G729 versus Speex comparison


#1

Does anyone have experience with both of these?
How do they compare? Do many hardware ATS support Speex ?
I am ok with using Xlite for now.

Thanks for the info.


#2

speex.org/comparison.html


#3

Well yes I saw that, but I wanted actual opinions from users.

However what do most people use? I would suppose it is not speex as it is not supported by hardware, but it would come in handy for call centers as a codec would not need to be paid for for the call stations.

I don’t know enough about * yet, but do many people enable it as the default codec for * to * communications?

KM


#4

As you have stated, the issue with Speex is that many devices and providers do not support it, therefore the load on your Asterisk increases due to the need for transcoding if you decide to use it. I would say that the most used in the world of Asterisk are G711, G729 and gsm (ie - the standard sound files for Asterisk are gsm based).

Experiences with codecs are largely subjective and highly dependent on how the system and network is configured/architectected. I would say give them a try and see what works best for you.

Remember, there is always a trade-off between server load (transcoding) and network savings (bit rates), the more ‘pass-through’ of codecs you may do the better your Asterisk implementation will scale.


#5

CPU load isn’t an issue, however how much delay is introduced?

I would think that if you run your own server you could make multiple accounts and that then connect to your server using the same codec as the carrier you wish to use.

Account1Codec1>SERVER>ServiceCodec1
Account2Codec2>SERVER>ServiceCodec2

versus

ServiceCodec1>SERVER>ServiceCodec1
ServiceCodec1>SERVERTRANSCODE>ServiceCodec2

Am I correct? Would this be a good choice? However I don’t know how you could select a codec per sip proxy in Xlite on a server that supports multiple codecs.

KM


#6

Highly dependent on your situation and what you are trying to do, so there is not a clear answer without additional detail on the application and architecture you would like to acheive.

It is possible to add/remove supported codecs on the server side and the X-Lite side, and to prioritize how they negotiate. It is possible to have different codecs by different services/accounts as well as different endpoints. Mix and match to your hearts content as Asterisk will transcode.

If you are running a small number of users on a large server, then CPU is not a concern, if you are looking to scale, then it is always something that should be addressed.


#7

Well as I outlined above a user could use whatever was the best codec for the carrier without trans coding.

How do you select different codecs per sip proxy in xlite? (I have asked in their forums) What soft phone do you prefer? (not a question really related to the original post.

km


#8

[quote=“kieranmullen”]Well as I outlined above a user could use whatever was the best codec for the carrier without trans coding.

How do you select different codecs per sip proxy in xlite? (I have asked in their forums) What soft phone do you prefer? (not a question really related to the original post.

km[/quote]

With Asterisk I use CounterPath’s Eyebeam, as it allows video with H263(+) as well. It is configurable there, and as best I know in the XLite client (been a while since I used it). Just look through the options and you should find it. The config interface for EyeBeam is entirely different than that for XLite.

Also, I do have to say, the interface for all of CounterPath’s softphones is just silly, recreating a phone interface in software entirely misses the point. I do use Gizmo with Asterisk, but since it can not register directly, its utility is not perfect.