On 18 Oct 2001, Gerd Knorr wrote: > > > v4l2 has buffer flags for even/odd field, v4l has not. Is there any way > > > > Does it make sense to do v4l2 ? When is it going to make it into the > > kernel ? (I don't want to require people to patch the kernel in addition > > to everything else..) > > including v4l2 is planned for 2.5.x. And 2.6.x is still a ways off. What do you think about having "extended v4l" ? Specifically, I was thinking of adding an extra offset field to mmap ioctls that would point not to a frame but to a control struct that would contain fields like timestamp, frame phase (even, odd or something else), and whatever else is needed. This way read/write operation will be unchanged, but applications that use mmap can take advantage of extra features. best Vladimir Dergachev > > > > to capture both fields interleaved into one buffer? Using pitch = > > > 2*scanlinelength or something like that? Applications expect the image > > > interleaved in one buffer ... > > > > Not really. (As DMA granularity is 4096 bytes, but pitch is 640*2). I > > could make it fake this during read but this requires doubling buffers. > > (4 instead of 2, 1.2meg ram instead of 600k) > > Hmm, bad. > > > > Any v4l app should work (in theory ...). > > > There is no test suite (at least I don't know any ...). > > > > Well, I just wanted to take the easy way and get this to work with some > > existing apps instead of implementing ioctl's one by one ;) > > As you already have xawtv you can try this one ... > > > > Using more (than two) capture buffers basically reduces the risc that > > > you lose frames on temporary CPU load peaks. > > > > Do you know of any apps that actually care about latency issues ? > > Videoconferencing is very sensible to latencies, you might have a loom > at www.openh323.org / gnomemeeting. > > Gerd > > > > _______________________________________________ > Video4linux-list mailing list > Video4linux-list@xxxxxxxxxx > https://listman.redhat.com/mailman/listinfo/video4linux-list >