02-20-2009 12:43 AM - edited 03-18-2019 10:31 PM
Hi Connection does not advertise G729a - only G729 (amongst others). Is this a major overhead on Connection? Is there anything in the roadmap for G729a?
02-20-2009 06:11 AM
Hi Jag,
Good question!
There is no significant difference in overhead when using g.729. Here is a good clip that describes these relationships;
Because transcoding is inherent in every connection, there is little difference in system impact when the
line codec differs from the recording codec. The exception to this is when using the iLBC or G.722
codecs, which require more computation to transcode, and therefore have a greater system impact. The
G.722 and iLBC codecs use approximately twice the server resources that the G.711 mu-law codec uses.
Consequently, a Connection system can support only half as many G.722 or iLBC connections as it can
G.711 mu-law connections.
Supported Line Codecs (Advertised Codecs)
⢠G.711 mu-law
⢠G.711 a-law
⢠G.722
⢠G.729
⢠iLBC
Supported Recording Codecs (System-Level Recording Audio Codecs)
⢠PCM linear (default)
⢠G.711 mu-law
⢠G.711 a-law
⢠G.729a
⢠G.726
Sizing and Scaling Cisco Unity Connection
Servers
http://www.cisco.com/en/US/docs/voice_ip_comm/connection/7x/design/guide/7xcucdg025.pdf
G.729 is a high complexity algorithm, and G.729A (also known as G.729 Annex-A) is a medium complexity variant of G.729 with slightly lower voice quality. All platforms that support G.729 also support G.729A.
Understanding Codecs: Complexity, Hardware Support, MOS, and Negotiation
http://www.cisco.com/en/US/tech/tk1077/technologies_tech_note09186a00800b6710.shtml#g729
Hope this helps!
Rob
02-20-2009 07:46 AM
Hi Rob,
thanks for the reply.
We had a fault recently where we had the recording format as G729a and the advertising codec as G729 which was causing garbled messages. The only quick fix was to change the recording codec to G711 - this obviously must be less intensive than transcoding from G729 to G729a and vice versa - although G711 uses up roughly 2.5 times more disk space.
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