{minutes} TTWG/EBU TT joint face to face meeting 2019-02-01

Thanks all for joining today's face to face TTWG meeting jointly with the EBU Timed Text group. Minutes can be found in html format at https://www.w3.org/2019/02/01-tt-minutes.html


In text format:


   [1]W3C

      [1] http://www.w3.org/


                Timed Text Working Group Teleconference

01 Feb 2019

   [2]Agenda

      [2] https://www.w3.org/wiki/TimedText/F2F-jan-2019#Day_2_.2808:30-13:30.29


   See also: [3]IRC log

      [3] https://www.w3.org/2019/02/01-tt-irc


Attendees

   Present
          Andreas, Pierre, Thierry, Glenn, Matt, Marco_Slik,
          Frans, Gary

   Regrets

   Chair
          Nigel

   Scribe
          nigel

Contents

     * [4]Topics
         1. [5]Introductions
         2. [6]This meeting
         3. [7]EBU Extensions to TTML
         4. [8]Overview of EBU standards
         5. [9]Live subtitle contribution
         6. [10]EBU and W3C collaboration
     * [11]Summary of Action Items
     * [12]Summary of Resolutions
     __________________________________________________________

   <scribe> scribe: nigel

Introductions

   Andreas: Welcome everyone to this joint meeting of the W3C
   Timed Text Working Group and EBU Timed
   ... Text groups.
   ... I chair the EBU group, and Nigel is a chair of both of the
   groups.

   Nigel: Do we all know each other?

   Andreas: We mostly met yesterday but introductions could be
   useful for some people.

   Marco: I'm Marco Slik, an R&D engineer at NPO in the
   Netherlands involved in the very broad spectrum
   ... of playout distribution and access services, I joined the
   EBU group a few years ago.

   Gary: Hi, I work at Brightcove, we do online video with
   video.js and the web player and I focus on WebVTT

   Thierry: Thierry Michel, W3C team contact for this WG

   Nigel: Just an admin statement for me, which is that as a W3C
   WG meeting any IPR contributed here
   ... needs to be cleared. TTWG members have already made this
   commitment, if any non-TTWG members
   ... contribute any substantive material that ends up in a W3C
   Recommendation track document then as
   ... Chair I will need to get a similar commitment from the
   contributor.
   ... That's the formality over, in terms of IPR!
   ... Can I check everyone is aware of IRC and the minuting of
   this meeting?

   Andreas: Yes, I will send the links around too.

   Nigel: Just to let everyone know that this meeting will be
   scribed on IRC and that the log will be
   ... turned into public-visible minutes after the meeting. If
   you do not wish something to be minuted
   ... please tell me before you say it!

This meeting

   Andreas: One of the reasons we meet together today is the
   shared interest in live TTML.
   ... We had a discussion at the TPAC meeting in Lyon a few
   months ago and also some other discussions
   ... in the EBU group about this.
   ... There was a discussion of the submission of EBU-TT Live to
   W3C. At TPAC we decided we needed
   ... more information about the plans of the groups regarding
   live and standards activities.
   ... So we thought this meeting would be a perfect opportunity
   to discuss this.
   ... The main part will be dedicated to this topic.
   ... By introduction we have some example from operation, Nigel
   from BBC, and the open source
   ... activity of the EBU-TT Live Interoperability Toolkit.
   ... Matt from Red Bee, and Marco from NPO and I will bring in
   requirements from some German
   ... broadcasters.
   ... After that we will look at the live standards activity.
   ... Also as we're here today we can widen the scope a little
   bit.
   ... I talked to people before. My interest would be to check
   how much we can bring TTWG and EBU TT
   ... activities together and doing more work in W3C.
   ... [missed a bit]
   ... We have concrete examples of multiRowAlign and linePadding.
   ... The order is not fixed yet, we have a list of topics on the
   wiki page.
   ... We can discuss where to start.

   Nigel: Thanks for that, as you have said we have a list of
   topics on the wiki page.
   ... Looking at the schedule, what should we look at first?

   Andreas: Let's begin concrete with EBU extensions and then dive
   into live.
   ... Then come back to cooperation and collaboration of the
   groups at the end of the meeting.

EBU Extensions to TTML

   Andreas: Some information I shared

   -> [pointer to Andreas summary mail] Andreas's summary text

   Andreas: The main question is if the two vocabulary items
   ebutts:multiRowAlign and ebutts:linePadding
   ... If it makes standards work of W3C easier we would be able
   to allow them to be maintained in the TTWG.
   ... If there's interest in W3C group to do this.
   ... Otherwise we can keep it in the EBU TT group scope.
   ... I sent an email to the EBU reflector making a proposal, and
   have had no objections to that proposal.
   ... From whatever date, multiRowAlign and linePadding are
   maintained and at the end controlled no longer
   ... by EBU but by W3C. EBU will not make any changes to them.
   ... If there is another EBU spec then it can reference any
   updated definition in a W3C spec.
   ... This allows easier maintenance and adoption of bug fixes
   found during W3C activities.
   ... The general idea is to update the items for clarification
   and bug fixing.
   ... If completely new requirements come up that are not
   satisfied by them then it may be better to add
   ... two completely new items in the TTML namespace. If for some
   reasons semantics change then it is in
   ... the interests of the EBU group that they are backward
   compatible with the existing EBU definitions.
   ... If W3C has control then they maintain it and it is their
   decision process how to deal with updates.
   ... We currently have at least 4 members who are in both groups
   then I do not see any conflict.

   Matt: Is there any precedence for this?

   Frans: I'm not aware of this exact case.

   Glenn: When you say hand over control are you assuming a
   namespace change?

