~singpolyma/asterisk

ref: upstream/16.2.1_dfsg asterisk/include d---------
b8ccc1fc — Alexander Traud 2 years ago
Add AMR and AMR-WB codec modules supporting transcoding

Origin: https://github.com/traud/asterisk-amr
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Last-Update: 2016-08-29

To add a codec for SIP/SDP (m=, rtmap, and ftmp), you create a format
module in Asterisk: `codec_amr.patch` (for m= and rtmap) and
`res/res_format_attr_amr.c` (for fmtp). However, this requires both
call legs to support AMR (pass-through only). If one leg does not
support AMR, the call has no audio. Or, if you use the pre-recorded
voice and music files of Asterisk, these files cannot be heard, because
they are not in AMR but in slin. Therefore, this repository adds not
just a format module for the audio-codecs AMR and AMR-WB but a
transcoding module as well: `codecs/codec_amr.c`.

This is an implementation of IETF
[RFC 4867](http://tools.ietf.org/html/rfc4867). Sometimes, AMR is
called AMR Narrowband (AMR-NB). AMR Wideband (ITU-T Recommendation
G.722.2) is sometimes abbreviated W-AMR
([GSA](http://www.gsacom.com/hdvoice/)). GSMA Mobile
[HD Voice](https://www.youtube.com/playlist?&list=PLj1MyDu3jckpSciPQ1Max0W6HDSaY8-n4)
is AMR-WB. Research papers comparing AMR and AMR-WB with other audio
codecs:
[InterSpeech 2010](http://research.nokia.com/files/public/%5B12%5D_Interspeech%202010_Voice%20Quality%20Evaluation%20of%20Recent%20Open%20Source%20Codecs.pdf),
[ICASSP 2010](http://research.nokia.com/files/public/%5B11%5D_ICASSP2010_Voice%20Quality%20Evaluation%20of%20Various%20Codecs.pdf),
[InterSpeech 2011](http://research.nokia.com/files/public/%5B16%5D_InterSpeech2011_Voice_Quality_Characterization_of_IETF_Opus_Codec.pdf).
Further
[examples…](http://www.voiceage.com/Audio-Samples-Listening-Room.html)

Gbp-Pq: Name amr.patch
130ba7ae — Bernhard Schmidt 2 years ago
Import asterisk_16.2.1~dfsg.orig.tar.xz

[dgit import orig asterisk_16.2.1~dfsg.orig.tar.xz]