Default font size `5vh` leads to very large cues for vertical videos

[jernoble]

The spec currently says:

The font shorthand property on the (root) list of WebVTT Node Objects must be set to 5vh sans-serif.

This value of 5vh leads to unreasonably large cues for vertical videos. See example here: http://jernoble.github.io/samples/bin/WebVTT/resize-aspect.html

Instead, the spec could use 5vmin (or actually, move away from redefining viewports entirely and use 5cqmin instead). The example above allows you to switch between 5vh and 5vmin to see the difference in behavior.

[jernoble]

[nigelmegitt]

vmin seems like the appropriate smallest change to fix the issue here.

[nigelmegitt]

Additional thought for consideration: should it depend on the text direction?

[himorin]

Additional thought for consideration: should it depend on the text direction?

Even with vertical writing text, the same absolute font size as horizontal one should be used, I suppose. Since, question should be what size of characters to be used for CC - even if it is vertical-set or horizontal-set, vertical-set text of CC in vertical video should have the same logic as horizontal-set text of CC in horizontal video, and for reverse. If we change to vmin, which is defined as minimum of vh or vw, I'd say that change considers both vertical-set or horizontal-set in the same priority.

[nigelmegitt]

Thanks @himorin , that makes sense: no dependency on the text direction, just the orientation of the video.

[gkatsev]

This seems reasonable to me.

Using 5cqmin also sounds reasonable. In this case, would we want to have a fallback of 5vmin in case container queries aren't implemented?

[jernoble]

Resurrecting this thread; lets tackle whether this should be vmin or cqmin in a separate issue, and just standardize 5vmin for now.

[gkatsev]

Sounds good to me. Incremental improvement for the win.