On Sat 13 Mar 2021 at 00:09:29 (+0100), deloptes wrote: > Susmita/Rajib wrote: > > > > Expectation is enabling Duplex audio. Record while playing AV stream. > > With pulseaudio Volume Control. Isn't possible presently. > > I am not sure what you mean - the use case "Record while playing AV stream" > seems trivial.
I (≠ OP) don't use pulseaudio as a matter of course. It's meant to give benefits, but can add undesired complexity. So I generally stick with ALSA. The downside, though, is that although alsamixer may show that there's a Capture device (slider) in the Capture (F4) window, it will only record sounds from the Microphone, and not from, say, the browser. Most of the time, this doesn't matter, as I have developed several techniques over the years for capturing Transport Stream files from the cache, and assembling them into seamless live video, and even slurping files out of the browser's /proc/<PID>/fd thingies when youtube_dl fails to download a video. But nowadays, there are some audio links that play quite happily without leaving any trace that I can find. Which leaves only the option of recording the soundcard output. Some computers have both LineOut and LineIn, and these can be connected together, but that's not a very good solution in terms of noise. My latest acquisition, a Dell Precision T3500, fell into my lap just as my old Pentium III (Yamaha ymf740c) expired, and has the similar ability to record from the browser (I suppose that's the PCM). It's as tedious as recording from, say, vinyl, as you have to top, tail, and possibly split all the recordings you make. There's also the business of setting levels, and so on; all unnecessary operations if only you could grab the digital output. But it's the best I can manage. Fortunately I haven't met this problem with videos that I want, only audio recordings. Any idea what technologies are being used by these websites? I don't want to give examples as I'm not sure they condone recording their output, and some of the credentials I use are decidedly ancient and technically should have been expired. (I think of myself as a visiting alumnus.) > You should describe what you are doing. I doubt PA has to do something with > that. I've read that PA is supposed to be able to make connections in software that aren't offered by the hardware, rather like JACK is also meant to do. I'm guessing that might be the OP's interest. > What applications and how are they accessing your audio device. In my case, that's FF. I sometimes read here that FF needs PA to produce sound from webpages, but I've never found that to be so. I do usually have to fiddle with magic spells to share ALSA (with ~/.alsa-configs/asound.conf), allowing two users' browsers (FF), and their own mpv programs, all to play videos simultaneously on one Xserver. (IOW an almighty cacophony.) I hope my use case is close enough to the OP's to be a useful sidebar. Cheers, David.
