W3C

Timed Text Working Group Teleconference

27 Aug 2015

See also: IRC log

Attendees

Present
pal, nigel, andreas, mike, Courtney
Regrets
thierry, frans
Chair
nigel
Scribe
nigel

Contents


<trackbot> Date: 27 August 2015

<scribe> scribe: nigel

This meeting

nigel: Checks agenda with group. AOB?

group: No other business

Action Items

nigel: All the actions in this section on the agenda have had no work done on them, so we'll move on.

TPAC 2015

nigel: Any issues, agenda requests, queries of any sort?

group: Nothing to discuss right now

HTMLCue proposal progress update

action-415?

<trackbot> action-415 -- Thierry Michel to Send nigel email addresses of htmlcue proposal reviewers -- due 2015-08-27 -- OPEN

<trackbot> http://www.w3.org/AudioVideo/TT/tracker/actions/415

nigel: Thierry did this - I received the addresses from him

close action-415

<trackbot> Closed action-415.

action-416?

<trackbot> action-416 -- Nigel Megitt to Edit proposal and send to htmlcue proposal reviewers as listed by tmichel, following action-415 -- due 2015-08-27 -- OPEN

<trackbot> http://www.w3.org/AudioVideo/TT/tracker/actions/416

nigel: Apologies I haven't managed to do this one yet, hopefully by the middle of next week.
... I don't think there's anything else on this one - but it's worth noting that the dash.js
... project has recently merged an EBU-TT-D implementation that takes this approach, and I
... think had to subvert the VTTCue to do it, but it demonstrates the HTMLCue principle nicely.

mike: The 1.5 release should be next week I believe - the change has been merged.
... It also supports VTT captions.

Unicode liaison

action-417?

<trackbot> action-417 -- Nigel Megitt to Create ticket with unicode for cldr proposal, or add to existing one. -- due 2015-08-27 -- OPEN

<trackbot> http://www.w3.org/AudioVideo/TT/tracker/actions/417

nigel: Again, apologies from me - we decided last week to create a ticket for this and I took
... this action but haven't managed to do it yet.

pal: I'm happy to do this. It's just the act of filing the text of the message we sent before, right?

nigel: Yes, just the same message that we sent to Mark Davis.

pal: I'm happy to do that.

nigel: I wasn't clear if we should add it to the existing ticket or adding a new one.

pal: I may create a new ticket referencing the old one.

nigel: I've updated the action and re-assigned it to Pierre. Thank you Pierre!

pal: No problem!

ATSC liaison

nigel: There's an email here at https://lists.w3.org/Archives/Public/public-tt/2015Aug/0041.html

mike: I don't have too much to add - I proposed a response and nigel proposed some edits.

https://lists.w3.org/Archives/Member/member-tt/2015Aug/0019.html

nigel: There was also a point from glenn saying that just using RGB colours and saying that they are in a different colour space might not be enough.

mike: I don't think that required any changes in the message back to ATSC.

nigel: I agree with that.

mike: Essentially we don't understand why they want to use a new colour model. We identified
... a possible problem of helping presentation processors do the compositing but that's not
... what ATSC asked for.
... I think we've captured the sense of the group.

<scribe> ACTION: nigel Send response back to ATSC as per https://lists.w3.org/Archives/Member/member-tt/2015Aug/0019.html [recorded in http://www.w3.org/2015/08/27-tt-minutes.html#action01]

<trackbot> Created ACTION-418 - Send response back to atsc as per https://lists.w3.org/archives/member/member-tt/2015aug/0019.html [on Nigel Megitt - due 2015-09-03].

@codecs registry

nigel: Again this has been a subject of some discussion over the past week. I believe the main
... point is to see if we can progress this more quickly than TTML2?
... Glenn had proposed putting the @codecs registry in a separate document a while back
... but I think we put it back into TTML2 because the IANA guidelines are to put it in the specification
... that it applies to. If we can separate it out then I don't see why we shouldn't publish separately.

pal: Is there any reason why it can't be a Note?

nigel: Only if it has to have normative status, i.e. it has to be a Recommendation. That would

<pal> http://www.w3.org/TR/media-source/byte-stream-format-registry.html

nigel: incur some process delay whichever way we do it.

