On Fri, 24 Aug 2007, 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. >
Honestly, if you're trying to live-encode video into something other than MPEG2, you may be using the wrong card for the job. The PVR-xxx cards all output MPEG2 as their primary datastream. The functionality does exist to grab raw frames and audio (AFAIK), but there are limitations and I don't think Helix will like them very much (lack of an audio device, for one, and I seem to remember some trouble with audio/video sync, but it's been a while since I tried it). You may be better off using something BT8x8 or CX2388x based; that is, just a raw framegrabber that'll feed frames into the Helix encoder - and have a /dev/dspX device to record synced audio from as well. Right now I'm using Hauppauge's ImpactVCB for a similar application to yours. No tuner, but several composite and S-Video inputs and decent picture quality. BT8x8 based so it's fully Linux supported (and a real /dev/dspX audio device to record from). -- Brendan _______________________________________________ ivtv-users mailing list [email protected] http://ivtvdriver.org/mailman/listinfo/ivtv-users
