Re: [media-and-entertainment] Compositable Video Content (#103)

Regarding:

> other video layers could be delivered with an assured fidelity, e.g., text overlays, lower third content, and news tickers.

and

> Foreground layers could be capable of having hypertext selected from them or of otherwise being interacted with, e.g., clicked upon. As considered, this type of video layer might provide bounding boxes or silhouettes, perhaps with identifiers unique to the video container or stream.

it's worth noting that the HTML model of the `<video>` element does not support compositing child content elements. As the [spec](https://html.spec.whatwg.org/multipage/media.html#the-video-element) says:

>Content may be provided inside the [video](https://html.spec.whatwg.org/multipage/media.html#the-video-element) element. User agents should not show this content to the user; it is intended for older web browsers which do not support [video](https://html.spec.whatwg.org/multipage/media.html#the-video-element), so that text can be shown to the users of these older browsers informing them of how to access the video contents.

Video players currently have to work around this by providing content in a separate part of the DOM and using styling to position that content over the video. In that sense the `<video>` element is unlike other content elements, arguably unhelpfully.

I think the use case is understandable, but I would suggest that delivering text with an "assured fidelity" can be an accessibility anti-pattern. It would be better to take advantage of the web platform to be able to allow client side rendering of especially text but also styled graphics over the video, so that their contents and semantics are visible to assistive technology, and so that users can modify the presentation to meet their accessibility needs, e.g. using a stylesheet.


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Received on Tuesday, 22 August 2023 14:04:33 UTC