[Asterisk-video] App_videoswitch

[Mihai Balea]

On Jun 4, 2007, at 2:05 PM, Charles Williams wrote:

>
>> -----Ursprüngliche Nachricht-----
>> Von: Development discussion of video media support in Asterisk  
>> <asterisk-video at lists.digium.com>
>> Gesendet: 04.06.07 16:45:17
>> An: Development discussion of video media support in Asterisk  
>> <asterisk-video at lists.digium.com>
>> Betreff: Re: [Asterisk-video] App_videoswitch
>
>
>>
>>
>> On Jun 4, 2007, at 4:10 AM, Charles Williams wrote:
>>>
>>> well. actually there won't be much need for negotiation or
>>> transcoding as the codec will be 1 codec that we decide (h.264) all
>>> asterisk will have to do is relay the stream. do you know if that
>>> would be a problem?
>> We have a similar approach in our systems, where we only use one
>> video codec (Theora) with no transcoding.  You will probably not be
>> able to successfully negotiate a video codec over IAX, but my guess
>> is if you push video frames over an already established audio
>> connection, things might just work.  app_conference does not do any
>> video codec check or negotiation - any video frame is passed along to
>> the eligible conference members regardless of what's inside.
>>
>> Mihai
>
> mihai,
>
> that is exactly what we need to do except with the h.264 codec (or  
> is Theora better quality/bandwidth wise than h.264?). how did you  
> get yours working?
>
> chuck

On technical terms, H.264 is significantly better than Theora.  The  
quality is slightly better at the same bandwidth, but what really  
makes it a better choice is the fact that it was designed with  
streaming in mind. On the other hand, the licensing proved to be a  
pain, which is why we decided to go with Theora.

We did a bunch of changes to Asterisk in order to get this working.   
We first added Theora to the list of accepted codecs.  Then we  
changed the way codec selection works, so we could get some  
rudimentary video codec negotiation going in IAX2.  That part is not  
very polished and I don't think it is worth submitting upstream,  
since IAX video codec negotiation is going to get a lot better in the  
following months (as a result of the discussions we had at Astridevcon).

Mihai