC.
> However, this was a bug in CinGG, VLC worked fine with the same
> device. I did some work on it but never finished it, lack of time.
v4l2-ctl to the rescue :)
--
Stefan
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