<pal> See A.2 at http://www.w3.org/TR/media-source/#bib-MSE-REGISTRY

pal: The MSE registry posted above is an informative reference, which is a prior example we can reference.

nigel: That's helpful - well spotted.

mike: What was the process for that?

pal: None! I think it was consensus of the group to publish it. I remember the exact same
... discussion in the HTML Media Task Force - I think they ended up here. So one thought is we
... could go down that path. I may be able to do some archaeology and dig up the minutes, but
... maybe we should go down those lines since that's what they do in the HTML Media Task Force.

nigel: It looks like this is a lookup table to be helpful rather than defining the MIME subtypes itself.

pal: It does more than simply replicate information present elsewhere.
... It also sets a Generate Timestamps Flag. It has a process for adding entries to the registry.

nigel: I think the draft proposal as it stands now is:
... 1) Create a WG Note describing the registry and the @codecs parameter usage.
... 2) Activate the registry page, either on the wiki or on /TR.
... 3) Also include the syntax for the @codecs parameter and its IANA registration and usage in TTML2.

pal: I think I found the email that closed the discussion...

mike: If there's a history of W3C doing this with WG consensus do we need a Note?

nigel: The Note would be the expression of the WG consensus.

mike: The registry that pierre linked to isn't even a Note - it's just a Document.

<pal> https://lists.w3.org/Archives/Public/public-html-media/2014Jun/0027.html

pal: The head of the thread is:

<pal> https://lists.w3.org/Archives/Public/public-html-media/2014Jun/0013.html

nigel: Seems like this last email suggests it will be okay.

pal: Reading the last email, it seems as though as long as the Registry only references other
... normative documents that seems to be fine. It doesn't have normative references of its own.

mike: It's not intended to be normative - it's just a process and a table of values.

pal: If you read the entire thread they ran into the exact issue that we have, that the W3C doesn't
... have an explicit process for registries or things of that nature. Making it a consensus document
... seems to be a reasonable process.

nigel: Obviously a Note can refer to something non-normative as well as normative.
... Mike, what's the industry context?

mike: It's inadequate to signal TTML as simply the media type, just as it is inadequate to indicate
... video or audio without enough information to deduce if it can be decoded. So all of those
... media streams have a codec value that give more information e.g. profile, bitrate, resolution etc.
... TTML is just the same. I think it's just adequate to signal the profile to which it complies.
... MPEG asked W3C what to do about it and W3C offered to host a registry. MPEG was concerned
... about the long strings that were being used for the profile designators so asked for a more
... concise value to be used in place of the profile URL.

nigel: I'm aware that we don't have staff present, who may have a view, and I'd like people to
... have a chance to review the links that Pierre has posted. So I'd like to hold off this as a
... proposal until next week. Is there anything else to be done in the meantime? Can we draft
... the document? Is it just the existing wiki page?

https://www.w3.org/wiki/TTML/CodecsRegistry

mike: That doesn't contain all the profiles that we know about - there are more to add.

nigel: Is there anything else that would need to be done?

mike: I think so, it's been static for a while. I think it's fair to put people on notice that we propose
... to make this 'live' in the near future.

nigel: Would anyone like to take the action to populate the table with the other values that we are aware of?

mike: I'm happy to do that. We should notify the organisations of what we plan too. I'll try to make them 4 or 5 letters.

nigel: It might be fair to make them all 4 if we can.

mike: If you want them to be meaningful then it will be easier if we allow ourselves to go to 5,
... such as EBUTT, CFFTT, IMSC1 etc.

<scribe> ACTION: mike Add other TTML profiles to the CodecsRegistry wiki page [recorded in http://www.w3.org/2015/08/27-tt-minutes.html#action02]

<trackbot> Created ACTION-419 - Add other ttml profiles to the codecsregistry wiki page [on Mike Dolan - due 2015-09-03].

nigel: Looking at the agenda, I don't think there's anything else we have to discuss, so I'll adjourn the meeting.
... Thanks everyone! [Adjourns meeting]

Summary of Action Items

[NEW] ACTION: mike Add other TTML profiles to the CodecsRegistry wiki page [recorded in http://www.w3.org/2015/08/27-tt-minutes.html#action02]
[NEW] ACTION: nigel Send response back to ATSC as per https://lists.w3.org/Archives/Member/member-tt/2015Aug/0019.html [recorded in http://www.w3.org/2015/08/27-tt-minutes.html#action01]
 
[End of minutes]

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$Date: 2015/08/27 15:01:03 $