.VAC Audio Files / Conversion Help Needed

[derek_erdman]

Hello all: I work with a civil rights law firm and we were recently given a batch of VAC files, which are recorded prison phone calls. The file type seems to be proprietary by the company that facilitates the calls, GTL. They offer a player for the files, but we were hoping to convert them to WAV or MP3 so they could be played easily by multiple people.

I have tried to play VAC files on countless players, only their proprietary software plays them.

I have tried to convert on multiple conversion programs, nothing will recognize them.

I found a post here from 2016 that GTL offers a program to help with this, but I've called GTL and they said that they do not.

Is anybody familiar? Has anybody converted these in the past? Hoping for a holiday miracle here, thank you for even reading this.

[Cornucopia]

Part of the reason they may be proprietary may have to do with security and privacy, which bypassing can open a BIG can of worms.

But assuming you already have written approval from all involved parties (person at prison, other caller, prison/legal authorities/administration, GTL), it might be possible to do a playback-while-capture using the proprietary app and a "what you hear is what you get" audio card driver, or similarly enabled app.


Scott

[derek_erdman]

Thanks for the reply Scott. There are a massive amount of calls, we were hoping to use the audio capture route as a last resort.

And you're most likely right re: security & privacy.

[Cornucopia]

Off the top of my head, I know of NO apps that support that file format.

Although, it may be a nonproprietary format disguised as one to limit use. Check header similarities with known common formats using a hexeditor.
However, you might still be confounded in doing an extension rename - even if it is common after all - if the data stream is encrypted. Very possible.


Scott

[derek_erdman]

I tried renaming the VACs to MP3 and WAV, but neither works. Importing to Audacity as "raw audio" just produces a hiss / glitch-core sound.

So it goes.