Support live contribution of TTML

[nigelmegitt]

As discussed at TPAC, the requirement is to add sequence handling functionality to align with the EBU-TT Part 3 specification's timing resolution semantics and support the live contribution use case.

[nigelmegitt]

Expected to be discussed further in a joint TTWG/EBU Timed Text face to face meeting on 1st February 2019.

[skynavga]

Please add comments describing why a charter revision is needed.

[nigelmegitt]

In this case it is arguable that the Charter doesn't include the live contribution use case; I agree that it may be possible to do this without a Charter revision, but if we want a new Rec track deliverable document we should be clear about it in the Charter.

[andreastai]

It would be discuss/collect requirements that are not covered by EBU-TT Part 3. This issue may be a good place to collect some of them. It gives a better picture where the gab is and how to start an activity in W3C that adds the new requiements and keeps compatability.

[nigelmegitt]

The obvious requirement not covered by EBU-TT Part 3 is the application of the live stream and document resolution semantics to profiles other than EBU-TT Part 1.

I'm not aware of any other requirement gaps, and would be keen to hear if there are any.

[nigelmegitt]

Discussed in f2f meeting at https://www.w3.org/2019/01/31-tt-minutes.html#item06

Summary:

• Consensus at this stage to proceed with this requirement, as a new Rec track module to be Edited at least by @nigelmegitt.
• Add option for modules to the draft Charter

[nigelmegitt]

Discussed again at https://www.w3.org/2019/02/01-tt-minutes.html#item05 with the conclusion that we will take this work forward for 2019.

[nigelmegitt]

Supporting/interesting reference information from NPO as presented during Friday's face to face meeting joint with EBU: https://www.w3.org/wiki/images/3/31/NPO_slides_2019-02-01-EBU-TT_W3C_joint_meeting.pdf

[nigelmegitt]

After discussion with @plehegar , if EBU is able to submit a proposal then this falls within the existing 2018 Charter scope:

Consider for adoption features from existing formats, such as CEA608 or CEA708, or developed by groups such as SMPTE, DECE and EBU.

and does not require a charter change. I will remove the requires-charter-revision label.