[Freeswitch-users] Audio clipping in mod_conference

Anthony Minessale anthony.minessale at gmail.com
Fri Nov 4 01:05:30 MSK 2011


well waste bandwidth became obsolete on oct 4th

You could test your theory by using a 30ms/20ms phone instead.
You should really remove variables until you come up with something.

Basically the default FS conf on sip:888 at conference.freeswitch.org  is
running the default params with 200 as default energy.
So call that first and see if you get the same issue because we have 30+
people call there every wednesday without incident and we literally spend
like 12 hours a day on the same server for private development.

Then setup a vanilla out of the box FS build and try exten 3000
The conference. and see if you get your problem, try other phones etc.

look at all the variables to see what you may be doing differently than
most people who do not experience your issue.






2011/11/3 Roland Hänel <roland at haenel.me>

> Yes, I am on a current GIT (about 2 weeks old), and I have waste-bandwidth
> for every subscriber, and a packet capture confirms that FS sends RTP
> permanently. So jitter buffers shouldn't be an issue here.
>
> Even *if* jitter buffers would be recharging, that would only lead to a
> small delay, but not to audio being clipped (i.e., lost), right?
>
> My packet traces show that there are different ptime's involved
> (FreeSwitch is on 20ms by default, some phones have 30ms). Could that
> contribute to the issue?
>
> Roland
>
>
> 2011/11/3 Anthony Minessale <anthony.minessale at gmail.com>
>
>> it's not,
>>
>> most likely you have a jitterbuffer on your phone that is recharging when
>> you start talking.
>> are you on the latest GIT where we have the waste bandwidth flag
>> on permanently for all callers?
>> To avoid problems like this conferences now always send rtp to people
>> even when they are not getting any useful input.
>>
>>
>> 2011/11/3 Roland Hänel <roland at haenel.me>
>>
>>> Anthony,
>>>
>>> The problem is not that audio is clipped because its "too silent", so
>>> adjusting the value seems to be the wrong handle for this problem.
>>>
>>> It seems that the time needed to make the decision (regardless of the
>>> energy threshold value) is the core of the issue, i.e. the level may bei
>>> 100, 200 or 300, it takes some XX ms to detect talking and all audio that
>>> happens before the detection gets lost. Right?
>>>
>>> Greetings,
>>> Roland
>>>
>>>
>>>
>>> 2011/11/3 Anthony Minessale <anthony.minessale at gmail.com>
>>>
>>>> The setting is an arbitrary number of the energy score required to
>>>> count as talking.
>>>>
>>>>
>>>> check your environments, its very specific to the surroundings.
>>>> We run it at 200 in the main FS conf and its rarely an issue.
>>>>
>>>>
>>>>
>>>>
>>>> 2011/11/3 Roland Hänel <roland at haenel.me>
>>>>
>>>>> Setting it to 10 or so doesn't help, it seems that just the threshold
>>>>> of detection is changed (ok, that's what is expected), not the time until
>>>>> the decision is made.
>>>>>
>>>>> The audio clipping is a timing issue.
>>>>> Does there exist something like a "minimum time" that this algorithm
>>>>> needs to detect talking after silence? What happens to the audio that was
>>>>> sent by that member during this time, does.the algorithm discard that?
>>>>>
>>>>> Greetings,
>>>>> Roland
>>>>> Am 03.11.2011 18:20 schrieb "Anthony Minessale" <
>>>>> anthony.minessale at gmail.com>:
>>>>>
>>>>>  yes? set it to something between what it was and 0 ?
>>>>>>
>>>>>>  <param name="energy-level" value="300"/>
>>>>>>
>>>>>> try 200 100 50 ?
>>>>>>
>>>>>> 2011/11/3 Roland Hänel <roland at haenel.me>
>>>>>>
>>>>>>> Hi,
>>>>>>>
>>>>>>> During thorough testing of our conference solution which is based on
>>>>>>> FreeSwitch / mod_conference, we noticed some 'audio clipping' during the
>>>>>>> conference. Typically, if a conference member didn't have audio for some
>>>>>>> time and then begins to speak, the first syllable will be clipped and
>>>>>>> cannot be heard by the other conference participants.
>>>>>>>
>>>>>>> We ruled out a number of possible causes, and finally discovered
>>>>>>> that the energy level detection algorith seems to be the source of the
>>>>>>> problem. Setting the energy level for all participants to "0" heals the
