Hi, On Wednesday 15 October 2008, [EMAIL PROTECTED] wrote: > My project is for learning only of course. I don't know nothing about > writting a linux driver, but I'm reading LDD 3rd edition. > > I want to have a list of unimplemented features in linux uvc driver, > because it may be interesting for know the possibilities of "get" this > knowledges.
The driver now supports most of the UVC specification, except - stream-based payloads - still image capture - timestamps in video streaming The first two features, especially stream-based payloads, would not be too difficult to implement, but I lack hardware for testing. I don't know of any UVC-compatible device supporting stream-based payloads or still image capture. Timestamps in video streaming is an important feature supported by all devices that is currently unimplemented. It doesn't require an in-depth knowledge of the Linux kernel of the UVC specification, but the algorithm behind the function is not trivial. Basically, 3 clocks are involved with UVC devices. The device clock (a crystal local to the device), the USB clock (shared between the device and the host) and the host clock (local to the host). With each video payload devices send two timestamps, one relative to the local device clock and one related to the USB clock. The goal is to used that information to synchronise the device clock with the host clock and produce a timestamp relative to the host that can be reported to userspace. Definitely not trivial to implement. Best regards, Laurent Pinchart _______________________________________________ Linux-uvc-devel mailing list [email protected] https://lists.berlios.de/mailman/listinfo/linux-uvc-devel
