On Sat, Oct 25, 2014 at 01:40:11PM +0200, wm4 wrote: > On Sat, 25 Oct 2014 13:14:26 +0200 > Reimar Döffinger <reimar.doeffin...@gmx.de> wrote: > > wm4, if you have a simple way of doing this check, please explain it. > > Otherwise I think EXTENSION score is good enough to signal "well, we > > guess that's what it is". > > There are two solutions: > - actually open the video device, and try a v4l-only ioctl() to test > whether it's really a device (the artificial separation between > avio/probing/actual opening becomes rather annoying here)
That would end up trying a v4l ioctl on each and every file that FFmpeg tries to open (unless you mean only after the /dev/video check, but that would not solve the issue you mention later). That feels a bit heavy-weight. I guess it's not unreasonable if done in addition, but on the other hand, is this likely to ever increase user experience in reality? > - add a specific protocol prefix that forces the input format, and which > lets the user invoke video capture (think MPlayer's "tv://") > > All in all, there's much you can do about raw devices. A video device > probably doesn't even need to be named /dev/video..., nor does that > filename need to be a reliable indicator that the device understand > V4L. Whatever you do, it can't be perfect, because you're working on a > too low level and system specific layer. "tv://" could solve that > actually rather elegantly, including abstracting platform differences > from the user. I admittedly just assumed that v4l2:///dev/video/... would work currently. If not, that sounds like something that can and should be fixed. However as a convenience feature, I think it is good that /dev/video just ends up picking the v4l2 input, because in almost all cases that would be the desired behaviour. It should be possible to override the other way via file:///dev/video/... I believe? If I am wrong about any of that, that would probably change my opinion. And I probably should leave this discussion to someone with a clue about this part of the code. Regards, Reimar _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel