On Fri, Jan 22, 2010 at 8:42 PM, Hans Verkuil <hverkuil@xxxxxxxxx> wrote: > On Friday 22 January 2010 04:00:53 Andy Walls wrote: >> On Fri, 2010-01-22 at 10:42 +0800, Michael Qiu wrote: >> > Hi all, >> > >> > How can I export my MPEG decoder control interface to user space? >> > Or in other words, which device file(/dev/xxx) should a proper >> > driver for mpeg decoder provide? >> >> The MPEG decoder on a PVR-350 PCI card provides a /dev/video interface >> (normally /dev/video16). >> >> The interface specification to userspace is the V4L2 API: >> >> http://www.linuxtv.org/downloads/video4linux/API/V4L2_API/spec-single/v4l2.html > > Not really. The v4l2 API specifies the MPEG encoder part, but not the decode > part. > > The decoder part is (unfortunately) part of the DVB API. > > Some ioctls are documented here: > > http://www.linuxtv.org/downloads/v4l-dvb-apis/ch11s02.html > > However, that documentation is very out of date and you are better off looking > in the include/linux/dvb/video.h header. > > In particular the new struct video_command and associated ioctls provides > you with more control than the older VIDEO_CMD_ ioctls. > > Note that the V4L2 API will get a new event API soon that should supercede the > event implementation in this video.h. The video.h implementation is pretty > crappy (most of what is in there is crappy: poorly designed without much thought > for extendability). > >> > And, in linux dvb documents, all the frontend interface looks like >> > /dev/dvb/adapter/xxx, it looks just for PCI based tv card. >> > If it's not a TV card, but a frontend for a embedded system without >> > PCI, which interface should I use? > > V4L2, but with the ioctls defined in dvb/video.h. See for example the ivtv > driver (ivtv-ioctl.c). For a DVB STB, you don't need to use V4L2 in anyway.. It doesn't make sense either... The presentation/scaler used with V4L2 is pretty much legacy code. For STB's generally DirectFB is used to give full control. Regards, Manu -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
