ISSUE-332: #cellResolution support

#cellResolution support

#cellResolution support

State:

CLOSED

Product:

TTML IMSC 1.0

Raised by:

Frans de Jong

Opened on:

2014-08-07

Description:

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Request
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Chapter 4.8 (Common Constraints -> Features)

The part:

"#cellResolution SHALL NOT be used."

should be deleted.

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Reasoning
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IMSC currently does not allow the use of the feature #cellResolution
https://dvcs.w3.org/hg/ttml/raw-file/tip/ttml-ww-profiles/ttml-ww-profiles.html#features

It is not sufficient that an IMSC processor processes the EBU-TT-D document but ignores cellResolution values. Indirectly the cellResolution defines the fontSize. IMSC calculates the fontSize in percentages with an implicit cellResolution (with the TTML initial value, "32 15"). EBU-TT-D documents (example here: http://tech.ebu.ch/docs/ebu-tt/ebu-tt-d-imsc-compliance-example.xml ) will renderin a different font-size and therefore intended line breaks cannot be guaranteed. In this use case this is not acceptable for the broadcaster.

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General use case
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A german broadcaster uses an EBU-TT-D document (https://tech.ebu.ch/docs/ebu-tt/ebu-tt-d-imsc-compliance-example.xml) for HbbTV subtitles and for their catch up tv - portal for PC. Both the HbbTV application (or in the future the HbbTV 2.0 compliant device) and the player of the EBU-TT-D portal support EBU-TT-D. Now the broadcaster licences the same AV content together with the subtitles to a commercial on-demand Internet streaming media provider. The provider distributes its content to a client which is conformant to IMSC 1.0 (IMSC 1.0 Text - http://www.w3.org/ns/ttml/profile/imsc1/text). Conformance to EBU-TT-D of this player is not documented.

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Requirement
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The broadcaster demands from the provider that the subtitles will be displayed as specified in the EBU-TT-D file. The provider will distribute the EBU-TT-D file as it is provided and will not convert the EBU-TT-D file.

Related Actions Items:

No related actions

Related emails:

1. {agenda} TTWG Meeting 25/9/2014 (from nigel.megitt@bbc.co.uk on 2014-09-24)
2. Re: ISSUE-332 (-): #cellResolution support [TTML IMSC 1.0] (from pal@sandflow.com on 2014-09-23)
3. Re: {minutes} TTWG Meeting 11/9/2014 (from silviapfeiffer1@gmail.com on 2014-09-13)
4. Re: IMSC 1 re: ISSUE-332, ISSUE-342 and ISSUE-339 (from nigel.megitt@bbc.co.uk on 2014-09-12)
5. Re: {minutes} TTWG Meeting 11/9/2014 (from nigel.megitt@bbc.co.uk on 2014-09-12)
6. Re: {minutes} TTWG Meeting 11/9/2014 (from silviapfeiffer1@gmail.com on 2014-09-12)
7. Re: {minutes} TTWG Meeting 11/9/2014 (from silviapfeiffer1@gmail.com on 2014-09-12)
8. Re: {minutes} TTWG Meeting 11/9/2014 (from ckennedy@apple.com on 2014-09-11)
9. Re: IMSC 1 re: ISSUE-332, ISSUE-342 and ISSUE-339 (from John.Birch@screensystems.tv on 2014-09-11)
10. Re: IMSC 1 re: ISSUE-332, ISSUE-342 and ISSUE-339 (from pal@sandflow.com on 2014-09-11)
11. Re: IMSC 1 re: ISSUE-332, ISSUE-342 and ISSUE-339 (from nigel.megitt@bbc.co.uk on 2014-09-11)
12. Re: IMSC 1 re: ISSUE-332, ISSUE-342 and ISSUE-339 (from pal@sandflow.com on 2014-09-11)
13. {minutes} TTWG Meeting 11/9/2014 (from nigel.megitt@bbc.co.uk on 2014-09-11)
14. Re: IMSC 1 re: ISSUE-332, ISSUE-342 and ISSUE-339 (from John.Birch@screensystems.tv on 2014-09-11)
15. IMSC 1 re: ISSUE-332, ISSUE-342 and ISSUE-339 (from pal@sandflow.com on 2014-09-10)
16. Re: {agenda} TTWG Meeting 11/9/2014 (from glenn@skynav.com on 2014-09-10)
17. {agenda} TTWG Meeting 11/9/2014 (from nigel.megitt@bbc.co.uk on 2014-09-10)
18. {agenda} TTWG Meeting 4/9/2014 (from nigel.megitt@bbc.co.uk on 2014-09-03)
19. {agenda} TTWG Meeting 21/8/2014 (from nigel.megitt@bbc.co.uk on 2014-08-20)
20. Re: New Change Proposal 28 on IMSC 1: Profile refactoring (from nigel.megitt@bbc.co.uk on 2014-08-14)
21. Re: New Change Proposal 28 on IMSC 1: Profile refactoring (from pal@sandflow.com on 2014-08-14)
22. {agenda} TTWG Meeting 14/8/2014 (from nigel.megitt@bbc.co.uk on 2014-08-13)
23. New Change Proposal 28 on IMSC 1: Profile refactoring (from nigel.megitt@bbc.co.uk on 2014-08-08)
24. Re: {minutes} TTWG Meeting 7/8/2014 (from glenn@skynav.com on 2014-08-07)
25. {minutes} TTWG Meeting 7/8/2014 (from nigel.megitt@bbc.co.uk on 2014-08-07)
26. ISSUE-332 (-): #cellResolution support [TTML IMSC 1.0] (from sysbot+tracker@w3.org on 2014-08-07)

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