Hi Harri, On Monday 25 June 2007, Harri Klapuri wrote: > Hi Laurent, > > >> I know. Actually the problem is the same for stream-based because > >> the GUID is needed there, too. > > > > You're right, but MPEG should still not be a frame-based format :-) > > Usually MPEG formats are transmitted as streams but encoders > and decoders often work on full frames. Forcing the frames > into a byte-oriented stream seems like a loss of information.
Isn't that information embedded in the MPEG stream anyway ? > Isn't V4L2 inherently frame-oriented or is there a way to > pass streams/packets, too? A stream contains frame indicators > of course, so the driver could be looking for them but that > means more work for the driver. V4L2 is buffer oriented. If I'm not mistaken, a buffer is not required to be filled with a complete video frame. The driver will return MPEG video data to userspace without bothering to check frame boundaries. > > Has MS defined GUIDs for the different MPEG payloads ? > > I am not aware of anything useful in this area. :-( > >> It is not out yet (available for sale). Besides the typical MJPEG > >> and Uncompressed, it supports frame-based payloads. > > > > Will it support MPEG as well ? > > It is possible. In any case I anticipate the number of > MPEG4 devices is going to increase pretty soon. I agree with you there. However, I'd rather wait for the first devices to hit the market before adding frame-based MPEG support. As stated before, MPEG should be stream-based, so I hope no devices will return MPEG data in a frame-based format. I committed frame-based formats support but removed MPEG support for now. Let's discuss the MPEG issue when real-life examples will be available. Cheers, Laurent Pinchart _______________________________________________ Linux-uvc-devel mailing list [email protected] https://lists.berlios.de/mailman/listinfo/linux-uvc-devel
