[asterisk-users] Re: Monitor, MixMonitor and volume levels

[Steve Davies]

*bump*

No suggestions at-all? Does anyone use this facility in a similar way
and NOT have problems?

Thanks,
Steve

On 11/3/06, Steve Davies <davies147 at gmail.com> wrote:
> Hi,
>
> I have started using the call recording facilities in Asterisk 1.2
> recently, and having worked out some of the foibles regarding call
> forwarding etc etc, I think I have a mostly working system.
>
> I do still seem to have a problem with recording volume though. It
> seems that all SIP call legs are recorded at "normal" volume, but all
> my Zap (ISDN) and IAX (via Provider -> ISDN) calls are recorded at a
> massively reduced volume.
>
> -> It does not matter whether the call originates inside or outside the box
> -> It does not matter which channel is Monitored (Zap, IAX or SIP)
> -> The caller/callee can hear each other fine regardless of the call
> source and destination.
> -> I also tried both Monitor and MixMonitor with the same results.
> -> The recording of the ISDN or IAX leg is so quiet that it is often
> impossible to hear.
> -> SIP to SIP records 100% okay
> -> Recording using different codecs makes no difference
> -> Voicemail recording volume is fine, regardless of call source.
>
> I considered using MixMonitor's volume settings, but cannot always
> identify which channel needs a volume boost (Local channels can
> obscure the call source or destination)
>
> I can use 'sox' to modify the levels to a usable point, but this
> amplifies background noise to a ridiculous degree so is not
> particularly satisfactory.
>
> Given that the call proceeds "normally" where is all of the volume
> being lost? We generally use aLaw end-to-end (which is the codec used
> on UK ISDN lines) so there should be almost no modification of the
> voice packets required at-all. Why does the recording differ from the
> audio being heard? I looked at the source and could see no obvious
> reason!
>
> Thanks for any pointers. I am happy to try experiments on our
> development system if it helps...
>
> Regards,
> Steve
>