Deprecation of smpte:backgroundImage in favor of tt:image

[palemieux]

From Mike Dolan:

Why is #image (from SMPTE namespace) deprecated?

[palemieux]

Deprecation does not mean prohibited, but rather that tt:image should be used instead of smpte:backgroundImage, unless compatibility with IMSC1 processors is desired. tt:image offers significant advantages, such as support for explicit signaling of the media type of the image.

It also satisfies the stated requirement that non-deprecated features of IMSC 1.1 be a subset of TTML2.

[css-meeting-bot]

The Working Group just discussed Deprecation of smpte:backgroundImage in favor of tt:image #259, and agreed to the following resolutions:

• RESOLUTION: Deprecate smpte:backgroundImage in IMSC 1.1 in favour of TTML2 image

The full IRC log of that discussion

<nigel> Topic: Deprecation of smpte:backgroundImage in favor of tt:image #259
<nigel> github: https://github.com//issues/259
<nigel> pal: My proposal is deprecate smpte:backgroundImage in favour of TTML2 image
<nigel> .. In TTML2 image there has to be a mapping specified to smpte:backgroundImage or an
<nigel> .. equivalence.
<nigel> nigel: It can be in IMSC 1.1 can't it?
<nigel> pal: Safe harbor is on SMPTE-TT so if we use image there has to be an equivalence statement.
<nigel> nigel: I need to check my notes on the call I had with SMPTE. The conclusion was certainly
<nigel> .. that we will add a note about the mapping of smpte:backgroundImage but I need to
<nigel> .. check if we need it in TTML2 or IMSC 1.1 or both.
<nigel> glenn: We already agreed in w3c/ttml2#460 to add this note to TTML2
<nigel> RESOLUTION: Deprecate smpte:backgroundImage in IMSC 1.1 in favour of TTML2 image

[palemieux]

See also w3c/ttml2#460 for mapping between smpte:backgroundImage and tt:image.

[palemieux]

@mikedo Does the prose at w3c/ttml2#492, which specifies a mapping between smpte:backgroundImage and tt:image, address your concerns?

[mikedo]

This makes sense given the basic feature addition to TTML2 and the trailing attribution text added in: https://rawgit.com/w3c/ttml2/14678abb328d0bd950a256a29ca82946e04c6703/spec/ttml2.html#embedded-content-vocabulary-image

I recommend committing this only after the above is committed in case there is any discussion on the above.

[palemieux]

Committed at w3c/ttml2@94ecc51