[imsc] span elements are included in NBG(R_i) (#571)

palemieux has just created a new issue for https://github.com/w3c/imsc:

== span elements are included in NBG(R_i) ==
The quantity NBG(R<sub>i</sub>) counts the number of `tts:backgroundColor` attributes specified  `span` elements. 

The application of background on a span element is however more akin to the application of a color or font style.

`span` should be excluded from NBG(R<sub>i</sub>) computation, and `tts:backgroundColor` should instead be included in the list of glyph properties at https://www.w3.org/TR/ttml-imsc1.1/#paint-text.

Please view or discuss this issue at https://github.com/w3c/imsc/issues/571 using your GitHub account


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Received on Wednesday, 2 June 2021 18:45:14 UTC