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1,301 bytes added, 04:32, 20 March 2010
started on display hints
* "text/tickertext"
* "text/lyrics"
* "text/activeregion"
* "text/metadata"
* "text/annotation"
* "text/transcript"
* "text/linguistic"
* "text/chapters"
Video tracks:
Notice how we are re-using the Content-type approach of specifying the main semantic type of the track first. This is necessary, since mime types don't always provide the right main content type (e.g. application/kate is semantically a text format).
There may also be parameters to describe the roles better, such as "video/alternate;angle=nw"
=== Display-hint ===
Media players that do not get informed about how a content author intends a media file to be displayed have no change to display the content "correctly". This is why the Display-hint message header field allows providing of hints on how a certain track should be displayed. A media player can of course decide to ignore these hints.
Example hints are:
* pip(x,y,w,h) on a video track - picture-in-picture display in relation to the "main" video track with x,y providing the origin of the top left corner of the PIP video and w,h the width and height
* mask(x,y,w,h,img) on a video track - use the image given at img url (?) as a video mask to allow the video to appear in shapes other than rectangular. The masking image should be a black shape on a white background. The image is placed at offset x,y and scaled to width and height w and h. Pixels under the white background are made transparent and only pixels under the black shape are retained.
* overlay(transparency) on a video track -
* alpha(trackref) on a video track -
This track order is simply to have a means to address tracks through an index. It has no influence on what should be displayed on top of which other track.
== Track dependencies ===

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