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New Member

Compression issue. G.729 and VMO

We have unity 2.4.6-161 with callmanager 3.1.3a and ip phones 7960.

We would like to enable compression for recording so messages get smaller.

However I was told we could only use G.729 because that the only codec supported by the 7960 (beside G723).

The problem is that only VMO is capable of reading G.729. We have many users using Outlook web access to get to voicemail so this is not an option.

Is there any other way to be able to use a different codec that would be supported by apps like windows media player. We have dialogic cards if need be. I haven't be able to find a commercial version of the G729 codec that we could use with windows media player or real audio or just at least a player that would support g729.

Thanks

-Boris

7 REPLIES
Cisco Employee

Re: Compression issue. G.729 and VMO

Several folks trying to get messages to play out various hand held devices have had luck with the GSM 6.10 codec which has decent compression (much better than 711, not quite a good as 729a but it sounds better than 729a in my opinion) and is supported natively by Windows.

New Member

Re: Compression issue. G.729 and VMO

I was told by tac that I could only use a codec supported by the 7960 phone, because the unity won't handle the decompression. Is GSM 6.10 supported by the 7960?

I first wanted to use DSP group truespeech codec which is what we had before with our previous VM system using a dialogic card?

The following document talks about a codec available from cisco for windows native support

http://www.cisco.com/univercd/cc/td/doc/product/voice/c_unity/whitpapr/codecs.htm#xtocid7

is this for unity 3.1 only?

Cisco Employee

Re: Compression issue. G.729 and VMO

Unity can record messages in GSM 6.10, and when it recieves a G711 or G729 connection from an IP phone, the message will be transcoded to G711 or G729 during playback.

New Member

Re: Compression issue. G.729 and VMO

I'm confused. Tac said I could only use a codec supported by the 7960.

Does this mean either codec available on unity thru setrecordformat.exe will work fine. I thought that if you accessed your messages from a 7960 phone, unity would only send the file directly to the phone without converting it to g711 or g729 first.

I guess I could try over the week-end to flip the switch and see what happen.

-Boris

Cisco Employee

Re: Compression issue. G.729 and VMO

Yes, regardless wheather the record format is G711, G729, or GSM, Unity will transcode the message at playback to whatever the current connection is to the user.

Gold

Re: Compression issue. G.729 and VMO

Also, for the record, the 7960 can only do g.711 & g.729. The legacy Selsius phones can do g.711 & g.723.

Keith

Cisco Employee

Re: Compression issue. G.729 and VMO

Boris,

G729 is a proprietary codec licensed from Spiro Labs (my spelling may be off) and you are correct that support for G729 is not included with the standard Microsoft products. I used OWA to listen to voicemails at home through MusicMatch Jukebox v7.1, and others say that some of the Cool Edit versions offer support for G729. Maybe others on the forum might know of some other program that can support G729 as well.

Jami

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