On Sat, 2003-12-20 at 01:06, Marcus Metzler wrote: > > I'd like to add this patch to dvb-kernel's linux/dvb/video.h, so > > userspace programs can adjust video system settings (PAL/NTSC) depending > > on the frame rate and video size. I think it won't break binary > > compatibility. The frame rate values are taken from ITU-T Rec. H.262 > > (2000 E) Table 6-4. May I proceed? > > > > Where is this relevant and wouldn't it make more sense in a > video4linux(1/2) device? > It makes no sense for playback, because you know what you are > playing. For a demux as source, you can handle it inside the > driver. Any information needed for the display should then be handled > by the display device, i.e. a v4l device. While I agree with you that we both know what kind of stream we are playing, John Doe doesn't. He knows the play and stop buttons and can hopefully tell whether his TV supports NTSC and/or PAL. Then, we have this VIDEO_SET_SYSTEM ioctl which doesn't make much sense unless the driver is able to tell some details about the current stream. It is also nice to have these details displayed on the user interface. If the mpeg decoder driver switches to NTSC without notifying userspace, then it is not possible to configure the DENC or the Framebuffer accordingly. Also I don't see the need to create a v4l2 device just for obtaining the frame rate of a stream. Until now you can create quite good DVB applications pretty much without knowing that v4l exists at all. Regards, Andreas
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