[Freeswitch-users] Recording G729

Steven Ayre steveayre at gmail.com
Tue Nov 26 12:07:33 MSK 2013


>
> Also: even if you record to wav, and both legs are something else (eg
> g729, iLBC, whatever), would the recording transcoding not undo the
> potential benefit of not having to transcode between a- and b-leg?


You require extra CPU (and with mod_com_g729 more licenses) but can get
better quality as a result. It's a trade-off.

Depending on what you're doing you could look at mod_native_file, which'll
play a file pre-recorded in the codec in use and fallback to WAV if it
isn't found. For example if it's something like IVR options.

It probably isn't worth it for things like voicemail though.

-Steve



On 26 November 2013 04:07, Kees Varekamp <kees at mroffice.org> wrote:

> OK I'll try and check if that helps - although CPU really doesnt seem an
> issue. Another thought: if you run lame on the same server wouldn't it get
> a comparable cpu load anyway? Or even worse since it is batch wise?
>
> Also: even if you record to wav, and both legs are something else (eg
> g729, iLBC, whatever), would the recording transcoding not undo the
> potential benefit of not having to transcode between a- and b-leg?
>
> Thanks,
>
> Kees
>
>
> On Tue, Nov 26, 2013 at 4:09 PM, Yuri Ritvin <yuri.ritvin at gmail.com>wrote:
>
>> You'll better record in a standard WAV format and will convert it into
>> MP3 with lame (you need to install lame, of course, onto your server) thus
>> off-loading some burden from the freeswitch processing. Say you record WAV
>> files into a folder /opt/freeswitch/sounds/recorded and wanna have MP3
>> files in a folder /opt/freeswitch/sounds/recorded/mp3, then you create the
>> following script and run it via crontab every 15 minutes (or any desired
>> time interval):
>>
>> #!/bin/bash
>> cd /opt/freeswitch/sounds/recorded
>> for i in `find . -name "*.wav" -cnewer mp3|cut -d/ -f2|cut -d. -f1`
>> do
>> lame -S -h --resample 16 -b 24 $i.wav mp3/$i.mp3
>> done
>>
>>
>>
>> On Mon, Nov 25, 2013 at 9:39 PM, Kees Varekamp <kees at mroffice.org> wrote:
>>
>>> Hi all,
>>>
>>> I'm suffering from poor sound quality on my setup, using GSM on the
>>> a-leg and PCMU on the b-leg. I'm thinking it's mostly bandwidth/network
>>> related, so I'm considering switching to G729 on both legs, as that is the
>>> only compressed codec that the b-leg supports (it's a sip gateway).
>>>
>>> But a complicating factor is that the calls need to be recorded in mp3.
>>>
>>> So I have some questions that I hope someone here can answer:
>>>
>>>
>>>    - Does transcoding (for example GSM<>PCMU) negatively affect the
>>>    sound quality, even when the CPU seems to be ok with it?
>>>    - If yes, does recording 2 legs using the same codec (say G729) to a
>>>    different sound format (say mp3) have the same (negative) effect?
>>>    - When you use G729 on both legs (using mod_com_g729), it is even
>>>    possible to record to mp3?
>>>
>>>
>>> Thank you,
>>>
>>> Kees
>>>
>>>
>>> _________________________________________________________________________
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>>> http://www.freeswitchsolutions.com
>>>
>>> 
>>> 
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>>
>> _________________________________________________________________________
>> Professional FreeSWITCH Consulting Services:
>> consulting at freeswitch.org
>> http://www.freeswitchsolutions.com
>>
>> 
>> 
>>
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>>
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>>
>
>
> --
> Kees Varekamp
> *MROffice Director*
> 44 Castleford street, 0604, Auckland, New Zealand
> Phone: +6492821656
> Skype: kees.mroffice
> Web: mro <http://mro-global.com>ffice.org
>
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>
> _________________________________________________________________________
> Professional FreeSWITCH Consulting Services:
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> http://www.freeswitchsolutions.com
>
> 
> 
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