   Andreas: No

   Glenn: The proposal is a syntactic transfer but cede control to
   the W3C of that subset of the EBU owned
   ... namespace?

   Andreas: Yes
   ... Pierre as editor of IMSC, the question is if there is any
   benefit. I think it is clear it would be maintained
   ... in IMSC scope.

   Pierre: There's always a benefit in having a single forum to
   address issues.

   Glenn: If the formal definition moves to IMSC, would it be
   feasible to define, say in TTML3, two new
   ... attributes of the same name but in the TTML namespace?

   Pierre: To me that's a separate issue.

   Glenn: Well they're both in W3C control

   Pierre: That's true today

   Matt: Would they be equivalents?

   Glenn: I've objected to including foreign namespaces in TTML in
   the past.
   ... That's not true for IMSC which is a profile that adds
   vocabulary from other places like EBU-TT.
   ... That was completely appropriate in IMSC, but it has never
   been the case that TTML refers to foreign
   ... namespaces. If we do this then we should have a plan or
   intent to bring them into the TTML style
   ... namespace and define them equivalently.

   Pierre: That's orthogonal, we could do that today.

   Glenn: If you think that's possible, then that's okay.

   Andreas: Your proposal is to duplicate semantics but give it a
   different name or namespace?

   Glenn: 1. Move formal definition into IMSC, same namespace,
   words etc so it is consistently defined.
   ... 2. Define the same names and semantics in a TTML namespace.
   At that point the IMSC spec could be
   ... updated to refer to the TTML namespace semantics if it
   wants to and also say it is available in the EBU
   ... namespace.

   Andreas: This has been discussed in the past and EBU has said
   that is not the intent to duplicate existing
   ... vocabulary items, and that duplication makes no sense.
   Personally I think that is the best strategy.
   ... We use the EBU vocabulary items because they are
   established, implemented and we don't want to
   ... make other implementations have to change to a new
   vocabulary with no need.
   ... This is formally not needed but it goes together. If the
   overall intent is to duplicate the EBU namespace
   ... items without adding new functionality that would not
   really justify bringing over the control of the
   ... EBU namespace items. We had this discussion in the past and
   the position has not changed.

   Glenn: We have to recognise that IMSC and TTML are different
   and have different conventions.
   ... We have followed different restrictions. As a primary
   language definition it does not reference any
   ... foreign namespaces, just the core XML namespaces and those
   defined in TTML itself.
   ... Other than this potentially we have never discussed a
   proposal or accepted one to refer to foreign namespace.

   Pierre: I don't see why we need it.
   ... W3C could decide today to create a duplicate attribute.
   We've had that discussion. I don't see what is different.

   Glenn: Bringing them in to IMSC will not satisfy requirements
   for TTML that are not IMSC users.
   ... Everything is in the TT namespaces.

   Pierre: We can have that discussion (again).

   Glenn: I have no objection to making use of the EBU technology.
   It is great, proven, deployed, and I don't
   ... want to seem like I'm denigrating EBU in this regard.
   ... As Editor of the primary core language definition I have to
   stand by certain principles of language
   ... consistency and this is one I'm going to insist on.

   Andreas: Possibly it is best to follow Pierre's proposal and
   concentrate on what is on the table.
   ... This would be to hand over control of the items
   multiRowAlign and linePadding only into W3C for
   ... adoption by IMSC and nothing else.
   ... What is the opinion of the other members present?

   Matt: I think it seems sensible. The one question for me is the
   overall strategy and context?

   Frans: Pragmatism

   Matt: It doesn't make sense to have multiple definitions of the
   same thing and then the community would
   ... need to do the same work twice.
   ... We would like to contribute to the biggest circle in the
   venn diagram unless there's a proposal that is
   ... hyper-specific. We would like to break down the notion that
   captions and subtitles are different from
   ... country to country because in my experience they are not.
   Interoperability is the goal.

   Frans: I totally agree, this makes sense and we should be
   pragmatic not thinking about not invented here
   ... concerns.

   Andreas: I see nodding from Marco, no objection from W3C side.
   ... I will share the proposal from the EBU with the Timed Text
   group.

   Pierre: I think a liaison is needed, and an issue on IMSC to
   adopt in the next version.

   Nigel: I'm not sure if a liaison is needed.

   Pierre: For future generations a standalone piece of paper that
   explains what happened would be useful.

   Andreas: I can make a proposal offline and check it with both
   groups to go forward.

   Nigel: That is okay for me too.

Overview of EBU standards

   Andreas: [shows list of EBU specs]
   ... EBU-TT Part 1 v1.2, the base of every standard we
   published, intended originally for exchange and archive,
   ... as the successor to STL.
   ... Not in TTML2: linePadding, multiRowAlign
   ... Not in IMSC: smpte, clock timebase, markerMode, clockMode,
   cell length metric except for linePadding
   ... EBu-TT-D, same scope as IMSC, a subset of IMSC. Includes
   multiRowAlign and linePadding.
   ... EBU-TT Live, subtitle contribution over IP. As well as
   multiRowAlign and linePadding, there are four
   ... attributes not in TTML2 or in IMSC, sequenceIdentifier,
   sequenceNumber, authorsGroupIdentifier,
   ... authorsGroupControlToken.
   ... EBU-TT Part M is definition of metadata elements, no
   compatibility issue because TTML and IMSC allow
   ... adding metadata.
   ... Also we have some complementary documents.
   ... A recommendation how to map EBU STL to EBU-TT Part 1.
   ... A recommendation for carrying EBU-TT-D in ISO BMFF.
   ... A carriage spec for carrying EBU-TT Live over WebSocket.
   ...
   ... A question I have is for not just EBU-TT Live, but also
   part 1 and EBU-TT-D how they could converge
   ... with the TTML specs. Later we have an EBU group meeting,
   this will be one part of the discussion there.
   ... Looking at the minimal part that is not inside IMSC or TTML
   I see some option really to possibly
   ... make use of some W3C specs to satisfy the use case we
   originally thought of with part 1 and Live.
   ... EBU-TT-D is already solved by IMSC, EBU-TT-D is just more
   restricted.

