GSM 06.10 codec

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arnom
 
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Joined: Fri Nov 15, 2013 1:40 pm

GSM 06.10 codec

Post by arnom »

Hi everyone,

I'm thinking of creating an embedded client for the Free Radio Network.
However, the audio data is encoded using the GSM 06.10 standard, so I need away to decode the data and produce some sound (a portable radio will be connected to the embedded client) and I also need to encode data from a line input.
I was hoping there would be some standalone GSM codec IC's available, but I have yet to find one.
Any ideas how I can approach this problem?

Thanks,
Arno

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arnom
 
Posts: 26
Joined: Fri Nov 15, 2013 1:40 pm

Re: GSM 06.10 codec

Post by arnom »

Looks like no one has any real experience with this :(

I've also posted this question on the Arduino forum and some Dutch communities.

A summary of the suggestions I've gotten so far:
People are suggesting that I could use a DSP (never worked with that before).
Others say that the codec is pretty lightweight for today's standards and that it should be possible to run it on a microprocessor.

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arnom
 
Posts: 26
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Re: GSM 06.10 codec

Post by arnom »

So, I tried "porting" libgsm to the Arduino platform, simply by copying the necessary code into an Arduino library and adjusting the code when errors came up.
Unfortunately this does not seem to work (I didn't really think it would be that simple, but hey, it was worth a shot),
Whatever WAV49 frame I pass to the decode method, I keep getting the same bytes out of it.
My guess is that I'm hitting some limitation of the AVR somewhere (maximum integer value or something like that).

Anyway, this brings me back to square one.
Hopefully some new users read this thread and someone is willing to contribute some ideas to solve this problem.

Basically I need to accept a GSM 06.10 encoded stream of audio and convert it to something the VS1003 / VS1053 can understand and vice versa.

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