Re: echoCancelation (sic)

On 3/29/14 12:46 AM, Randell Jesup wrote:
> The net result would be: Recordings: doesn't matter much, so On by 
> default (except maybe on Mobile).  Peerconnections: On by default, 
> unless told by the user to disable (off), or you know they're on a 
> headset (maybe off).  However, the advantage of all of this is small, 
> compared to the predictability benefit.

I agree with On by default (if supported obviously). Not sure I agree 
with On unless told by the user to disable (Off). The distinction only 
matters in the crazy case I brought up. e.g. if constraints require 
96KHz and the only mic to do that doesn't have AEC, AND the software 
doesn't do AEC, do you get the 96KHz mic or the regular one that does 
AEC? - I know, only implementers care at this level. ;-)

> I'll note this is generally semantically a *setting* more than a 
> *constraint*, though on Android you might have narrow-band-only HW 
> AECs available or WB with software AEC.

I agree most UAs will implement AEC in software, but ec is still a 
constraint. Currently, only peerIdentity is a property outside of the 
constraints model.

 From the client's perspective, these are all properties of the UA, 
grouped into sources. Some properties are inherent to a source (solidify 
past gUM), others are modifiable. The constraint model can handle that.

But there's an issue of how to express defaults in the spec. Let me use 
the WebIDL from my proposal for a sec:

dictionary MediaTrackConstraintSet {
     ..., ConstrainDouble volume;
};
typedef (double or ConstrainDoubleRange) ConstrainDouble;

This dictionary is reused both for constraints, capabilities and 
settings, for simplicity. However, it is overkill for the latter two. 
But capabilities and settings only need (deserve?) a simpler contract:

dictionary MediaTrackSettingSet {
     ..., double volume = 1.0;
};

Side-benefit: defaults are possible in the latter, not the former where 
it would mean the wrong thing (implicit constraint whose presence might 
fight with other constraints).

.: Jan-Ivar :.