Linux Pulse or ALSA Audio sound settings for recording from Dazzle

[benawhile]

I am transferring VHS tapes to digital.

I have a working VCR, a Dazzle DVC100 and Ubuntu 22.04. I also have a CRT TV I use to monitor the VCR output.

I am in UK so the tapes are PAL - I

I was using a Windows laptop but had trouble with dropped frames, and still don't completely understand the O/P and Canvas pixel settings, so decided to migrate to the Ubuntu desktop as it is more powerful, but although the dropped frame problem seems better, I can't find the right sound settings.

In spite of Dazzle bad reputation for Audio I did get sound through on the windows laptop by using desktop audio.

However in Ubuntu I can get a sound bar displayed but the indicator isn't moving.

I have to deal with Pulse settings as well as the OBS settings and don't know where to start. Not even sure whether to use ALSA or Pulse.

Attached a few screenshots, can anyone say where I am going wrong?

For audio monitoring I intend to use the 3.5mm analogue audio output that I normally use.

 

[AaronD]

The screenshots all look good...except once you get something working, you'll want to delete or Disable all except that one. Don't leave things around that can only hurt.

...Dazzle bad reputation for Audio...

Nothing says you have to use the same device for everything. Assuming you have a picture through the Dazzle, you could use it for just that - silent as far as it knows - and use a separate standards-compliant line input for the sound.

I like the Behringer UCA202, but there are others too. You don't need anything fancy, but do make sure you know what you're getting. The UFO202 is a phono preamp that looks almost the same; you probably don't want that. It *is* switchable, but you *know* that switch is going to be in the wrong position!

 

[benawhile]

The problem is how to get one working?

 

[AaronD]

The problem is how to get one working?

A standards-compliant one, just does. A lot of things are not, and rely on the OS to fudge it into working anyway. Everything I've seen from Behringer is fully compliant, and "just works" everywhere.

 

[benawhile]

No I mean here: "once you get something working". I'm still looking into it. You say the screenshots look good but I was hoping someone could point to an incorrect setting somewhere. I am sure an audio setting must be incorrect. I was on the point of using a separate audio input for audio while going through all this in Windows but by chance found a post advising to change the source crossbar settings for the dazzle, which worked perfectly. But then found I was dropping frames.

 

[benawhile]

Update, in the end I just took the sound phono cables from the VCR direct to the computer input. Pulse dealt with the rest. Defaults were to ALSA capture device. I never found out why I couldn't get sound through the Dazzle, maybe it was a driver issue, Worked fine on Windows.

 

[AaronD]

I never found out why I couldn't get sound through the Dazzle, maybe it was a driver issue, Worked fine on Windows.

Like I said:

A lot of things are not [standards-compliant], and rely on the OS to fudge it into working anyway.

For the most part, Linux doesn't have specific drivers. Linux uses the standards. So if something follows the existing standards, then it'll work on Linux. If it doesn't, I would fault the company behind it for creating future e-waste, because that's what happens when it's no longer worth writing a custom driver for a new version of Windows or whatever, and so the perfectly-working-as-designed hardware can't be used anymore.

 

[AaronD]

I just took the sound phono cables from the VCR direct to the computer input.

Be aware that that has some special pitfalls:

• It might not actually be a stereo line input. It could be a mono mic input. Same connector, not completely compatible.
  • If you cross-connect that, you could end up with the left channel only (left is *not* mono, it's only left), while the right output of the VCR gets 5V power fed into it through a resistor and not listened to.
    • If it's a mono VCR anyway (a lot are, and I wouldn't be surprised to see the two "stereo" jacks connected on the inside), and if that works anyway, then it likely won't make much difference, but it's still not now things are supposed to work.
    • Depending on how the mic input is designed, it might not be able to turn itself down enough to avoid clipping/distortion. It's a MIC input, and mic signals are usually much weaker than what you're doing.
• If it really is an actual stereo line input, you're still not quite in the clear yet. A few are good, but it's not at all guaranteed.
  • Inside a computer is electrically noisy! It's almost entirely a digital design, with all kinds of strong, fast, sharp-edged signals running around with little concern for cross-interference because it's practically immune to that anyway. But the analog line input *is* sensitive to all that, so you get to hear what the extreme low-frequency (audible) end of all that internal chatter sounds like, in addition to what you actually meant to record.
  • Even if your particular computer happens to be relatively quiet or well-isolated, the chip itself that does that isn't exactly spectacular either. It's designed to work in that environment, and so it's just not worth making it any better than that.

So the recommendation still stands, even if you "got sound" already, to use an external device that is dedicated to capturing line-level audio. Get a chip that is actually designed to be good, outside of the noisy box.