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SpeechCodec » History » Version 3

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sylvain, 02/19/2016 10:50 PM


= Speech Codec =

The speech codec is a proprietary AMBE variant from [http://www.dvsinc.com/ DVSI]. The official spec only contain a very rough overview and no technical information about the format and how to encode or decode it.

Patents

The ETSI lists patents relevant to GMR. (See [http://ip5226084r.etsi.org/IPRDetails.aspx?IPRD_ID=151&IPRD_TYPE_ID=2&MODE=2 here]).

This list is not really complete or accurate though. In particular it's missing the patent that has the most in common with the actual codec is (US&EU versions) :

Implementation

Osmocom-GMR contains a basic implementation of a voice decoder. Its quality is not as good as the official decoder but it does produce perfectly intelligible voice. You can find the implementation in the src/codec directory of the git.

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