- From: Glenn Adams <glenn@skynav.com>
- Date: Thu, 11 Dec 2014 09:08:42 -0800
- To: Nigel Megitt <nigel.megitt@bbc.co.uk>
- Cc: Timed Text Working Group <public-tt@w3.org>
- Message-ID: <CACQ=j+dw=Fkhee-47+1sbM9L2kbL7TPWxrtQAYAh2jdL9Q0Gyw@mail.gmail.com>
On Thu, Dec 11, 2014 at 1:17 AM, Nigel Megitt <nigel.megitt@bbc.co.uk> wrote: > From: Glenn Adams <glenn@skynav.com> Date: Wednesday, 10 December 2014 > 18:33 > > Now that I've introduced a generic metadata item element, it is better > to satisfy this requirement by simply defining new named metadata items, > representing it as: > > <ttm:item name="sequenceIdentifier">*string*</ttm:item> > > <ttm:item name="sequenceNumber">*positiveInteger*</ttm:item> > > > ttm:item isn't permitted on tt:tt though, which means that there's a > deep parsing requirement to discover this data, so it doesn't satisfy the > requirement. > yes, that's correct, it would require looking into <head/>, but that is analogous to <head> <meta charset="utf-8"/> </head> in HTML5 also, as you might guess, I somewhat modeled <ttm:item name="...">value</ttm:item> on HTML's well used <meta name="..." content="value"/> construct > > Incidentally, if you were to add this concept to isd:isd then the > isd:sequence element would be unnecessary except as a root element in an > XML document, since you could represent a sequence of ISDs using the same > syntax. > an XML document must have a single root element, it cannot have a sequence of elements at root level, so the primary purpose of isd:sequence is to serve that function > I see that isd:sequence and isd:isd do permit content from Metadata.class > whereas tt:tt does not – I'm not sure why there's a difference there, in > principle anyway. > since isd:sequence (and isd:isd) can potentially have document level metadata, i.e., derived from <head><metadata>...</metadata></head>, and since I didn't specify a head element in ISD syntax, I had to put them somewhere, so I put them at first position among children > > > > On Wed, Dec 10, 2014 at 9:56 AM, Timed Text Working Group Issue Tracker < > sysbot+tracker@w3.org> wrote: > >> ISSUE-358 (Sequence support): Add identifier support for related ordered >> sequences of documents [TTML2] >> >> http://www.w3.org/AudioVideo/TT/tracker/issues/358 >> >> Raised by: Nigel Megitt >> On product: TTML2 >> >> In an authoring environment that creates an ordered sequence of TTML >> documents that collectively form some kind of coherent representation >> collectively, such as a sequence of documents created 'live', it is useful >> to be able to identify at the root level, i.e. with minimal parsing >> requirements, that: >> >> 1. A collection of documents belongs to the same sequence and >> 2. The relative ordering of a document within the sequence. >> >> This also relates to Change Proposal 25 and Issue-288, and the proposal >> made in the November TPAC meeting. >> >> Modified proposal now includes a sequence number: >> >> Metadata attribute ttm:sequenceIdentifier >> Considered significant on tt:tt only. >> Optional attribute. >> Type xs:string >> Description: The ttm:sequenceIdentifier metadata attribute can be used to >> distinguish between sequences of documents where the documents within a >> sequence are related to each other but there is not necessarily any >> relationship between different sequences. >> >> Metadata attribute ttm:sequenceNumber >> Considered significant on tt:tt only. >> Optional attribute. >> Type xs:positiveInteger >> Description: The ttm:sequenceNumber metadata attribute can be used to >> sort documents with the same sequenceIdentifier into a defined order. Two >> documents with the same sequenceIdentifier SHOULD NOT have the same >> sequenceNumber, if sequenceNumber is used. >> >> >> >> Note that this proposal mirrors work happening in EBU but is my proposal >> and not an EBU proposal, for the avoidance of doubt. >> >> >> >> >
Received on Thursday, 11 December 2014 17:09:33 UTC