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Re: [mediacapture-main] Browser's ability to dynamically change settings mistakenly removed

From: jan-ivar via GitHub <sysbot+gh@w3.org>
Date: Fri, 16 Sep 2016 17:15:42 +0000
To: public-media-capture-logs@w3.org
Message-ID: <issue_comment.created-247656374-1474046139-sysbot+gh@w3.org>
Perhaps I misunderstood. I interpreted @burnburn's request as wanting 
to restore the UAs ability to change a source within the envelope of 
existing constraints on it. If so, this would never throw 
`OverconstrainedError`. @burnburn is that what you meant?

@alvestrand With "external environment changes" you mean e.g. lighting
 effects on `frameRate`?

If so, then yes, fire `OverconstrainedEvent` in that case, but I don't
 think we should lump that together with "other requests". I'd expect 
new requests to fail rather than succeed and fire 
`OverconstrainedEvent` on other tracks of the same source, as that 
seems consistent with *SelectSettings* dictating that 
`applyConstraints` must leave things alone when it fails. E.g.:

```js
let clone = track.clone();
track.applyConstraints(tougherConstraints); // can fail, but can't 
overconstrain clone
```

(Conflicts are easier to imagine in browsers that don't add "virtual" 
settings through rescaling.)

Unfortunately, *SelectSettings* does not address existing constraints 
from other requests, though I saw just two ways to extrapolate how it 
should work, and having new concurrent requests fail rather than 
having them impact existing requests, seemed most consistent with 
`applyConstraints` leaving existing settings alone.

I basically interpret settings dictionaries that conflict with 
existing constraints from other requests to be impossible in the 
sentence "every possible settings dictionary".

Does that match everyone's expectation?

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Received on Friday, 16 September 2016 17:15:57 UTC

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