search

ebu / ebu-tt-live-toolkit

Toolkit for supporting the EBU-TT Live specification
http://ebu.github.io/ebu-tt-live-toolkit/
BSD 3-Clause "New" or "Revised" License
25 stars 10 forks source link

[EBUTTD] Style and region linking for subset #171

Closed kozmaz87 closed 7 years ago

kozmaz87 commented 8 years ago

Relevant conversation:

nigel [4:48 PM]
It’s a mapping exercise. TT3 doc 5 had div region="r1" and doc6 has the same but the region definitions are different.

[4:49]
Then when you create the region corresponding to the content from doc 5 you create a map entry “I need a region for doc 5 r1”, use an ID generator to give you a new unique id value U1, and record the mapping from doc 5 r1 to U1. Then when you get to doc 6 r1 you find you don’t have an entry in the map, so you make one, and get U2 for it.

[4:50]
The later optimisation is to identify identical regions and combine them.

[4:50]
the map could be done with clever IDs but it’s not lovely. e.g. create a new unique id by concatenating sequenceId + sequenceNum + xml:id

kozmaz87 commented 8 years ago

NOTE: contents of tt/head/layout are optional and layout itself is optional as well. Maybe on purpose maybe just bit too loose. unsure.

nigelmegitt commented 8 years ago

Not sure what impact this note has? It's deliberate in the EBU-TT Part 3 spec to leave them optional, but it's equally deliberate in EBU-TT-D to require them to be present except in the "empty document".