W3C home > Mailing lists > Public > public-tt@w3.org > January 2013

Re: TTML and aspect ratio

From: Glenn Adams <glenn@skynav.com>
Date: Wed, 30 Jan 2013 10:58:36 -0700
Message-ID: <CACQ=j+dZCYJr6eGr6GX7kL-P6+wkwErxtM+5cD_SK2y03Ho9Zw@mail.gmail.com>
To: David Ronca <dronca@netflix.com>
Cc: "public-tt@w3.org" <public-tt@w3.org>
On Wed, Jan 30, 2013 at 10:31 AM, David Ronca <dronca@netflix.com> wrote:

> > That's not at all obvious to me. Firstly, why would this be different
> that <tt tts:extent>?
> <tt tts:extent> specifies the display area.  A client may ignore the pixel
> address and only use the computed DAR, but that would be a client-specific
> behavior that is undefined in the spec.

If the extent is specified, then it cannot be ignored by a compliant
client. A compliant client is obligated to respect that extent

It is sounding to me like you want to avoid specifying root container
extent at all, but have a way to automatically determine it in the client
based on an a specified aspect ratio and possibly a safe area
specification, is that correct?

If so, would other length specifications always use non-pixel metrics or
percentages? e.g., to specify non-root region origin and extent, use cells
or percentages, but not pixels?
Received on Wednesday, 30 January 2013 17:59:24 UTC

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