Need more attributes in MediaDeviceInfo

[ibc]

Let assume an app in which the user can choose the webcam device in a drop list and get a preview of it. If he selects a front camera, the preview <video> element must enable CSS transform: scaleX(-1); (mirror effect). If he selects a back/rear camera, no mirror effect must be applied.

This seems to be a very common scenario. But AFAIK it's unfeasible with the current API.

The drop list is filled with enumerateDevices() by filtering device.kind === 'videoinput', and (assuming a previous permissions prompt) it can display the device.label of the video devices. But from the API point of view, the app has no way to know whether a device in the list is a front or a back camera.

So, the user chooses one, the app gets its device.deviceId and calls getUserMedia() with video: { exact: device.deviceId }. At that point, the app has no way to know whether it must apply the "mirror effect" to the local video or not.

I know about some developers (including me) matching /(back|rear)/i to the device.label. Hope the API can provide something much better than that. Things would be much easier (or just feasible) if DeviceMediaInfo includes more fields such as facingMode.

I may understand that the proper way to go is by calling getUserMedia() with the choosen deviceId (as above) and then inspect the retrieved video MediaStreamTrack.getConstraints(), which seems to include facingMode. However (at least in Firefox which is closer to the spec) track.getConstraints().facingMode is an empty object. Is that because getUserMedia() was NOT called with a facingMode constrain?

If so, the same problem as the above described applies.

[stefhak]

I think you should call track.getSettings() if you want to read out e.g. the facingMode.

[ibc]

Certainly I missed track.getSettings(). Hope browsers properly implement it soon, as no one of them provide the facingMode setting.

The spec is ok then. It's just lack of implementation in browsers. Closing the issue. Thanks.

[stefhak]

Do you plan to file issues on Chrome & Firefox? Would be interesting to know their implementation plan.

[ibc]

Yes, I'll do eventually and update here when done.