[Asterisk-video] H320

[Sergio García Murillo]

Olle E Johansson wrote:
> 9 jun 2006 kl. 10.43 skrev John Martin:
> 
>> Good point. I was wondering this on the way into work this morning.
>> I'm not sure how a lump of code that provided H.320 would be able to
>> be used in both PRI and BRI channels, or if it's an app, func,
>> channel or res? 
>> 
>> It brings up an interesting point about things like SIP, IAX and
>> H.323 they all use IP as the transport but have their own channel
>> drivers rather than a common IP channel driver and an
>> app/func/res... just an observation. So things that are IP based can
>> have their own channel drivers but ISDN based things can't :-)
> 
> Well, I was just a bit curious. It's not obviously a new channel seen
> with eyes from someone who does not know the details. Is the
> signalling very much different on an ISDN video call than an audio
> call?   
> 
> Unfortunately the API for MISDN and ZAP channels are very different.
> 
> For IAX2, SIP and H.323 the signalling is *very* different. Do
> remember though that SIP, H.323 and MGCP all share the RTP driver :-) 
> 

AFAIK, H324M and H320 just open a b channel of type Unrestricted digital information (instead of the Speech that it's the one that asterisk does), and on top of that channels it starts negotiating the protocol.
So having the isdn channel abstracted is a good thing as you don't need to handle the all the isdn internalls.
All we need is an isdn channel that offer a clean digital channel and does the correct q931 negotiation.

The idea of the application (for incomming calls for example) I have is one like this:

exten => s,1,Answer
exten => s,2,H324MTransfer(SIP/blablabla)

So you've got an isdn channel in the application with h324m, in which you start the h324m negotiation. 
You read from the channel pass it to the h324m code and viceversa. Once you have the call stablished, dial the sip peer and start reading the audio and video from the channle and passing it as input to the h324 which will mux it and send it to the isdn part, and continue reading from the isdn channel demuxing it and passing the audio/video to the sip channel.

Probably in H320 is a bit more tricky if you are going to do bonding
--------------------------------------------------------------------------------------
This message and any files transmitted with it are confidential and intended solely 
for the use of the individual or entity to whom they are addressed. No confidentiality 
or privilege is waived or lost by any wrong transmission. 
If you have received this message in error, please immediately destroy it and kindly 
notify the sender by reply email.
You must not, directly or indirectly, use, disclose, distribute, print, or copy any 
part of this message if you are not the intended recipient. Opinions, conclusions and 
other information in this message that do not relate to the official business of 
Ydilo Advanced Voice Solutions, S.A. shall be understood as neither given nor endorsed by it. 
--------------------------------------------------------------------------------------