- From: Eric Carlson <eric.carlson@apple.com>
- Date: Thu, 31 Mar 2011 07:49:03 -0700
- To: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
- Cc: Ian Hickson <ian@hixie.ch>, Mark Watson <watsonm@netflix.com>, "public-html-a11y@w3.org" <public-html-a11y@w3.org>
On Mar 30, 2011, at 9:22 PM, Silvia Pfeiffer wrote: > But I am told, UAs render them simply over each other > at the top left corner. In any case, there will be a default rendering > IIUC. > This is not quite right. Every visual track in MPEG-4 and QuickTime containers, at least, has a display matrix that determines where it is rendered. The movie's display box is the union of all visual track display boxes, eg. the size and position of a visual track affects the size of its movie. It is certainly *possible* to render an in-band track in the top left corner, and that may be the default in some media authoring software, but it is not a requirement. eric
Received on Thursday, 31 March 2011 14:49:34 UTC