On 02-Jun-01 Gerd Knorr wrote: > Nemosoft Unv. wrote: >> but I was talking about what happens if the buffers >> still get full; > > Then your box is to slow for video capture. Specifying the frame rate > you want capture might help in this case[1]. For bttv this would'nt > make a big difference, but with USB hardware which might have to > post-process video data (uncompress due to the limited bus bandwidth) > this should help a bit as you avoid processing data which will be > dropped by the application anyway ... > >> drop the last or the oldest frame? > > Whichever is less work for the driver, i.e. probably drop the last one. > > Gerd > > [1] Hmm, no v4l2 ioctl for this yet. Add one? Yes please; this would be great for certain webcams. (though there are others, like the CPiA cam, who don´t have a fixed framerate at all) There is mention of an interval setting in VIDIOC_G_PARM/VIDIOC_S_PARM (which is just the reciproke of a framerate). However, I think that is a very obscure place to put it. I´d rather suggest the following: - add a flag to v4l2_capability.flags: V4L2_FLAG_VARFPS (VARiable Framerate) - either add a an ioctl (VIDIOC_S_FPS), or stick it into the v4l2_pix_format structure and other ascociated structs. - Nemosoft ----------------------------------------------------------------------------- Try SorceryNet! One of the best IRC-networks around! irc.sorcery.net:9000 URL: never IRC: nemosoft IscaBBS (bbs.isca.uiowa.edu): Nemosoft >> Never mind the daylight <<