Re: Re: TTML and aspect ratio

>The implementer of the client provides it. The implementer might ask the
>user, or the system platform might define. Or the TTML client might be
>embedded in a larger context (e.g., an HTML5 browser) that provides its own
>mechanism for defining where to present captions.

 A proprietary model will not work.  We need a method to define a consistent layout for *any* well behaved client.  Consider two scenarios:  1) we implement a client to present the W3C-tt, 2) we pass the W3C-tt to a client that will do the presentation (i.e. game console, etc.).  For both of these scenarios, the client *must* present the captions in a proper and consistent way.  This is our use case, and it does not work if TT presentation is based on an undefined "external authoring context".  

We believe that our use case can be accomplished as follows:
1) Cell or percentage positioning
2) default <tt tts:extent>
3) The addition of root container aspect ratio (along with a default behavior for centering the root container in the video window rule).

Received on Thursday, 31 January 2013 14:46:06 UTC