[Freeswitch-users] Freeswitch stereo question(s)

Fri Jun 26 07:52:41 MSD 2015

FreeSWITCH will not do mono one direction and stereo another.  For
simplicity sake forget the distinction of stereo where the channels are
separate and mono duped into stereo.  If the chrome asks for stereo, fs
will do interleaved stereo both ways.   Chrome will send from a stereo mic
if echo can is off or it will double the mono signal to stereo.

If you call the conference with mono and conference is set to 2 channels it
will convert it accoringly.

If you are tapping the write stream and its not stereo interleaved audio,
then the channel is not operating in stereo mode.  You can tell by playing
an obvious stereo file in the conference and listen with stereo headphones.

On Thursday, June 25, 2015, Chris Mandra <mandra at gmail.com> wrote:

> Yeah, Chrome sums all to mono unless you kill auto echo cancellation. So,
> it seems like you're telling me that if the conference is set to stereo,
> there's no reason I should be seeing 960 samples / 20ms instead of 1920
> samples / 20 ms. When I first connect I see 1920, and then it switches to
> 960 sometime after I see the execute conference command in the cli. Is
> there an obvs reason why that would happen?
>
> On Thursday, June 25, 2015, Michael Jerris <mike at jerris.com
> <javascript:_e(%7B%7D,'cvml','mike at jerris.com');>> wrote:
>
>> We have support for stereo, we don't have support for 2 channel mono (ie
>> multiple m=audio lines in sdp).  Chrome doesn't either to my knowledge.  we
>> do allow receiving mono and sending stereo, we do this all day long.
>>
>> On Thursday, June 25, 2015, Chris Mandra <mandra at gmail.com> wrote:
>>
>>> Just a followup - Does freeswitch test for stereo? Does it differentiate
>>> between two channel mono and true stereo?
>>> If in the web RTC client SDP it's set so that it's sending mono and
>>> receiving stereo, what happens then? Does the core generally allow for that
>>> kind of asymmetry? I know that chrome sends mono bc of AEC.
>>> thanks,
>>> chris
>>>
>>> On Tue, Jun 23, 2015 at 10:03 PM, Chris Mandra <mandra at gmail.com> wrote:
>>>
>>>> Thanks Anthony. Question: what if in the web RTC client SDP you have it
>>>> set so that you are sending mono and receiving stereo. What happens
>>>> then? Does the core allow for that kind of asymmetry? It must,
>>>> right, because, for instance, I was sending a mono stream (or perhaps dual
>>>> mono) and hearing stereo in the conference on Friday.
>>>> Thanks, chris
>>>>
>>>>
>>>> On Tuesday, June 23, 2015, Anthony Minessale <
>>>> anthony.minessale at gmail.com> wrote:
>>>>
>>>>> If you call in and negotiate stereo, it uses stereo, if you try to
>>>>> play a mono audio stream it will resample and or mux it appropriately.
>>>>> If you call in with mono to mod_conference in stereo mode it will
>>>>> up-sample the input and the core will down-sample the output.
>>>>>
>>>>> If you are not using our verto demo with the stereo checked and
>>>>> calling with opus, there are not many other ways to turn stereo on.
>>>>>
>>>>>
>>>>>
>>>>> On Tue, Jun 23, 2015 at 5:46 PM, Chris Mandra <mandra at gmail.com>
>>>>> wrote:
>>>>>
>>>>>> Hi Anthony - thanks for the info.
>>>>>> So, "channels" is already set to 2 in
>>>>>> conf/autoload_configs/conference.conf.xml
>>>>>>
>>>>>>  <profile name="video-mcu-stereo">
>>>>>>
>>>>>>       <param name="domain" value="$${domain}"/>
>>>>>>
>>>>>>       <param name="rate" value="48000"/>
>>>>>>
>>>>>>       <param name="channels" value="2"/>
>>>>>>
>>>>>>       <param name="interval" value="20"/>
>>>>>>
>>>>>>       <param name="energy-level" value="200"/>
>>>>>>
>>>>>>
>>>>>> Does freeswitch test for actual stereo (as opposed to two channel
>>>>>> mono) and if it sees 2 chan mono does it downsample to mono?
>>>>>>
>>>>>> thanks!
>>>>>>
>>>>>> chris
>>>>>>
>>>>>> On Tue, Jun 23, 2015 at 6:26 PM, Anthony Minessale <
>>>>>> anthony.minessale at gmail.com> wrote:
>>>>>>
>>>>>>> Yes its interleaved.
>>>>>>>
>>>>>>> If you are calling into a conference you will have to run the
>>>>>>> conference in stereo or the channel will be downsampled to mono to match.
>>>>>>> Set channels to 2 in the mod_conference profile.
