Nigel Megitt

I think this is a misunderstanding of this part of the spec. My understanding (which I would like @tairt to confirm) is that this text in §3.1.4.2 of Tech3350 v1.1...

In other words my understanding is that there is no further semantic or syntactic validation requirement associated with that spec text.

OK but that is not a validation requirement associated with that piece of spec text, but with the parts of the spec that allow those style attributes on the region...

Specifically the bit that you do not need to check if I understand correctly is to see if any style attributes are defined on `style` elements that are also defined...

Well yes, as per TTML1, in general if I remember correctly the rule is to apply more locally specified styles in favour of less locally specified ones, so: ``` xml...

That's still more elegant than comments, even if the counting semantics aren't ideal.

Is this a duplicate of #269 ?

There are two things going on here. Firstly the request for the segment that 570 occupies comes before it is available, so it is completely reasonable not to output it,...

This does not appear to be essential for R2 - any views?

This is important but not urgent for R2, bumping to R3.