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Re: [mediacapture-main] How is adaptive frame rate to be handled?

From: Harald Alvestrand via GitHub <sysbot+gh@w3.org>
Date: Thu, 18 Jun 2015 09:33:15 +0000
To: public-media-capture-logs@w3.org
Message-ID: <issue_comment.created-113090102-1434619995-sysbot+gh@w3.org>
My immediate thought is that this is a case of "variation within a 
permitted range".

MediaCapabilities should show 10-30 (unless the drivers support 
downsampling, in which case it might be 0-30).
MediaSettings should return what the camera's drivers are currently 
giving. (I assume this is observable)
getUserMedia({video: { frameRate: { min: 20 }}}) should succeed if the
 camera's presently sending 30.
If the drivers don't support downsampling, getUserMedia({video: 
{frameRate: {max:20}}}) should fail if the camera's currently sending 
30.

If min:20 has been set, and the camera drops to 10, the 
overconstrained event should fire.

If the application is actually capable of operating usefully at 10 
fps, this example proves that it's a Bad Idea to specify a hard limit,
 which is why we have Ideal.

(At the moment, fitness distance is NOT reevaluated when rates change,
 so having a fitness distance computed to what the camera's currently 
producing is a good fit.)


-- 
GitHub Notif of comment by alvestrand
See 
https://github.com/w3c/mediacapture-main/issues/193#issuecomment-113090102
Received on Thursday, 18 June 2015 09:33:18 UTC

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