Re: [mediacapture-main] what is the default channelCount (#775)

One major aspect of a web spec is to describe what implementations are doing, or what they are trying to do.
That is what we are trying to achieve here. All browsers are selecting defaults and deciding when to apply them.
This is core to the getUserMedia algorithm.

> I'd put `channelCount` and `sampleRate` in the first category.

I think there is consensus for sampleRate, probably sampleSize as well.
There is apparently no consensus for channelCount yet. We should acknowledge this and seek for consensus.

> These decisions were clearly biased toward making sure the RTCPeerConnection sink didn't blow up.

That is true and we can always revisit this. We should also acknowledge this usecase is the major usecase right now so this decision is not absurd.
Also that is what implementations are doing, some websites are relying on it so we should document it.
You could try tweaking these defaults and go to some sites like webrtc.github.io/samples or appr.tc, the results will be poor.

For resizeMode, I doubt there is a meaningful OS default and we should strive for defining a good default.
It is for instance hurting interoperability that getUserMedia({video: {width:100, height:100}}) would not provide the same video size on different browsers because of different defaults for resizeMode.

> I don't think anyone has implemented anything like this. But it's something defining defaults would close the door on.

Should the need/usecase arise, we can revisit this issue. Implementations do change, as well as specifications.
The question might be whether we think this need will arise in the foreseeable future and if so how we would accommodate it.
My guess is that we do not have such a usecase yet.

We are really digging into https://github.com/w3c/mediacapture-main/issues/777 though.
This issue is focused on channelCount. I think we should first make progress on the easy one before trying to solve this one.

-- 
GitHub Notification of comment by youennf
Please view or discuss this issue at https://github.com/w3c/mediacapture-main/issues/775#issuecomment-789558023 using your GitHub account


-- 
Sent via github-notify-ml as configured in https://github.com/w3c/github-notify-ml-config

Received on Wednesday, 3 March 2021 09:07:40 UTC