G.729a and CM

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Feb 27th, 2001
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AV has indicated they will be supporting G.729, so, does that mean that AV will take in G.711 and compress to G.729 and decompress when you listen to it. Or does it mean that AV can take in G.729 and keep it that way upon playback? Please explain. I have read the post in regard to disk space. It just says that it is upon CPU and proceed with caution using TSP and CM.<br><br><br><br>Sean Poure<br>NEC-Voice Engineering<br>Sr. Systems Engineer<br>714 4846275<br>

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Anonymous (not verified) Tue, 02/27/2001 - 05:36
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Actually, it means all of that. We’re just SO flexible…

If you configure Unity to default to G729a we will record all messages, greetings and voice names in that format. This saves storage and bandwidth since it’s a very compressed codec. I’ll skip all the warnings about Windows not natively supporting it etc…

Also, if we have a message/prompt/greeting that happens to be stored in G711 (i.e. all our prompts are stored in this format since it sounds a lot better or messages could be in the system from before the codec was changed to G729a etc…) we will convert it on the fly to G729a. As such someone calling in on an IP phone across the WAN and cruising around in our conversation will still be getting G729a streamed to their phone even though the prompts are in G711 (MuLaw to be specific). Our CPU takes a small hit to do this conversion but that’s about it.

There one extra step here… When a call comes into a uOne port (assuming you’re using a Call Manager here) a connection type is “negotiated”. If the phone only supports G711, we have to stream that. If they support G729a, we need to stream that. As such even if we have G729a installed and enabled as our default codec, if a phone connects to us and negotiates a G711 connection type, we will convert the stream to a G711 (i.e. we’ll convert the G729a messages that user is listening to back to 711 for them).

So from Unity’s perspective, we should handle any combination of recorded formats and client streaming needs here.


Jeff Lindborg
Unity Product Architect/Answer Monkey
Cisco Systems
[email protected]
http://www.AnswerMonkey.net (new page for Unity support tools and scripts)

tpetzold_2 Mon, 03/05/2001 - 10:29
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Above and beyond the estimated 5% CPU utilization are there any delays in voice playback time or voice quality. I understand that Unity converts codecs in 8 second chunks. Does this induce any voice issues?

Thanks for all the answers and welcome to Cisco.

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