StereoPi records only mono audio?

S.L.P. image questions, stereoscopic video livestream and recording, stereoscopic photo capture etc.
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StereoPipi
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StereoPi records only mono audio?

Post by StereoPipi »

While experimenting with my setup, I noticed, that the enabling of audio only records mono sound. I attached a Tascam stereo recorder, which is used as a USB interface. I want my StereoPi to be stereo, in picture and sound... What do I have to do to achieve this?

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Realizator
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Re: StereoPi records only mono audio?

Post by Realizator »

Hi StereoPipi,
Well, your question is really unexpected for us! :-) We used mono mic only.

But I can suggest a solution for you.
This script is responsible for video record:

Code: Select all

opt/StereoPi/scripts/loop-record.sh
If you open it, you can find recording row:

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./bin/recorder -e udpsrc port=3003 buffer-size=200000 ! h264parse ! queue ! mux.video_0 alsasrc device=plughw:1,0 ! "audio/x-raw,channels=1,depth=16,width=16,rate=44100" ! voaacenc bitrate=128000 ! aacparse ! queue ! mux.audio_0 qtmux name=mux ! filesink location="$RECPATH/record-`date +%Y%m%d%-H%M%S`.mp4" sync=true
Here you can find audio options, in our case "audio/x-raw,channels=1,depth=16,width=16,rate=44100"

So you can set 2 channels for your setup, and this should work.
I have no stereo microphone to check this out, and I will be pleased if you can test this stereo sound mode.
Eugene a.k.a. Realizator

StereoPipi
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Location: Germany

Re: StereoPi records only mono audio?

Post by StereoPipi »

Realizator thank you for you answer. I tried it, but with a funny success :o I get recordings, but most of them I can not view (viewer does not even start).
Those who can be watched, have mono audio. :?:
...still searching for clues... :D

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Realizator
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Re: StereoPi records only mono audio?

Post by Realizator »

StereoPipi, as I mentioned we have no such experience with stereoscopic sound. But if I will face such a problem, at first I try to look at input devices names recognized by the system. May be installed drivers does not support stereoscopic sound or other issues.

As we used pulseadio, you may look at the devices list like this:

Code: Select all

pactl list
To filter out this result you may use some tips from this article.
Eugene a.k.a. Realizator

AaronD123
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Re: StereoPi records only mono audio?

Post by AaronD123 »

This is an old thread now (just over 2 years), but I don't see a resolution. Like the OP, I also have a project idea that requires 3D video with stereo audio.

So far in this thread, I see that it didn't work at the time of writing, a little bit of troubleshooting, and nothing more. No results from the last bit of troubleshooting, and nothing to say that it works now.

If you still need something to test with, this is a cheap and USB-standards-compliant stereo line-in:
https://www.behringer.com/product.html?modelCode=P0484
My Linux systems pick that right up and run with it, including a RasPi for one of them, running the standard Raspbian / Raspberry Pi OS.

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Re: StereoPi records only mono audio?

Post by Realizator »

AaronD123 thank you for your link!
Actually a lot of users work with the stereo audio recordings using advanced external audio cards. I know a few projects who did this in their solutions based on the StereoPi :)
Eugene a.k.a. Realizator

AaronD123
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Re: StereoPi records only mono audio?

Post by AaronD123 »

So does that mean a stereo soundtrack to a 3D video "just works" now? That'd be good to know, since a Google search gave me this thread that (so far) says it doesn't.

---

And in the time since I posted that, I got to thinking that I might want a 4- or even 6-channel audio recording, as 2 or 3 different taps from an external DSP that mixes two different stereo sources and does some processing along the way. I'll decide in post, whether to a) re-mix the two independent raw sources, taken from those tracks of the video, or b) take the live-finished output as-is, taken from the other tracks of the same video. As far as the StereoPi is concerned though, it's just a many-channel line input.

So, can StereoPi capture multitrack (manytrack?) audio alongside a 3D video, keep them separate (not mix them down to stereo or mono), and have that "just work" provided that ALSA / PulseAudio is okay with it?

(At one point, I had an 18in/18out USB soundcard from the same brand, and my Pi was happy with that too, at least enough for `arecord` to dump those 18 tracks to a file for 3 hours without a glitch, for re-mixing later. So I know that that side is possible. I doubt I'll use that many audio tracks under a 3D video though!)

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