- From: Timed Text Working Group Issue Tracker <sysbot+tracker@w3.org>
- Date: Thu, 11 Jul 2013 16:16:57 +0000
- To: public-tt@w3.org
ISSUE-261: signaling docoument profile conformance is separate from decoder presentation requirements [TTML.next] http://www.w3.org/AudioVideo/TT/tracker/issues/261 Raised by: Mike Dolan On product: TTML.next The profile element and attribute currently signal a feature set that a decoder must implement in order to reasonably present the document. Although it also hints at what features the document instance may include, it does not signal document instance conformance today. There is currently no mechanism to signal what profile a document instance conforms to (e.g. sdp-us). It is desirable to add this capability to TTML. However, simply adding this semantic to the existing profile element and attribute overly constrains the existing (decoder) and desired (document) semantics. It is unreasonable to require that the single element and attribute simultaneously signal both. For example, the fact that a document instance conforms to dfxp-full does and should not automatically infer that an sdp-us decoder could not properly present it. That is instance dependent. This situation is aggravated when multiple profiles are involved. Some means must be defined to separately signal these different semantics. For example, we could create a new element and attribute - <ContentProfile> and contentProfile.
Received on Thursday, 11 July 2013 16:16:58 UTC