[Asterisk-Dev] SIP Jitter Buffer Testing

[Zoa]

The jitter buffer he tested it with is a fixed size version, so as long
as there is no packetloss (or delay larger than the size of the buffer)
and thus no PLC is used, it might be better than the original.
The fixed size jitter buffer was only made to easy the search for the
memory leak, (without succes), i don't think its a good idea to rely on
it for faxing is it will probably change again in the future.

Cheers,

Zoa.

------------------
http://www.asteriskguru.com

steve at daviesfam.org wrote:

>On Fri, 16 Sep 2005, George Pajari wrote:
>
>
>
>>It goes without saying that on most connections, getting faxes through
>>without the jitter buffer is almost impossible. The jitterbuffer makes a
>>phenomenal difference. But we are still experiencing more problems than
>>we should and have some questions on how to best proceed.
>>
>>
>
>
>George:
>
>The jitter buffer logic really isn't designed at all for the goal of
>correctly passing modem signals.  I don't think you are experiencing more
>problems than you should; even if the jitter buffer works perfectly
>(actually, especially if it works perfectly) it won't pass modem signals
>consistently.
>
>Here's some reasons why:
>
>1) If a frame doesn't arrive in time, it makes up a frame based on a
>simple model of what sounds OK to the human ear.  Certainly won't fool
>your fax machine.
>
>2) If the code needs to expand or contract the jitter buffer, stunts are
>pulled with the audio that tries to hide the change.  Death to your fax
>machine's signal.
>
>3) If the jitter buffer grows too large, latency on the connection will
>break certain time-critical handshakes in the protocol between the two fax
>machines.
>
>Speaking with some confidence on behalf of Steve Kann: Passing modem
>signals is not, and is very unlikely to become a design goal for the
>jitter buffer.
>
>Regards,
>Steve
>_______________________________________________
>Asterisk-Dev mailing list
>Asterisk-Dev at lists.digium.com
>http://lists.digium.com/mailman/listinfo/asterisk-dev
>To UNSUBSCRIBE or update options visit:
>   http://lists.digium.com/mailman/listinfo/asterisk-dev
>
>

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 254 bytes
Desc: OpenPGP digital signature
Url : http://lists.digium.com/pipermail/asterisk-dev/attachments/20050917/4c013455/signature.pgp