Re: [libvidcap-devel] question about v4l2 interface

[Peter G. <jpg...@gm...>]

On Fri, Jun 20, 2008 at 8:53 PM, Rory Petty <ror...@gm...> wrote:
> Peter,
>
> Thanks for the reply. I have a camera that has an empia 2760 chip and
> is supported as a UVC device under linux using the uvcvideo kernel
> module. From what I can tell however, it only shows up as a V4L2
> device. For example, I cannot get it to show up using either
> vidcaptester or simplegrab, as it provides the error can't find device
> /dev/video0. I also tried several other utilities such as xawtv,
> tvtime and camstream and none of them can see the video device.
> However, I can see the video fine without any configuration using
> ekiga or skype. From my reading of various forums, people seem to
> indicate this is because the uvc video project is only implementing a
> v4l2 interface. Any ideas how i can get a v4l2 device to show up in a
> program like vidcaptester using only v4l? I know there is a v4l2 to
> v4l compatibility layer, but my understanding is that it does not
> implement all the mappings and that the code is getting pretty stale.

That makes sense. I suppose one way to go would be to write a v4l2
source api backend for libvidcap. In other words, write sapi_v4l2.c.
Alternatively, it seems like it would be possible to extend the
existing sapi_v4l.c to first attempt to use the v4l2 interfaces and
then fallback to v4l if there are no v4l2 devices available. Offhand,
I'm not sure which approach would be better.

I am not going to have the bandwidth to work on this myself anytime
soon (or even later), but patches are welcome.

Thanks,
Pete