[asterisk-dev] jitterbuffer and PLC

[nakaji at 02.246.ne.jp]

Hi, I have a question about jitterbuffer and PLC.

I use Asterisk 1.6.2.0 and 1.6.0.20 or older.
I use uLaw.

I want to use PLC on uLaw ,but it looks like not working.


My system map:
=============================================================================
                   SIP or IAX  /RTP                        SIP/RTP
    voice-file   - - - - - - - - - ->  (voice packet) - - - - - - - > voice     
 [ asterisk 2 ] -- # LOSS # -- # A # -- [ asterisk 1 ] -- # B # -- [ X-lite ]
                          
=============================================================================

I use two asterisk server. 
'asterisk 2' do "Playback(some voice file)"
'asterisk 1' do "jitter".
'asterisk 1' and 'asterisk 2' has trunked by sip or iax2.

X-lite call 3003 to asterisk 1,
 and asterisk 1 call 3000 to asterisk 2.
 
On the map, 
 at "LOSS" I caused packet loss 5%, 
 and at "A" and "B" I captured packet.

I thought number of packets at "B" would be same number from "asterisk 2".
And I thought number of packets at "A" would be 95% from "asterisk 2".  

But the result is different!

At "A" and "B" is the same number of packets as 95%.

No PLC ,No interpolations has made.
But on CLI,messages was "like that jitter and PLC work right" .




And I continued trying.

Now I reached 2 results.

1).
   Asterisk ver1.6 or more has bug ?

When you want to use jitter and PLC and want to see packet-log , you will 
set ' jblog=yes ' on 'sip.conf '.
But Asterisk can't make log-file.
In " /tmp/ " packet-log-file will be made, if jb-modules work correct.
Core module like 'abstract_jb.c' is different ,may be. Near around line 500, 
where jb write files.
Jb fails to write log in /tmp.
That codes is different from Asterisk ver 1.4.

I tested Asterisk ver 1.4.29, 1.6.0, 1.6.2.1(newest).
Only 1.4.29 , jblog=yes worked correct.
It looks like jb captured any frames.

ast_adaptive_jb_SIP#201-00000012--SIP#201-00000013.log
============================================
JB_PUT_FIRST {now=49}: Dropped frame with ts=392575 and len=20
 JB_GET {now=49}: now < next=2147483647
JB_PUT {now=70}: Dropped frame with ts=392595 and len=20
 JB_GET {now=70}: now < next=2147483647
JB_PUT {now=94}: Dropped frame with ts=392615 and len=20
 JB_GET {now=94}: now < next=2147483647
JB_PUT {now=104}: Queued frame with ts=392635 and len=20
 JB_GET {now=104}: now < next=144
JB_PUT {now=124}: Queued frame with ts=392655 and len=20
...
...
...
=============================================

But  Asterisk ver 1.6.0,1.6.2.1  ,  jb can't write logs.


2).
 When use Asterisk ver 1.4.29, jb looks like work correct. But actually , it 
doesn't work,may be.


As I mentiond at No1, When I use Asterisk1.4.29, jb looks work correct.
Because packet-log-file will be made ( as written in aabstract_jb.c ).
And on CLI shows messages.
like this.
===============================================
[Jan 20 16:15:03]     -- adaptive jitterbuffer created on channel 
SIP/201-0000000e
*CLI>
*CLI> [Jan 20 16:15:23]     -- adaptive jitterbuffer destroyed on channel 
SIP/88208ABC-0000000f
===============================================

But actually, when I captured packet (by wireshark) ,and lossed 5% packets 
before flow into Asterisk,
Same number of packets( as lossed 5% ) flow out from Asterisk.
No Interpolations has made,actually.
 However, in  jb's  packet-log-file, "Interpolated frame " has written.
-------------------------------------------------------------------------
 JB_GET {now=2001}: Delivered frame with ts=1720 and len=20
 JB_GET {now=2003}: now < next=2021
 JB_GET {now=2004}: now < next=2021
JB_PUT {now=2008}: Queued frame with ts=1780 and len=20
 JB_GET {now=2009}: now < next=2021
 JB_GET {now=2013}: now < next=2021
 JB_GET {now=2020}: now < next=2021
 JB_GET {now=2021}: Interpolated frame with len=20
 JB_GET {now=2024}: now < next=2041
 JB_GET {now=2033}: now < next=2041
JB_PUT {now=2033}: Queued frame with ts=1800 and len=20
 JB_GET {now=2034}: now < next=2041
------------------------------------------------------------------------
But actually, PLC didn't work.

So if anyone who could work PLC correct, pls tell me the version and how to 
set up.
or pls tell me where is wrong.

on my sip.conf
===============
jbenable=yes
jbforce=yes
jbmaxsize=100
jbresyncthreshold=2000
jbimpl=adaptive
jblog=yes
===============

I also tried,
jbresyncthreshold= -1 or 1000
jbimpl=fixed


Rgards;