[asterisk-dev] AST_FRAME_DIGITAL

[Klaus Darilion]

Steven Critchfield wrote:
> On Fri, 2007-09-14 at 17:15 +0200, Klaus Darilion wrote:
>> critch schrieb:
>>> The addon would then be a transcoder of H223 data to the demuxed
>>> audio/video/control frames using the library that is GPL licensed.
>>>
>>> This way is a lot more likely to get merged with the official releases
>>> as it is the asterisk way, and requires little changes to the core of
>>> the application.   
>> I agree. But extending the translation framework to translate 
>> AST_FRAME_VOICE(AST_FORMAT_H223) into AST_FRAME_VOICE(AST_FORMAT_AMR) 
>> and AST_FRAME_VIDEO(AST_FORMAT_H63_PLUS) is not easily done. Thus, to 
>> make 3G calls possible now I prefer the application, but if for example 
>> 1.6 allows translation between frame types then the application should 
>> be migrated in to translation framework.
> 
> So let us go about this in an interim manner.
> 
> Modify the ISDN channel drivers to hand up
> AST_FRAME_VOICE(AST_FORMAT_H223) from them to asterisk. Your application
> could request format AST_FORMAT_H223 such that there is no translation
> required. From here you continue your current development as you are.
> 
> The benefit here is that you get asterisk to the point of being able to
> native bridge 3g calls, and you get to worry only about your app for now
> while looking at how to get the translation layer to handle things
> better in the future. 
> 
> Also when you request from your application the format AST_FORMAT_H223,

how do I do this (in lines of code)?

klaus


> you can see if asterisk was able to handle the request. If the call
> wasn't a H223 call, asterisk couln't get you a H223 format and you will
> know you don't have the data you are looking for and can fail in a
> predictable manner. 
> 
> For instance, you could pass all your incoming calls into your 3g video
> application as a brute force detection this way. If your app gets 3g
> video stream, then it handles it the way you intend to, else it exits
> and allows the call to pass to the rest of your normal extension logic.
> 
> See how just a little effort yields lots of cool magic from the core
> knowing what it is transfering around?