On Friday 24 August 2007 18:08:29 Erwin.D.Mascardo wrote:
> Sander Sweers wrote:
> > On vr, 2007-08-24 at 10:32 -0400, Erwin.D.Mascardo wrote:
> >> We're trying to set up a video encoding server using Debian etch
> >> and a PVR-150. The hardware that we have available does not have
> >> an onboard sound card, so ALSA is convinced that there is no sound
> >> hardware available. Is it possible to fool ALSA into thinking that
> >> /dev/video24 is a microphone or other source of audio-in?
> >
> > Not at this time. I know Hans wants /dev/video24 to change to an
> > alsa device but this is probably not high on the todo list. So for
> > now this is not possible.
> >
> > I am however a bit puzzled why you would want this to show up as a
> > microphone/other sound input. Why do you need alsa at all? Maybe
> > you can explain a bit more what the goal is and how you like it to
> > be setup. Maybe people can suggest an other or better solution to
> > the problem.
> >
> > But if you are going to use /dev/video24 then you will have live
> > with a/v being out of sync.
>
> Certainly. Our goal here is to use Helix Producer to capture video in
> .rm format, and possibly also Darwin for Quicktime videos. Producer
> uses OSS (therefore the ALSA OSS emulation) for its audio input. I
> haven't looked yet into how Darwin handles audio input, but that's a
> secondary requirement, so we'll hit it when it comes.
>
> Anyhow, Helix Producer insists on having an explicit OSS audio device
> -- if it can't find a valid /dev/dsp, it spins in a loop trying to
> find one, starting with /dev/dsp0 and continuing to increment the
> number by 1 until overflow. (Or at least I assume it will continue
> that long; I've never had the patience to wait it out, and it really
> serves no purpose to try that. Who wants to have to "warm up" an
> application in this day and age?) Hence our trying to get
> /dev/video24 recognized as a valid audio input device, even with the
> implications of a/v sync problems.
>
> The folks in the Helix community haven't had this issue come up as of
> now, and I'll be heading there next, but as I said before, I figured
> I'd try to solve the lower-level issue first, if it is indeed an
> issue.
Turning video24 into an ALSA device has been on my TODO list for ages,
but with low prio. And it is not entirely clear whether it is such a
good idea anyway having video and audio coming from completely
different drivers, especially with the A/V sync problems.
It might be a lot easier if you went with a 'normal' framegrabber card
instead of a MPEG encoder. Of course, I don't know what your
requirements are.
Regards,
Hans
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