Sound delay in i4b

[Dirk Thannhäuser]

On May 16, 2006, at 11:42 AM, Hans Petter Selasky wrote:

> Hi,
>
> On Tuesday 16 May 2006 11:19, Dirk Thannhäuser wrote:
>> On May 15, 2006, at 2:03 PM, Hans Petter Selasky wrote:
>>> On Monday 15 May 2006 12:20, Dirk Thannhäuser wrote:
>>>> On May 15, 2006, at 9:38 AM, Hans Petter Selasky wrote:
>>>
>>
>> I played around a lot with changing numbers, but i was not able to
>> get latency down.
>
>> Did you ever test with the asterisk echo test application?
>
> Yes, but only "ISDN-NT <-> Asterisk"

Thats my also my current Test Area. When this works i'll also check  
ISDN-TE <-> Asterisk
>
>> (maybe
>> that latency is only here a problem)
>
> There is an Asterisk application called MixMonitor, than can be  
> used to record
> calls.
>
> http://www.voip-info.org/wiki/view/MixMonitor
>
> Try recording the call, in .wav format:
>
> exten => ... , MixMonitor(my_file.wav)
>
> Then open up the wave file in a wave-file editor, or send it to me,  
> and try
> measure the echo delay.

Thats interesting. I should give it a try.

>
>> Is it possible that there is a
>> bug inside the application?
>
> There is a chance that "chan_capi.c" might be adding some extra  
> delay to the
> sound, when it bridges the call. You installed the latest chan_capi  
> also?

Yes. I did an upgreade to FreeBSD 6.1 an completely cleaned (removed  
an installed) the /usr/src tree. After that i checked out your latest  
revision of isdn4bsd and compiled/installed both i4b and chan_capi.

>
>> But on the other hand it worked fine with
>> the zaptel drivers.
>
> The zaptel drivers interrupt every millisecond I think, to move  
> data around.
> If you want that low latency, buy a HFC-4S and enable line  
> interconnect in
> 'capi.conf'.
>
>> I think i will need more time to study sources :-)
>
> --HPS