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Bug 9776 - Percentages for text positioning don't seem better than using the actual video dimensions. If you require integer percentages, then it doesn't work well for videos larger than 100px high. If not, then it's just an arbitrary resizing of the dimensions (sli
Summary: Percentages for text positioning don't seem better than using the actual vide...
Status: RESOLVED NEEDSINFO
Alias: None
Product: WHATWG
Classification: Unclassified
Component: HTML (show other bugs)
Version: unspecified
Hardware: Other other
: P3 normal
Target Milestone: Unsorted
Assignee: Ian 'Hixie' Hickson
QA Contact: contributor
URL: http://www.whatwg.org/specs/web-apps/...
Whiteboard:
Keywords:
Depends on:
Blocks:
 
Reported: 2010-05-20 09:22 UTC by contributor
Modified: 2012-07-18 18:42 UTC (History)
4 users (show)

See Also:

Attachments

Description contributor 2010-05-20 09:22:17 UTC 
Section: http://www.whatwg.org/specs/web-apps/current-work/#timed-track-cue-line-position

Comment:
Percentages for text positioning don't seem better than using the actual video
dimensions. If you require integer percentages, then it doesn't work well for
videos larger than 100px high. If not, then it's just an arbitrary resizing of
the dimensions (slightly less precise horizontally if you round off) and
you're more likely to have pixel measurements on hand than percentage
measurements (since Aegisub shows pixels). 

Posted from: 184.36.82.183
Comment 1 Ian 'Hixie' Hickson 2010-09-25 15:51:25 UTC 
What's the use case for precision to more than 1/100th of the video dimension?

We can't use pixels because it would mean that you couldn't use the same subtitle file for different resolution versions of the same video (consider e.g. YouTube videos which are often available in several sizes, but all have just one subtitle track).
Comment 2 Alexander Strange 2010-09-25 19:56:11 UTC 
This is mine - I meant that subtitle files could define their own pixel dimensions, and then coordinates could be resized to match the video.

This is how SSA works and it's quite successful - explicitly positioned text uses pixels, but text that just needs to be "center lower left" just has the alignment set to "center lower left", avoiding having to think about pixels and the size of the text box entirely.

Obviously none of this is a problem if you allow non-integer coordinates, since any size can be resized into 0-100% using floating point. And it would avoid needing to add a dimension header to the file as well.