[Asterisk-Dev] libiax2 OK for production?

[Steve Underwood]

Steven Critchfield wrote:

>On Mon, 2005-01-31 at 20:00 -0500, Steve Kann wrote:
>  
>
>>Steve Underwood wrote:
>>    
>>
>>>This came up before. iaxcomm itself doesn't give such long delays, but 
>>>some sound card drivers do. My desktop machine give little latency. My 
>>>notebook gives a second or more. I think your sound card is most 
>>>likely the source of this latency. However, the fact you get better 
>>>results with miniphone means it is not a fundamental problem with the 
>>>card and driver (I assume you tried these tests on the same machine, 
>>>or they are meaningless). I believe miniphone and iaxcomm use 
>>>different ways to drive the sound card. Maybe iaxcomm is doing 
>>>something wrong. Sound cards normally work in a high latency mode, 
>>>which provides lots of buffering, and have to be switched to low 
>>>latency by the application. Maybe it isn't done correctly in iaxcomm 
>>>for all cards, or maybe there is some OSS/ALSA conflict. Do you know 
>>>what sound card hardware you have, and which driver?
>>>      
>>>
>>I haven't examined all the code, but I'm pretty sure the major 
>>parameters of what they're doing should be similar:
>>
>>They both use OSS
>>They both set the card to 8khz mono
>>They both set the card to full-duplex.
>>    
>>
>
>Okay, and with the comment of using FC3, you are probably getting piped
>through Alsa and it's OSS compatibility mode along with the extra
>buffering so Alsa can software mix the audio. 
>
>Might want to see if you can detect Alsa and get it into a low latency
>mode.
>  
>
That is probably relevant to getting the best results, but doesn't seem 
relevant to the original poster's problem. Both iaxcomm and miniphone 
use OSS, so they both suffer the extra delays you describe. This doesn't 
explain the differences he sees between applications. As you say, 
though, these things really should be using ALSA now, where it is available.

Regards,
Steve