Gustavo Garcia Bernardo
2012-Apr-15 11:15 UTC
[asterisk-users] Transcoding degradation G711<->iLBC
Is it a good idea to use asterisk transcoding from G711 to iLBC or should I find out any other solution not involving transcoding (f.e. using G.729 that is supported in both sides). I'm worried about voice quality and trying to avoid paying for G.729 licensing. Anybody with experience or quantitative measurements of the voice quality degradation in that scenario? Regards, G ________________________________ Este mensaje se dirige exclusivamente a su destinatario. Puede consultar nuestra pol?tica de env?o y recepci?n de correo electr?nico en el enlace situado m?s abajo. This message is intended exclusively for its addressee. We only send and receive email on the basis of the terms set out at http://www.tid.es/ES/PAGINAS/disclaimer.aspx -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.digium.com/pipermail/asterisk-users/attachments/20120415/eb928ece/attachment.htm>
On 04/15/2012 01:15 PM, Gustavo Garcia Bernardo wrote:> Is it a good idea to use asterisk transcoding from G711 to iLBC or > should I find out any other solution not involving transcoding (f.e. > using G.729 that is supported in both sides). I'm worried about voice > quality and trying to avoid paying for G.729 licensing. > > Anybody with experience or quantitative measurements of the voice > quality degradation in that scenario?The term that may interest you is "Mean Opinion Score" and iLBC is quite good. See http://en.wikipedia.org/wiki/Mean_opinion_score Regards, Patrick
I'm quite fond of GSM610 as a low(ish) bandwidth codec - although it isn't as good as (say) speex or Silk, it is widely supported, and European users have had years of cellphone use to get used to the specific sound of a GSM call. So you can often go from a GSM610 supporting handset all the way through to a GSM supporting ITSP without needing to transcode at all. If at all possible avoid creating a path which involves 2 different lossy codecs - e.g. 729 _and_ GSM the results are significantly worse than either. If you can control all of the call path and have devices that support it, Silk is _lovely_ . It takes a bit of tuning for your expected network (which is unfortunately manual in Asterisk 10) but it is worth it. Tim. On 15 Apr 2012, at 12:15, Gustavo Garcia Bernardo wrote:> Is it a good idea to use asterisk transcoding from G711 to iLBC or should I find out any other solution not involving transcoding (f.e. using G.729 that is supported in both sides). I'm worried about voice quality and trying to avoid paying for G.729 licensing. > > Anybody with experience or quantitative measurements of the voice quality degradation in that scenario? > > Regards, > G > > Este mensaje se dirige exclusivamente a su destinatario. Puede consultar nuestra pol?tica de env?o y recepci?n de correo electr?nico en el enlace situado m?s abajo. > This message is intended exclusively for its addressee. We only send and receive email on the basis of the terms set out at > http://www.tid.es/ES/PAGINAS/disclaimer.aspx > -- > _____________________________________________________________________ > -- Bandwidth and Colocation Provided by http://www.api-digital.com -- > New to Asterisk? Join us for a live introductory webinar every Thurs: > http://www.asterisk.org/hello > > asterisk-users mailing list > To UNSUBSCRIBE or update options visit: > http://lists.digium.com/mailman/listinfo/asterisk-users-------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.digium.com/pipermail/asterisk-users/attachments/20120422/3f7f52a1/attachment.htm>