Re: [MMUSIC] draft-jennings-mmusic-adjacent-grouping

[Christer Holmberg <[e-mail]>]

Hi, 

>>The grouping framework permits multiple groups to be formed 
>>with the same semantics. (E.g. you could define two audio/video 
>>groups, each to be lip synchronized.)
>> 
>>Analogously, one could presumably use the ADJ grouping semantic to 
>>form two independent groups of video streams.
>> 
>>OTOH, you might want to form two different groupings of m-lines that 
>>both map onto the same grid of devices. (For instance, a 
>>grouping of video m-lines and a corresponding grouping of audio m-lines.)
> 
>Yes. I just replied to Christer's email, he brought up the 
>same thing. We realized this open issue after the revision.
> 
>>But the a=media-grid-dims attribute doesn't provide any way to 
>>identify which group it applies to if there is more than one.
> 
>So it is a session-level attribute but this still does not 
>solve the audio-video overlay problem (suppose I have 3x2 
>screens - 6 video streams and 6x2 audio (stereo) streams).
> 
>If such an overlay is a desired feature, a general solution 
>needs to be identified.

It is also important to remember that there might not always be a 1-to-1 mapping between audio and video.

For example, you might have 3 displays, with one video stream for each display, but only 2 microphones, with one audio stream for each microphone.

Regards,

Christer