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> On Tue, Jun 23, 2015 at 5:21 PM, Chris Mandra <mandra at gmail.com>
>>>>>>> wrote:
>>>>>>>
>>>>>>>> Hi guys, I have another question about freeswitch, conferences and
>>>>>>>> stereo.
>>>>>>>>
>>>>>>>> When I make a webrtc call into 3500 on my freeswitch server,
>>>>>>>> mod_ladspa is reporting the number of samples as 1920 (20 ms stereo
>>>>>>>> interleaved I assume) fine for a few seconds, and then the number of
>>>>>>>> samples drops to 960 (20 ms mono) Any idea why this might be happening?
>>>>>>>>
>>>>>>>> Also, I have been assuming that stereo in freeswitch is interleaved
>>>>>>>> - is that the case? Is that assumption incorrect? If not interleaved, how
>>>>>>>> does fs handle stereo.
>>>>>>>>
>>>>>>>>
>>>>>>>> thanks!
>>>>>>>> chris
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> _________________________________________________________________________
>>>>>>>> Professional FreeSWITCH Consulting Services:
>>>>>>>> consulting at freeswitch.org
>>>>>>>> http://www.freeswitchsolutions.com
>>>>>>>>
>>>>>>>> Official FreeSWITCH Sites
>>>>>>>> http://www.freeswitch.org
>>>>>>>> http://confluence.freeswitch.org
>>>>>>>> http://www.cluecon.com
>>>>>>>>
>>>>>>>> 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       ♬ @anthmfs  ♬ @FreeSWITCH  ♬
>>>>>>>
>>>>>>> ☞ http://freeswitch.org/  ☞ http://cluecon.com/  ☞
>>>>>>> http://twitter.com/FreeSWITCH
>>>>>>> ☞ irc.freenode.net #freeswitch ☞ *http://freeswitch.org/g+
>>>>>>> <http://freeswitch.org/g+>*
>>>>>>>
>>>>>>> ClueCon Weekly Development Call
>>>>>>> [image: ☎] sip:888 at conference.freeswitch.org  [image: ☎]
>>>>>>> +19193869900
>>>>>>>
>>>>>>> ClueCon Testimonials <https://www.youtube.com/watch?v=9XXgW34t40s>
>>>>>>> ClueCon This Summer <https://www.youtube.com/watch?v=NLaDpGQuZDA>
>>>>>>>
>>>>>>>
>>>>>>> _________________________________________________________________________
>>>>>>> Professional FreeSWITCH Consulting Services:
>>>>>>> consulting at freeswitch.org
>>>>>>> http://www.freeswitchsolutions.com
>>>>>>>
>>>>>>> Official FreeSWITCH Sites
>>>>>>> http://www.freeswitch.org
>>>>>>> http://confluence.freeswitch.org
>>>>>>> http://www.cluecon.com
>>>>>>>
>>>>>>> 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
>>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>> mandra
>>>>>> c:410.258.5281
>>>>>>
>>>>>>
>>>>>> _________________________________________________________________________
>>>>>> Professional FreeSWITCH Consulting Services:
>>>>>> consulting at freeswitch.org
>>>>>> http://www.freeswitchsolutions.com
>>>>>>
>>>>>> Official FreeSWITCH Sites
>>>>>> http://www.freeswitch.org
>>>>>> http://confluence.freeswitch.org
>>>>>> http://www.cluecon.com
>>>>>>
>>>>>> 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       ♬ @anthmfs  ♬ @FreeSWITCH  ♬
>>>>>
>>>>> ☞ http://freeswitch.org/  ☞ http://cluecon.com/  ☞
>>>>> http://twitter.com/FreeSWITCH
>>>>> ☞ irc.freenode.net #freeswitch ☞ *http://freeswitch.org/g+
>>>>> <http://freeswitch.org/g+>*
>>>>>
>>>>> ClueCon Weekly Development Call
>>>>> [image: ☎] sip:888 at conference.freeswitch.org  [image: ☎] +19193869900
>>>>>
>>>>> ClueCon Testimonials <https://www.youtube.com/watch?v=9XXgW34t40s>
>>>>> ClueCon This Summer <https://www.youtube.com/watch?v=NLaDpGQuZDA>
>>>>>
>>>>
>>>>
>>>> --
>>>> mandra
>>>> c:410.258.5281
>>>>
>>>
>>>
>>>
>>> --
>>> mandra
>>> c:410.258.5281
>>>
>>
>
> --
> mandra
> c:410.258.5281
>

-- 
Anthony Minessale II       ♬ @anthmfs  ♬ @FreeSWITCH  ♬

☞ http://freeswitch.org/  ☞ http://cluecon.com/  ☞
http://twitter.com/FreeSWITCH
☞ irc.freenode.net #freeswitch ☞ *http://freeswitch.org/g+
<http://freeswitch.org/g+>*

ClueCon Weekly Development Call
☎ sip:888 at conference.freeswitch.org  ☎ +19193869900

https://www.youtube.com/watch?v=9XXgW34t40s
https://www.youtube.com/watch?v=NLaDpGQuZDA
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.freeswitch.org/pipermail/freeswitch-users/attachments/20150625/8e0e5670/attachment-0001.html 
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: image/png
Size: 3053 bytes
Desc: not available
Url : http://lists.freeswitch.org/pipermail/freeswitch-users/attachments/20150625/8e0e5670/attachment-0001.png 