Odd/Challenging Audio Question

[davidgriswold]

This is not the normal question that gets asked here. I hope someone has some idea of what I can do or where I can go for help.

I have some files that are a concatenation of what appears to be raw PCM data with a proprietary delimiter. If I strip the PCM data out and save to a separate file, I can load it in GoldWave as a PCM, 8 bit, Mono, 4000 Hz file and play it. I suspect that there may be more to the encoding, because, although I can understand it, it is very distorted. This part is the problem.

This file is from a proprietary IVR (Integrated Voice Response) telephone system and I hope to be able to salvage the content of these files instead of having to get them rerecorded.

If anyone has any ideas, knows of a utility that may help me massage the files or knows of another forum where audio professionals hang out, I would greatly appreciate it. I would gladly forward a sample of the audio to anyone that would like to take a look at it.

Thanks,
David

[BJ_M]

IVR's ussually use ITU standard G.729 voice compression on the RAW data . though i don't really know how to decompress it without the hard ware it was made on or at least a software codec perhaps to de-compress it totally .....

you can buy this codec here: http://shop.store.yahoo.com/asteriskpbx/asteriskg729.html


but if you search around you may be able to find it posted somewhere ...

pocket pc's all use this codec (also) and MSDN has a lot of info about as well ..

what you have may use a different compression for all i know ..... in that case -- you may have to open the file possably in a hex editor and see if you can find a clue about its origins and compresion type ...


ussually anyway you would import such unknown files as "raw" into goldwave or soundforge ..

[davidgriswold]

Thanks for the info. Soundforge has a tool in it (Vinyl Restoration) that makes the soundwave at least look normal. It still sounds like crap, but it is only a 4k Hz sample, so I guess it shouldn't sound great anyway.

If anyone else has any more input, I am still open to suggestions.

Thanks again,
David