   Glenn: The idea is to identify areas of difference as you have
   summarised, and then find ways to...
   ... I guess I'm not clear on the next step - update the EBU
   specs? Or some action on W3C side?

   Andreas: The background is the situation that if you go to the
   industry and ask about information about
   ... TTML they say there are so many profiles they don't know
   which ones to support. They don't implement
   ... a complete set. That's not a good situation, so I think it
   would help to limit the set of standards that
   ... needs to be implemented, and I really like simple solutions
   so in my simplified view, for example for
   ... part 1 we could say for production and exchange, just use
   IMSC, but then check if everything in IMSC
   ... now satisfies this use case, and if not, make an addition
   or some other change so that, out there, where
   ... we need implementation, people know they just need to
   implement IMSC.

   Glenn: Thinking aloud, I'm wondering if part of the problem
   with all these profiles is that very few clients
   ... if any actually do the profile processing that is defined
   by TTML in the sense that it actually verifies
   ... if the profile asks for features to be supported and acts
   accordingly if they are not.
   ... I felt always bad about the history of the EBU's adoption
   of TTML when it ruled out use of the profile
   ... system which I thought then and still think is a mistake
   because it removes the ability of the client to
   ... refer to the author defined profile information. I'm not
   suggesting anything, but it may be that the fact
   ... that very few clients use the profile is part of the
   problem.

   Andreas: Try to look forward not backward.

   Glenn: I agree.

   Nigel: Chicken and egg problem - if profile adoption is not
   there then it is hard to specify it, and TTML
   ... implementation is already big enough without including
   profiles.

   Andreas: Question for Pierre, do you see a path to adding
   EBU-TT Part 1 syntax into IMSC if there's a gap?

   Pierre: We can look at it, it is not worth creating another
   flavour/layer/profile but if they are useful
   ... in production only but not distribution then maybe there is
   genuinely a need for another flavour.

   Frans: There has been little drive to change the production
   side, more the distribution side.
   ... So EBU-TT has not been well adopted.

   Matt: We've made a lot of EBU-TT output, everything for BBC
   since 2014. We probably could derive some
   ... useful stats on the number of EBU-TT documents.
   ... Ofcom has recently published a statement about the
   extension of accessibility regulation to online
   ... video platforms, which included something about standards
   support. There was an attempt to try to
   ... persuade the regulator to add guidance or stronger to
   direct content providers to use particular formats.
   ... We have one client for whom we make 13 or 14 different
   variants of the same data. That's driven by
   ... probably no good reason, but the proliferation has caused
   fogginess. Anything we can do to reduce
   ... that will be very valid and valuable. If you read that
   statement, [missed a bit] those are not small
   ... amounts of money, having one format that could be
   propagated to every platform would be very
   ... useful.

   Andreas: Useful comments. From my experience IMSC for example
   [missed a bit]
   ... but the value of having one format overweights possibly the
   extra work for features that may not be
   ... needed. Most of the things we leave out are not really a
   problem in the implementation. It is more the
   ... parts we brought in, with multiRowAlign, lineGap etc are
   the tricky parts.
   ... To actively give the message that you need to implement
   full IMSC coming from different standards
   ... organisations would definitely help I think. One of the
   main questions we can look at already for
   ... IMSC is timecode. We had discussions with lots of people,
   lots of stakeholders are not yet ready to
   ... go away from timecode.

   Pierre: And a lot of them use it badly. We really have to
   understand the use cases extremely well.
   ... In the modern world timecode will not work 99.99% of the
   time with component based media.

   Frans: I can only agree it must be use case driven.
   ... That's the most important for production.

   Marco: When you want to transition you have to support some
   things... [missed a bit]

   Pierre: It will not work with online media.

   Marco: I will not manage to get away from smpte timecode in 3
   years, but we could maybe start the timecode
   ... clock at zero for example.

   Pierre: I don't think saying timecode can not or must be used
   is the answer, it's a lot more nuanced.

   Andreas: I do not think we can say we see a better future and
   will not help you now.
   ... For German broadcasters we need an incentive to change from
   STL.
   ... We thought we did that with EBU-TT but they did not use it.

   Frans: When we started the work the premise was that STL can
   not do the things we want but in
   ... production people have not hit that wall yet.

   Matt: Yes, we have not hit that inflection point. We're getting
   more foreign languages, like Mandarin.
   ... We can't do live captioning in Mandarin, in 608 or
   Teletext, but we need an answer before people
   ... invent something that won't work.

   Glenn: A character coding issue?

   Matt: Yes but the broadcast standards don't support those
   characters.

   Pierre: Contribution of HD single language content is a solved
   problem. We're not competing with ATSC or 608.
   ... We're talking about worldwide online distribution of
   content.

   Matt: Precisely. We're working with an online entity that has
   no SDI platform.

   Andreas: That's a good start into the discussion, I propose we
   move over.

   Pierre: On that topic, since we're all together, if we are
   serious about trying to rationalise this it would
   ... probably be a good idea to set aside a day at a workshop to
   really get to the bottom of it, and get
   ... people to tell us what they are doing and want to do
   otherwise we will make a wrong decision.

   Frans: We tried to do this a number of years ago for EBU-TT
   Live.

   Pierre: For instance EBU-TT Part 1, who are the target users?

   Andreas: Everyone who uses STL.

   Matt: I can collate data from most UK broadcasters.

   Frans: I do think there is point to verifying proposed pain
   points with users.

   Andreas: From the experience of the live workshop it was a bit
   chaotic and was hard to bring together.
   ... It was good at that time, but as you say everyone goes to
   their domain and community and we come
   ... back maybe in the same kind of circle.

   Pierre: Next opportunity is maybe IBC.
   ... It would be awesome to end up with a single format across
   the entire chain, not for old applications.

   Andreas: yes and if we are committed I'm sure we will get
   others onboard.

   Matt: Clients ask us how to give flesh to the ecosystem

   Frans: We need to give a roadmap

   Matt: And state the benefits.

   Nigel: That Live workshop was in the same room as this meeting
   in 2012, and one of the reason it was
   ... chaotic was that people wanted to address not just the
   workflow we had in scope but at least one step
   ... further, like speech to text engines.

   Frans: I agree, we need to focus on the use cases.

Live subtitle contribution

   nigel: [describes EBU-TT Live and the Live Interoperability
   Toolkit] - Frans took notes.

   <inserted> BBC subtiltes 100%, includes all live programmes.

   <inserted> Stateful Teletext based (legacy) technology is used
   for this.

   <inserted> Does NOT support future requirements, such as live
   streaming of bespoke events, cloud encoding, etc.

   <inserted> When studying the standards supporitng this
   authoring-to-encoding part of the workflow.

   <inserted> EBU-TT was the obvious choice (the BBC was already
   producing in EBU-TT).

   <inserted> EBU-TT-Live (Tech 3370) specifies how you can send a
   stream of text chunks to facilitate this scenario; with 0 or 1
   documents 'active' at any time.

   <inserted> The EBU-TT-Live Toolkit validated the spec and helps
   implement it: [13]https://github.com/ebu/ebu-tt-live-toolkit


     [13] https://github.com/ebu/ebu-tt-live-toolkit


   <inserted> Timed changes do not have to be explicit ('just send
   a new document') as was demoed in the SwissTXT demonstration at
   EBU PTS 2019 for example.

   <inserted> SMPTE timecode is not allowed (as you cannot do
   match on it).

   <inserted> Carriage using web sockets has been defined.

   <inserted> EBU-TT-Live / TTML carriage in RTP for use in SMPTE
   2110 ("IP replacement of SDI") is being worked on; BBC has
   submitted an RFC for TTML carriage in RTP.

   Matt: Background to fit into that.
   ... [shows slides]
   ... We're a subtitle vendor, and a few years ago wanted to
   replace our live captioning platform. We were
   ... surprised at the lack of forwards thinking in the market. I
   was in this group already at that point and
   ... could see that the world would change and Teletext would
   not work.
   ... We built our own java based captioning tool called Subito.
   ... Effectively internally it makes TTML.
   ... Can output Teletext, Nufor, 608, Cavena, EBU-TT Live, and
   can do those simultaneously, applying
   ... the constraints in real time.
   ... We did our first presentation at PTS 2 years ago, and did
   some work using the LIT. We had a basic but
   ... brittle proof of concept. More recently using for our
   customers.
   ... Development challenges, managing pre-conceptions of HTML
   and XML ignoring good EBU documentation
   ... ignoring format details because of lack of understanding of
   the use case, so deviating from the spec.
   ... Partly caused by lack of reference examples and material.
   ... Bad habits like using line breaks for positioning.
   ... Ignoring test materials that are free like the Interop
   Toolkit.
   ... Challenges about reformatting, we focused on conveying the
   intent of the captioner to the stream.
   ... But how to cope if presentation format is a different
   aspect or applies other constraints?
   ... In the implementation side we didn't think enough about
   that. No practical constraints, but need to
   ... avoid developers making inappropriate solutions.
   ... We created a multichannel Distribution Node. Originally we
   required consumers to connect in, what we now
   ... have is scalable and supports multiple destinations.
   ... Testing is difficult, need a 24/7 delivery destination.
   ... Security: not an issue with 608 or Nufor, wide open or
   limited in format.
   ... We've implemented Auth0 with security based on IPv4
   lockdown approach.
   ... Haven't implemented handover functions, the idea that you
   may have more than one source of
   ... caption documents, and we have a model in Part 3 for
   passing over control seamlessly so everyone
   ... knows who is in control and where their data is going.
   Needs more ecosystem, lacking at the moment
   ... for testing and demonstration.
   ... "flying hours" - if we have used libraries with memory
   leaks etc then eventually things will go wrong.
   ... Until we have solid real world use we can't be 100% sure it
   is robust.
   ... Used for Department of Parliamentary Services, Australia
   with a web feed.
   ... Extended proof of concept, due to launch imminently.
   ... Second is "Intersub", real time transcript service.
   Currently Newfor, plan to migrate to Part 3, which
   ... will simplify the stack and remove newfor handling
   deduplication code.

   Andreas: Really good, thank you, very interesting!
   ... Next up, Marco.

   Marco: [trouble presenting]

   Andreas: I will take over and we come back to Marco.
   ... Our broadcasters are fine most of the time. They look for
   new solutions if current tech cannot solve
   ... their use cases.
   ... One problem in the past is live streaming of broadcast
   programmes with closed captions, not burned in,
   ... on the distribution channel.
   ... All of the chain is standardised especially at the end.
   There are stable and good standards to package
   ... EBU-TT-D and IMSC into MP4 and deliver it with DASH and
   HLS.
   ... To encourage implementation we did a demo that has been
   online for 1 or 2 years where we use the
   ... live broadcast signal and take out the subtitles and bring
   it into IMSC and deliver it over HLS and DASH.
   ... [shows live Bavarian broadcaster BR's output]
   ... Teletext subtitles translated into IMSC.
   ... How it works: for the encoding and packaging, receive SDI
   with embedded teletext subtitles in the VANC.
   ... They decode it and then translate it to TTML and package it
   in MP4 for the client. That works.
   ... But what if you have a non-broadcast workflow, for an
   online only platform with no broadcast chain.
   ... And our broadcasters say they have a couple of
   internet-only live events and they do not want to buy
   ... whole broadcast systems for these events to subtitle them.
   One way it could be done is that at the
   ... packaging side you receive the video and audio together and
   synchronise it and deliver as MP4 to the client.
   ... The scenario we would like to solve is to use EBU-TT Live
   for the contribution to the encoding layer.
   ... Also we would like to get people together like we did in
   the past with this CMAF/DASH demo.
   ... The challenge we have at the moment is to find a packager
   and encoder that would implement
   ... EBU-TT Live and the synchronising mechanism.
   ... It would also be possible to use a legacy format like
   Newfor and transmit teletext information.

   Matt: Newfor is not an open standard. Everyone who has a copy
   of it has inherited it rather than been
   ... able to obtain it!

   Andreas: And all of them use a different variation of this
   protocol.

   Pierre: Who created Newfor?

   Matt: Sysmedia, a guy called Andrew Lambourne who now works at
   the University of Sheffield Hallam I think.
   ... It's a simple serial style wrapper around the core Teletext
   page instruction, with a session, flow management,
   ... and wraps up what literally should be on the screen.

   Andreas: What we see as a chance is the next Olympics. We have
   heard they want to offer much more
   ... online than on broadcast, and they need to provide
   captions. That's the goal and we are really looking
   ... for a good working solution here.

   Matt: We did some work with Channel 4 in the UK, who broadcast
   the paralympics. They wanted to make
   ... it all accessible online and the only solution was to hire
   a crate of kit from the US, go to SDI and back
   ... out again, and doing that all cost quite a lot of money.
   The requirements really do exist.

   Andreas: Marco, can we hand over to you?

   Marco: [presents slides]
   ... [Status subtitle market]
   ... Global overview of what you all said, to make clear the
   Europe subtitle volume is extensive.
   ... Most countries have regulation with additional European
   regulation that will probably end up with
   ... having 100% hearing impaired subtitling. About 50% of
   Europe uses translation subtitles as well.

   Pierre: Checking my assumption, 5 years ago a lot of subtitling
   for translation but there is no [missed]

   Frans: Different per country

   Marco: The view is that accessibility needs to be at a higher
   level.

   Frans: Increasing pressure, depends how far people can go
   because of money.

   Pierre: On the accessibility standpoint, what is the coverage
   in Europe?

   Frans: Subtitling only (captioning), 100% in NW Europe.

   Marco: 95% on all content.

   Matt: Many countries it is only the public service broadcaster.

   Andreas: In Germany main channels 100%, major public ones,
   commercial ones down to 20%.

   Marco: Will change with new EU regs.

   Frans: Not sure timing

   Matt: Equivalent of the US regs

   Pierre: Public and commercial broadcasters?

   Frans: Not equal

   Andreas: Media industry requirements not so strict.

   Matt: Strange things - some countries have more stringent regs
   because of their governments but
   ... tech affects ability to deliver.

   Pierre: Statement that penetration will increase is because of
   regulation or cost?

   Marco: Regulation mainly.

   group: [everyone wants to see data on that!]

   Marco: On the translating part, a lot of countries have burned
   in subtitles too.
   ... Differs between countries, in Netherlands it is all foreign
   language.
   ... [Subtitle market status]
   ... Shift from linear broadcast to on-demand and OTT.
   ... New requirement for different devices not knowing Teletext.
   ... Teletext used in broadcast facilities, page 888 for the
   viewer, being phased out.
   ... Equipment is end of life, end of support, no new companies
   offering solutions.
   ... Typically something I run into, no Teletext support in
   encoders.
   ... Current support only goes to 7 lines, I need 15 or 16!
   ... Current tech support is cut off but IP protocols not there
   - we really need to do something new.
   ... New players on the market, mainly internet startups.
   ... Know a lot about new world interfaces.
   ... Need standardisation to get this streamlined.
   ... Increasing demand for good access services and
   customisation on client side, so not sending
   ... a rendered subtitle image but sending text so the front
   ends can customise.
   ... New volumes - non-audio videos without subtitles
   ... Looking at new functionality for web players, extra
   metadata etc.
   ... [EBU-TT as replacement]
   ... File based, not for today. Teletext based - all
   proprietary, being phased out.
   ... [Live transport in the chain] - picture from EBU spec,
   slightly modified.
   ... Live part from authoring facility to playout, then playout
   to encoding.
   ... EBU-TT Live -> EBU-TT-D/IMSC for player rendering and DVB
   ... [NPO's live subtitle chain]
   ... Live subtitle department done with one editor for simple
   programmes, and 3 editors for more complex
   ... talking heads programmes, with respeaking, correcting and
   cueing, with video delays. Very demanding
   ... for respeaking, so change editor roles during the
   programme.
   ... Also trying to do automated subtitling, really a challenge
   at the moment.
   ... Then playout, file based with STL and Cavena at the moment,
   need to go real time to encoder.
   ... As Andreas said, Newfor and Teletext are the old world.
   Looking toward having a new world approach
   ... where styling and formatting are equal and extendable
   through all devices.
   ... So we want block based subtitling, handover between
   editors, time relationship is SMPTE based but
   ... not always 'do it now' but could be late file delivery with
   overlaid live subtitles, then ingested during
   ... playout for replay later.
   ... Looking at media timecode in next generation which should
   last at least 3 years.
   ... Need to fan out to multiple destinations.
   ... Timebase processing (delay compensation)
   ... Lowest delay NOW (remote capability) is needed
   ... Same for file based playout.
   ... SMPTE timecode, timebase correction, fan out to multiple
   destinations, timed metadata.
   ... A TTML based approach really important for timed metadata.
   ... In encoder, fan-in from multiple sources, then synchronise
   ABR and DVN stream transport,
   ... subtitles and timed user metadata,
   ... join other worlds like HbbTV.
   ... [Needed] Widest standardization as possible.
   ... Currently have momentum to get rid of old world possibly,
   but tools not available for new world yet.
   ... Really frustrating.
   ... Good to mention need for multiple languages including right
   to left. We have a huge amount of Arabic
   ... in Holland.
   ... Near real-time in parallel to SMPTE 2110 ideally in future,
   encapsulated in distribution for client renderers.
   ... I hope to have some support for aligning positioning
   especially for converting from Teletext to new world.
   ... EBU-TT Part 2 includes some guidance.
   ... Would like to do the translation as early as possible in
   the chain.

