W3C home > Mailing lists > Public > public-media-capture@w3.org > August 2015

Re: Do we need a powerNetworkFrequency constraint?

From: Harald Alvestrand <harald@alvestrand.no>
Date: Mon, 31 Aug 2015 23:55:09 +0200
Message-ID: <55E4CD3D.8070707@alvestrand.no>
To: public-media-capture@w3.org
Just to wrap this:

After some more discussion I've concluded that this is a bad idea, and
I'm withdrawing the suggestion.

If a camera needs information about the power line frequency, that
information should be configured per machine, and not per camera capture.

I still want comments on the thread about how to deal with new
constraint proposals, however....

Harald


Den 25. aug. 2015 07:47, skrev Harald Alvestrand:
> Most cameras seem to have some place in their API where you set the line
> power frequency of the area you live in; this is used to suppress
> flicker from fluorescent or LED-based lighting fixtures.
> 
> Many times, the OS or the browser can make a guess at the right power
> frequency based on environment factors like timezone or location, and
> everything's OK.
> 
> But sometimes it's wrong. And it makes people unhappy.
> 
> One option is to have a way to override the setting from the application
> if needed; we can, for instance, have a tri-state constraint, mirroring
> the camera APIs:
> 
> powerNetworkFrequency = "50Hz", "60Hz", "default"
> 
> (I don't see a case for allowing "powerNetworkFrequency=200", which
> would be the case if we made it a number.... even though there are
> railway power grids at 16 2/3 Hz, they're rare enough that we should
> ignore them for simplicity's case).
> 
> What do people think?
> 
> (Also filed as https://github.com/w3c/mediacapture-main/issues/234)
> 
> Harald
> 
Received on Monday, 31 August 2015 21:55:40 UTC

This archive was generated by hypermail 2.4.0 : Friday, 17 January 2020 16:26:33 UTC