about 3gp & GSM_AMR audio code

[erspicu]

is there any tool(or encoder) for coding GSM_AMR audio code ?

Some mobile device play *.3gp file with GSM_AMR audio.

I can use MP4BOX for creating *.3gp file but I can't make a GSM_AMR audio.

[guada 2]

RN Helix Mobile Producer Professional.v11.0.547.

Bye ;)