Re: [mediacapture-main] How to implement web-compatible camera downscaling?

@guidou You mentioned video mirroring again, but https://github.com/w3c/mediacapture-main/issues/452 was closed a while ago as out of scope. FWIW I agree with @burnburn that `getUserMedia` is not a post-processing API.

> there were lots of popular bugs asking for support for ideal before Chrome 59

What's the more likely reason for that popularity?
 1. People wanted Chrome to follow FF + Edge in implementing `ideal` as the spec intended, or
 2. They wanted min-max ranges around their downscaled resolutions, because ... screen-sharing?

I think there's a disconnect here.

> Do you have evidence that this discrepancy (in which all browsers correctly implement the spec) is negatively affecting users?

See above. - The main complaint we hear is developers expecting `getUserMedia` to produce exactly the dimensions they specify "because it works in Chrome". It's a completely different model whether one scales at the source or [the](https://stackoverflow.com/questions/36961228/how-to-keep-11-aspect-ratio-video-all-the-time-in-webrtc/36962250) [sink](https://blog.mozilla.org/webrtc/fiddle-week-downscale-video-peerconnection/).

> controlling frame-rate adjustment separately from rescaling,

I think the spec works well enough here, actually. Drivers can offer divide-by-two, divide-by-three etc. decimated frame-rates with few side effects, whereas apps wouldn't know which ones are good, and they're close enough for most app use. I think it would be a mistake to give continuous frame-rate control to the app.

These divide-by rates can be added by the UA as well if the driver doesn't offer them. So "native" doesn't have to mean 100% native, just discrete (good) choices rather than a continuous value space devoid of hints.

This model should be enough to offer close-enough rescaling/decimating to satisfy most bit-needs, while at the same time avoiding sub-par choices, unless one implements a continuous set of settings dictionaries, drowning out the good choices, like Chrome has.

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Received on Tuesday, 8 August 2017 00:32:47 UTC