Re: [webrtc-pc] Spec says scaleResolutionDownBy must default to 1, but browsers differ (#2535)

> In Firefox, when scaleResolutionDownBy is not specified, it is always assumed to be 1.0, regardless of the method (e.g. setParameters, addTransceiver, etc.)?

@aboba Yes (Firefox [only supports](https://bugzil.la/1396918) setting via setParameters atm.)

> When there is more than one simulcast encoding, the Chrome default behavior in addTransceiver is to assume a default scaling ratio of 2:1. However, when scaleResolutionDownBy isn't specified in setParameters(), is a default value of 1.0 assumed, or some other value (e.g. the existing value)?

No, 1.0 is **_not_** assumed in Chrome, or the fiddle [above](https://github.com/w3c/webrtc-pc/issues/2535#issue-627794824) would have produced 3 same-size videos (it does not, instead showing the 2:1 ratio (large, medium, small).

The behavior is the same if I [comment out setParameters entirely & dump the params](https://jsfiddle.net/jib1/yvg81otc/46/) showing that the defaults are unharmed and invisible (not exposed in `getParameters`).

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Received on Monday, 1 June 2020 19:02:23 UTC