Subject: [AVT] G.729 -> G.711 conversion

From: "FOREST Laurent - MTR ( [email-masked] )" <[email-masked]>
Date: Fri, 13 Sep 2002 17:47:37 +0200

Hello,

For an application, I need a CODEC translation between G.729 and G.711.

Could someone tell me what the are main difficulties of this translation
(performance impact, tough implementation, etc.)?
Can this kind of translation be done in a piece of software running on a
server or should it be done imperatively in a DSP?

Is there any freeware that performs this kind of translation?

Thank you
Laurent
_______________________________________________
Audio/Video Transport Working Group
[email-masked]
https://www1.ietf.org/mailman/listinfo/avt

---

From: [email-masked]
Date: Mon, 16 Sep 2002 08:16:37 +0200

Dear Laurent

The format in and out of G.729 is linear PCM; to convert to/from you may use
many tools available for G.711 compression & expansion (aka companding). One
of them is the ITU-T Software Tool Library (STL2000), which is defined in
ITU-T Rec. G.191. In addition, the STL2000 contains valided implementations
of several codecs, eg RPE-LTP, G.726, G.727, G.722 and other tools as
telecom filtering module, error insertion, MNRU, speech voltmeter, and a few
odd utilities.

To get hold of it, please visit
 
<http://www.itu.int/rec/recommendation.asp?type=folders&lang=e&parent=T-REC-
G.191>
http://www.itu.int/rec/recommendation.asp?type=folders&lang=e&parent=T-REC-G
.191

You may find useful that it is possible, under certain conditions, to
download ITU-T Recommendations for free; see the following page for details:
 <http://www.itu.int/publications/bookshop/how-to-buy.html#free>
http://www.itu.int/publications/bookshop/how-to-buy.html#free

In terms of quality impact, G.711 will add some grainness to the decoded
signal (since modulated gaussian-type noise is added by the companding
process). However, the quality should not be affected for a one-hop (ie one
transcoding) process.

In the hope the information is useful -- best regards,
Simao Campos-Neto

> -----Original Message-----
> From: FOREST Laurent - MTR ( [email-masked] )
> [  <mailto:[email-masked]> mailto:[email-masked]]
> Sent: 13 September 2002 17:48
> To: [email-masked]
> Subject: [AVT] G.729 -> G.711 conversion
>
>
> Hello,
>
>  <https://www1.ietf.org/mailman/listinfo/avt>