   Andreas: Thank you for that honest but realistic view of what
   is happening and what the challenges are.
   ... Propose a break now for 15 minutes maximum.
   ... Return at 11:05.

   Nigel: Thank you for those presentations - they were really
   great!
   ... [return from break]

   Andreas: Can we start with a summary from yesterday?

   Nigel: Not sure exactly what you're referring to?

   Andreas: Yesterday it came up what could be done with EBU-TT
   Live and how to handle it in W3C.
   ... TTWG will have a new kind of layout a bit like CSS, where
   some functionality is taken out of the main
   ... specification and put into modules. This opens up a more
   flexible approach to address current
   ... requirements and parallelise activities so they do not
   block each other.
   ... In this context one of the proposals was to take the
   functionality and possibly the vocabulary of
   ... EBU-TT Live in a module published by W3C which then can be
   used by any profile of TTML, could be
   ... EBU-TT, IMSC or whatever.
   ... From my impression that's where it ended, it's a feasible
   approach.
   ... There are other questions how it could look at the end and
   the mechanics e.g. a submission from EBU
   ... as a W3C member. It is a feasible approach.

   Glenn: Clarifying my thinking on modularisation approach and
   how it is not exactly like CSS.
   ... In CSS they carved up the existing functionality of CSS2
   into pieces and called them modules.
   ... I'm not assuming and would oppose doing the same thing here
   with TTML3 because there are so many
   ... interlinked semantics between the different components and
   it would create quite a bit of effort to
   ... carve it into pieces and I don't see any advantage in
   evolution because it is fairly stable.
   ... What I see happening is in the context of TTML3 creating a
   new framework for modules to allow
   ... new functionality to exist that is not in TTML2.
   ... To the extent that we can put it into different module
   documents proceed on that basis.
   ... It may turn out that there are some substantive changes not
   in TTML2 2nd Ed that are appropriate
   ... for making in the core of TTML3 that are not in modules,
   but to the extent that we don't separate
   ... functionality then that would be the best approach,
   allowing parallelisation of work and editorial activities.
   ... Especially for new well identified groups of functionality
   such as live.
   ... Just communicating my understanding because that's what I'm
   going to operate on.
   ... If people differ from that I'd like to hear about it.

   Andreas: I think it would work well for this use case, and it
   would also be good to discuss why we have
   ... the discussion. Right now EBU-TT Live is complete and is
   out there. What are the benefits of bringing
   ... into W3C?
   ... 1. To encourage vendor support, by having a global
   solution.
   ... 2. I know there are ideas and requests for updates of
   functionality. Here it is better to do it in one
   ... group rather than separate groups.

   Nigel: Add one more, which is it would allow us to make a thing
   like IMSC Live, which currently seems to
   ... be excluded by EBU-TT Live even though in principle it is
   possible to make IMSC-conformant EBU-TT Live
   ... documents, I don't think that seems obvious to the wider
   world.
   ... Also there are some useful constructs permitted in IMSC
   that are excluded by EBU-TT Live.

   Andreas: That's right, and you also point to an important issue
   that EBU-TT Live is first a description
   ... of how a live TTML workflow should look, with some
   additional syntax and semantics.
   ... It is bound to EBU-TT syntax definition, so limited to what
   is in EBU-TT Part 1.

   Marco: Two main topics: The transport mechanism and the syntax
   of the documents.

   Andreas: Right.

   Nigel: In the EBU specs we've tackled them as separable things.

   Andreas: So 3 things: Workflow, Carriage mechanisms, and the
   payload.

   Marco: What I meant was the transport and how we encapsulate
   the handshake in mechanisms.

   Andreas: There are clear benefits also in the EBU group, and
   everyone involved in standardising EBU-TT Live
   ... is convinced of the usefulness here.
   ... It would be useful to hear from others in TTWG, Pierre,
   Glenn.

   Pierre: Yes, I don't have a very strong opinion about applying
   only to IMSC or to TTML as a module, I'm
   ... happy either way, whichever works best.
   ... I think it would be good to apply to IMSC somehow if it is
   possible.
   ... Last time I saw it it was merely a couple of additional
   attributes with no impact on visual presentation.
   ... The only feedback on the document that I have already
   shared is it is too long.
   ... Otherwise it seems like a good idea. I like the idea of
   trying to focus development on the technical
   ... specifications in a single place. The requirements can come
   from other groups.

   group: [general agreement]

   Frans: I totally agree, that is the main point.
   ... A second point is ease of marketing, branding, so
   considering a complete IMSC based future could be
   ... very attractive as the main thing people know about. We
   should embrace the best candidate we have
   ... and it is IMSC, that gives us the biggest chance of
   adoption.