>>>>>>> problem (of course now the noise might be higher since every participant's
>>>>>>> noise contributes to the total noise), but this setting is not very useful
>>>>>>> since the "talking detection" seems to rely on the same level, i.e. with
>>>>>>> energy "0", all members are marked talking all the time (which effectively
>>>>>>> renders the "talking" display useless).
>>>>>>>
>>>>>>> Is there any chance to tune the energy level detection time (!), or
>>>>>>> to de-couple talking detection an energy level detection in FreeSwitch?
>>>>>>>
>>>>>>> Best regards,
>>>>>>> Roland
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> FreeSWITCH-users mailing list
>>>>>>> FreeSWITCH-users at lists.freeswitch.org
>>>>>>> http://lists.freeswitch.org/mailman/listinfo/freeswitch-users
>>>>>>> UNSUBSCRIBE:
>>>>>>> http://lists.freeswitch.org/mailman/options/freeswitch-users
>>>>>>> http://www.freeswitch.org
>>>>>>>
>>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>> Anthony Minessale II
>>>>>>
>>>>>> FreeSWITCH http://www.freeswitch.org/
>>>>>> ClueCon http://www.cluecon.com/
>>>>>> Twitter: http://twitter.com/FreeSWITCH_wire
>>>>>>
>>>>>> AIM: anthm
>>>>>> MSN:anthony_minessale at hotmail.com
>>>>>> GTALK/JABBER/PAYPAL:anthony.minessale at gmail.com
>>>>>> IRC: irc.freenode.net #freeswitch
>>>>>>
>>>>>> FreeSWITCH Developer Conference
>>>>>> sip:888 at conference.freeswitch.org
>>>>>> googletalk:conf+888 at conference.freeswitch.org
>>>>>> pstn:+19193869900
>>>>>>
>>>>>>
>>>>>> FreeSWITCH-users mailing list
>>>>>> FreeSWITCH-users at lists.freeswitch.org
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>>>>>> UNSUBSCRIBE:
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>>>>>>
>>>>>>
>>>>>
>>>>> FreeSWITCH-users mailing list
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>>>>> http://www.freeswitch.org
>>>>>
>>>>>
>>>>
>>>>
>>>> --
>>>> Anthony Minessale II
>>>>
>>>> FreeSWITCH http://www.freeswitch.org/
>>>> ClueCon http://www.cluecon.com/
>>>> Twitter: http://twitter.com/FreeSWITCH_wire
>>>>
>>>> AIM: anthm
>>>> MSN:anthony_minessale at hotmail.com
>>>> GTALK/JABBER/PAYPAL:anthony.minessale at gmail.com
>>>> IRC: irc.freenode.net #freeswitch
>>>>
>>>> FreeSWITCH Developer Conference
>>>> sip:888 at conference.freeswitch.org
>>>> googletalk:conf+888 at conference.freeswitch.org
>>>> pstn:+19193869900
>>>>
>>>>
>>>> FreeSWITCH-users mailing list
>>>> FreeSWITCH-users at lists.freeswitch.org
>>>> http://lists.freeswitch.org/mailman/listinfo/freeswitch-users
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>>>> http://lists.freeswitch.org/mailman/options/freeswitch-users
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>>>>
>>>>
>>>
>>>
>>> --
>>> Gruß,
>>> Roland
>>>
>>>
>>>
>>>
>>> FreeSWITCH-users mailing list
>>> FreeSWITCH-users at lists.freeswitch.org
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>>> http://www.freeswitch.org
>>>
>>>
>>
>>
>> --
>> Anthony Minessale II
>>
>> FreeSWITCH http://www.freeswitch.org/
>> ClueCon http://www.cluecon.com/
>> Twitter: http://twitter.com/FreeSWITCH_wire
>>
>> AIM: anthm
>> MSN:anthony_minessale at hotmail.com
>> GTALK/JABBER/PAYPAL:anthony.minessale at gmail.com
>> IRC: irc.freenode.net #freeswitch
>>
>> FreeSWITCH Developer Conference
>> sip:888 at conference.freeswitch.org
>> googletalk:conf+888 at conference.freeswitch.org
>> pstn:+19193869900
>>
>>
>> FreeSWITCH-users mailing list
>> FreeSWITCH-users at lists.freeswitch.org
>> http://lists.freeswitch.org/mailman/listinfo/freeswitch-users
>> UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-users
>> http://www.freeswitch.org
>>
>>
>
>
> --
> Gruß,
> Roland
>
>
>
>
> FreeSWITCH-users mailing list
> FreeSWITCH-users at lists.freeswitch.org
> http://lists.freeswitch.org/mailman/listinfo/freeswitch-users
> UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-users
> http://www.freeswitch.org
>
>


-- 
Anthony Minessale II

FreeSWITCH http://www.freeswitch.org/
ClueCon http://www.cluecon.com/
Twitter: http://twitter.com/FreeSWITCH_wire

AIM: anthm
MSN:anthony_minessale at hotmail.com
GTALK/JABBER/PAYPAL:anthony.minessale at gmail.com
IRC: irc.freenode.net #freeswitch

FreeSWITCH Developer Conference
sip:888 at conference.freeswitch.org
googletalk:conf+888 at conference.freeswitch.org
pstn:+19193869900
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