On Fri, 2002-04-19 at 09:57, Munaut Sylvain wrote: > I've a webcam based on the NW812 chip which is not supported under > linux. And i'd like to write a driver for it. But the firm that sell > this chip don't want to release technical spec about this chip ... So > I'd like to "guess" it's protocol ...
Just make sure this is NEW chipset. It could be a rehash of an old one, already known and with a driver available. > My first question is : Are all usb webcam using about the same protocol > ( i mean is there a lot of similarities between protocols or are they > all completel different ? ) Completely different. > And the second one : I suppose some people have already done this ( > guessing protocols ). Do you have some tip on how to do ? > I use a USB spy program under win32 to listen to the USB port while i'm > using the web cam. Do you knwo better spy program than "usb snoop" ? This should be good enough. Webcams send lots of data, so you may need to modify the sniffer to discard some packets that you have no use for, because Win32 kernel debugger buffer is of limited size and performance. You may also need to write some Perl code to parse the captured data, if you need that. You may need to also write some code to try the decoder. When you know how to control the chipset, consider writing a minidriver to use usbvideo module for all the v4l stuff. You will save yourself a lot of trouble, and won't need to do v4l1 -> v4l2 migration later. Dmitri
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