Encode/decode AMR

I need to create custom classes for PCMtoAMR and AMRtoPCM conversion.(I don't have 开发者_开发百科any framework which I can use for this conversion)

Does anyone know of anything already done and available as open source. The language should preferably be java but it is no problem to port something from other language.

Or if you don't know please give me guidance what to read in order to implement it myself. Thanks

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This seems to be an implementation worth a look at: http://sourceforge.net/projects/opencore-amr/

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Opencore-AMR. FFmpeg uses it. you can also use FFmpeg to decode/encode, using FFmpeg's API.

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For a more in depth reading about how to decode AMR, take a look at http://wiki.multimedia.cx/index.php?title=AMR-NB

For how to use Opencore AMR to encode and decode, see http://www.codeproject.com/Articles/332109/AMR-Audio-Encoding