   Pierre: Specifically on EBU-TT Live and authoring, with SMPTE
   2110 and the brave new world, it would be
   ... really good for this community to help folks pick the right
   technology, or someone will pick SMPTE-TT
   ... and say that's what we're doing now.
   ... My feedback to Nigel is the more we can do to narrow what
   goes over 2110 the better otherwise we
   ... will have disappointment, otherwise someone will implement
   TTML over 2110 and it won't work
   ... between vendors.

   Matt: I would like to see removal of specific protocols for
   individual markets, in favour of global ones
   ... To avoid lossy transcode, reworking, and support new
   languages.
   ... I've had conversations about Punjabi, Hindi, Mandarin,
   Cantonese (bizarrely), Arabic, they all need some
   ... kind of kludge.

   Pierre: Can we talk about 2110, how can we contribute
   positively?

   Nigel: On the point about TTML vs IMSC for this, there are
   other uses of TTML than subtitles, which
   ... may benefit from live contribution, like AD, as agreed
   yesterday, so it makes sense to put it there.
   ... On the 2110 issue, have to use TTML because that is what
   has the IANA registration.
   ... Also want to encourage use of codecs parameter from the
   beginning to avoid the non-adoption problem.
   ... Also we will need other specs like in SMPTE, NMOS and EBU
   to complete the suite.

   Frans: [scribe missed]

   Andreas: We are here because we want to work more closely
   together. This work counts the same,
   ... need to focus on working together and make sure as Pierre
   says that the major stakeholders align
   ... on one approach to solving a specific problem.
   ... Parallel solutions won't help.
   ... I'm not so familiar with IETF. Two forms of collaboration.
   One is publish something and let the domain
   ... submit some feedback, send comments back. This works not
   that well in the past because of workload.
   ... The other is getting together in a room and talking through
   the problem.
   ... I'm not sure about this particular work, BBC is submitter
   so that is helpful. The relevant people
   ... should come together and at least discuss this paper and
   agree it is the right approach.
   ... For SMPTE I'm not sure.

   Nigel: I've already received a request to discuss in W3C TTWG
   and am happy to do that.

   Frans: Putting together a timeline would be useful.

   Pierre: To better understand 2110, there's a bunch of
   specifications for audio and video but is there any
   ... about timed text today?

   Nigel: No there isn't yet.

   Pierre: I'd like to come back to that.

   Andreas: Okay, from the feedback so far I haven't heard anybody
   objecting the approach to bring the
   ... EBU-TT Live activity into W3C at least to mirror the most
   important parts of EBU-TT Live as a module
   ... in a W3C spec.

   Nigel: Is it clear to everyone what the syntax, semantics and
   general approach is?

   Andreas: We may not have time to go through it.

   Nigel: Just want to check if there is enough awareness to make
   a general decision.

   Glenn: What's the decision?

   Andreas: To bring the EBU-TT Live work into W3C

   Glenn: Sounds good to me, mutatis mutandis.

   Frans: To make IMSC Live?

   Andreas: First to bring into TTML, second should we say it is
   our goal to make IMSC usable together with
   ... this module, if it is a profile or an addition to IMSC has
   to be found out.
   ... The other thing I think is also important is to bring over
   these two attributes like multiRowAlign.
   ... Do we say the EBU-TT Live attributes are now handled in W3C
   space?

   Glenn: A more practical question - do we have a prospective
   editor?

   Andreas: We clarified this yesterday Nigel will be.

   Pierre: Do we need to make a decision today?

   Andreas: Let us see if we are ready for a decision!

   Pierre: On the namespace?

   Andreas: What do you mean? Concrete proposal: move the syntax
   and semantics into a TTML3 module
   ... without changing syntax, then add to IMSC Live.

   Glenn: I mentioned yesterday I would be amenable to enabling
   foreign namespace vocabulary in
   ... modules, so that could work for this and for multiRowAlign
   and linePadding.
   ... That would also in my mind be a potential incorporation of
   those into the TTML core but that is a
   ... future process to think about. By then it may be that we
   have acceptance of the use of foreign
   ... namespaces in TTML.

   Pierre: On the relationship with IMSC, maybe the jury is still
   out, but my understanding is that these are
   ... timing attributes added to a TTML document?

   Glenn: Almost like metadata.

   Pierre: Exactly, they're permitted additions that don't affect
   presentation.

   Andreas: Apart from timebase clock

   Nigel: Like a pre-processor that affects the time during which
   the document is active, otherwise yes the same.

   Pierre: We can just do it.

   Andreas: Both a technical and a marketing side to this.

   Frans: So we could end up in an ideal case in a few years with
   everything IMSC and the world is simple,
   ... that would be the best solution, forgetting TTML, EBU-TT
   all the rest of it.

   Matt: It is being adopted already without a second thought,
   seemingly, so it is free of geographical boundaries
   ... already I would say.

   Andreas: I don't think we need a final decision on this depth,
   but if we agree then we should prepare the
   ... next steps and propose it and do something similar as the
   two styling attributes.
   ... For me it is clearer we should handover maintenance and
   control of this to W3C.

   Nigel: If we are writing a liaison, a piece of paper, we can
   either cover all of it, or have two, one for
   ... styling and one for live.
   ... I've heard enough that there is consensus on our
   requirements issue to take it forward for this year.

   Pierre: A member submission would be the best thing.

   Nigel: Quite a lot of overhead in doing that, I'd rather start
   in W3C with an empty thing.

   Andreas: Proposing to hand over control over EBU-TT Live to
   TTWG, to republish EBU-TT Live as a module,
   ... further updates of EBU-TT Live done in the TTWG and not the
   EBU Timed Text group.

   Nigel: EBU should have the freedom to iterate its specs if it
   wants to do so.

