[asterisk-users] Call Recording audio file quality query

[Tilghman Lesher]

On Tuesday 08 February 2011 06:34:56 Sherwood McGowan wrote:
> On Tue, Feb 8, 2011 at 6:01 AM, <faisal at vopium.com> wrote:
> > But if you are getting calls all the way on VoIP then you can have
> > calls in HD audio using HD audio codec on all locations (Server and
> > Client). In that case you either need use some available 3rd party
> > solution which uses packet capturing to trace the calls and record
> > call using packet capture and assembling regardless of server as
> > asterisk still will not be able to record call in HD but some other
> > switches like FreeSWITCH can do it or you need to write your own app
> > like it.
> 
> It's not difficult at all to perform what you're referring to..If you
> have the hardware...
> 
> A simple way is to have a port on your main network switch/router that
> will "firehose" the traffic the device interacts with In case someone
> reading this doesn't know, I'm talking about having a port that just
> makes a copy of EVERY PACKET that the device "sees" and sends those
> copies out over the port that you've set up for the purpose..It just
> GUSHES data over that port...like a firehose just gushes out all the
> water it possibly can... LOL
> 
> Anyway, once your data is being mirrored over that firehose, send it to
> a dedicated "recording" server...all it has to do is find the signaling
> packets for each call and then just dump the "payload" from the RTP.
> It'll come out exactly as it was transported within RTP...in the codec
> the call set up....
> 
> I may be wrong, but I'm fairly sure that Asterisk can write a filetype
> for almost any of it's codecs...I know it can READ audio files that are
> encoded in GSM, uLaw (ul), aLaw (al), G726 and G729 formats (.g729,
> g.726)...etc...
> 
> If the "DECoding" portion is there, there's almost GOT to be the
> "enCOding" functionality...

Actually, the writing of encoded voice has nothing to do with codecs.
The format modules simply expect a particular type of packet to be
fed in, and they simply reformat the audio (without transcoding) to be
stored on disk.  One caveat is that the format in which they are stored
on disk is not guaranteed to be a standard format that is at all useful
to outside utilities; just that Asterisk can read it off disk and reassemble
the packets.

-- 
Tilghman