Get user media constraints resizemode

[hamishwillee]

FF144 added a new constraint parameter resizeMode for use with MediaDevices.getUserMedia() and getDisplayMedia().

This allows a developer to specify whether the video from the camera should be cropped and/or downscaled to match other constraints, which may be natively supported by the camera - essentially gives them what they ask for rather than what the camera is capable of delivering. It also allows them to specify that it doesn't want scaling.

This updates the relevant docs (First two commits are layout only).

The main changes are to:

• Better cross-link MediaTrackConstraints which is where the constraint is documented to make it clear that it is also used in these methods (not just some others).
• Provide an example explaining the downscaling.

Related docs work can be tracked in #41132

[github-actions]

Preview URLs

• /en-US/docs/Web/API/MediaDevices/getDisplayMedia
• /en-US/docs/Web/API/MediaDevices/getUserMedia
• /en-US/docs/Web/API/MediaTrackConstraints

Flaws (2)

Note! 2 documents with no flaws that don't need to be listed. 🎉

URL: /en-US/docs/Web/API/MediaTrackConstraints
Title: MediaTrackConstraints
Flaw count: 2

• unknown:
  • Error serializing baseline for numeric-seperators: missing field description``
  • Error serializing baseline for single-color-gradients: missing field description``

External URLs (2)

URL: /en-US/docs/Web/API/MediaDevices/getUserMedia
Title: MediaDevices: getUserMedia() method

• https://w3c.github.io/mediacapture-main/ (1 time) (Note! This may be a new URL 👀)

---

URL: /en-US/docs/Web/API/MediaTrackConstraints
Title: MediaTrackConstraints

• https://w3c.github.io/mediacapture-main/ (1 time) (Note! This may be a new URL 👀)

(comment last updated: 2025-09-19 01:08:22)

[hamishwillee]

@wbamberg I added this line since last review to make it clear that there is no explicit default - just a calculation that works out what would be best based on the constraints with none and the constraints with crop-and-scale set.

[wbamberg]

👍 thank you Hamish!