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[imsc] consider removing recommendations that do not appear to address a technical problem

From: Michael A Dolan via GitHub <sysbot+gh@w3.org>
Date: Tue, 06 Feb 2018 23:48:09 +0000
To: public-tt@w3.org
Message-ID: <issues.opened-294954921-1517960888-sysbot+gh@w3.org>
mikedo has just created a new issue for https://github.com/w3c/imsc:

== consider removing recommendations that do not appear to address a technical problem ==
I've run across a couple of "should" recommendations for things that do not appear to solve any problem, and in some cases discourage useful practices. And, validators tend to flag warnings if the recommendation is not followed, even though it is necessary.  Examples:

6.11 "If the Document Instance includes any length value that uses the c expression, ttp:cellResolution SHOULD be present on the tt element." Why? there is a well-defined initial value. If the author wishes to use that, what is the purpose of adding this attribute set what is already set?

6.11 "All time expressions within a Document Instance SHOULD use the same syntax, either clock-time or offset-time." Why?  Since decoders are required to handle both concurrently, what does this solve. It takes away the ability to mix setting "sync" points with clock-time and using offset-time for blocks (div) that can be reused in multiple places on the timeline.

I did not do an exhaustive analysis.

I believe removing these provisions would cause no harm. 1.0 documents would remain conformant, and decoders should not care since they already have to operate without the recommendations.

Please view or discuss this issue at https://github.com/w3c/imsc/issues/329 using your GitHub account
Received on Tuesday, 6 February 2018 23:48:16 UTC

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