[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 :)


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