   Frans: Query if we want to update EBU-TT Live or brand
   everything as IMSC Live.
   ... That's an important consideration. I would be in favour of
   steering everything towards IMSC.

   Nigel: I don't disagree, maybe EBU should publish something
   explaining this position to the world.

   Andreas: We are making an important shift, we may need to
   discuss this further. For me it makes more
   ... sense to make a cut and say we transfer it now to another
   organisation and will not update further.
   ... For the two vocabulary items we hand over control and if
   there are further EBU specfications we can
   ... publish a new spec referencing.

   Frans: What if there is a bug in EBU-TT Live?

   Andreas: If there is a short term need then we can do that
   otherwise we should not.

   Frans: I am not sure what timelines we are talking about.

   Marco: Isn't it about securing EBU requirements in a future
   spec?

   Frans: I feel confident about that.

   Andreas: We have enough shared members, we can collect
   requirements from the EBU and bring it into
   ... the new W3C spec but do not publish in EBU scope.

   Marco: That makes it clearer to the rest of the world.

   Frans: It is all about simplicity. In spirit we all agree.

   Andreas: Long term goal is agreed, need to figure out how it
   would work in the short term.

   Nigel: Checking in on the agenda, we've covered almost all the
   topics, 15 minutes to go.
   ... Pierre asked to come back to SMPTE 2110, and Andreas you
   wanted to come back to something too?

EBU and W3C collaboration

   Andreas: [shares screen]
   ... We have these two attributes, and part 1, and EBU-TT-D and
   part M.
   ... Starting with EBU-TT-D, one approach we could take that
   would benefit industry is to say we stop
   ... work on EBU-TT-D and point to IMSC for any future update,
   or missing functionality or bug fixes.
   ... That would be a clear message.
   ... We should try to elaborate if we can do something similar
   for Part 1 and Live.

   Nigel: I think a key point here is how we handle smpte and
   clock timebases, which are in EBU-TT and TTML
   ... for a reason, and not in IMSC also for good reasons. Can
   media time only work in playout scenarios?

   Marco: As a broadcaster, I can say it won't work for the next 3
   years.

   Andreas; Stick with what works and is available.

   Pierre: Exactly, that's what you have to do.
   ... You can adopt EBU-TT Part 1 today and constrain it. 3 works
   is a realistic horizon to work with
   ... vendors and service providers and say in 3 years we plan
   not to use timecode for those workflows.

   Marco: We always have legacy from our archives so we need some
   timebase transcoding somewhere.
   ... It's already on my list. I think I'm forward looking within
   the range of broadcast views!

   Frans: Absolutely. This is a very critical thing, we need to
   spell out the transition scenario, how does this
   ... work, what do you encounter in practice. If we cannot we
   are not in a good situation.

   Marco: We have to guarantee that what is in EBU-TT now remains
   the same in large part for IMSC.

   Pierre: Looking at the differences, is that the sum total?

   Andreas: Those are the main things on a quick look. The really
   substantive things are timecode and cell.
   ... Cells are manageable by translation to %.

   Pierre: Especially with IMSC 1.1 we have rh and rw so there is
   a lossless 1:1 translation from cell.

   Andreas: There's more work to be done that's clear.
   ... To say it is simple, everything IMSC, wherever it is, I see
   some kind of agreement that this is the long
   ... term goal, and possibly to come together and discuss it
   maybe at IBC. We can try to set up a new
   ... joint meeting at IBC.

   Pierre: What's the timeline for submission of EBU-TT Live and
   EBU-TT Part 1?
   ... And starting that convergence process.

   Andreas: For Part 1 it is different, we haven't started the
   discussion. For Live it is easier, depends on
   ... Nigel who has the most work on it.

   Pierre: That could be part of what we try to do this year with
   IMSC.

   Frans: To do the transfer, this year?

   Pierre: Yes, as well as other additions to IMSC that we have
   discussed, like embedded fonts.

   Nigel: I'm not clear what needs to be done to IMSC though?

   Pierre: Exactly, that is why I am optimistic.

   Andreas: The live module can be done this year.

   Pierre: And make a goal to resolve differences with EBU-TT Part
   1.

   Andreas: That is more complex, I don't see Part 1 alignment
   this year.

   Pierre: If we are targeting 3 years it would be ideal to do it
   this year.
   ... I think it would be different if there had been broad
   adoption of EBU-TT Part 1.

   Frans: I agree. We need a clear understanding of how it is
   used.

   Marco: For example live ingest - how do you translate that to
   time expressions in a Part 1 document.

   Pierre: What we saw yesterday is the bigger issue with live is
   not the timebase, but the separation of
   ... flows of audio/video and subtitles.

   Frans: But part 1 not live.

   Pierre: This will never be used in live?
   ... What would it be used for?

   Frans: Prepared content

   Pierre: Why use timecode?

   Marco: To synchronise with the playout server.

   Frans: Longer discussion!

   Andreas: We can schedule for live in W3C, for part 1 we need
   further discussions and we should have
   ... this kind of coming together.
   ... What about this goal to be at IBC.

   Nigel: Logistical issue of timing of meetings - TPAC is very
   close to IBC, I can't be at both probably.

   Frans: IBC is where we can collect user input. We need that.

   Andreas: We don't necessarily need the people in the room but
   we need the feedback channeled through us.

   Frans: IBC is an opportunity to meet industry people.

   Pierre: Do we present results or gather feedback?

   Frans: Both, there is not enough time to gather information
   about timecode usage at IBC

   Andreas: A half day workshop would be useful, after the
   standards people get together.

   Pierre: So present results at IBC.

   Frans: That would be great.

   Pierre: I'm pretty confident that North America is happy to use
   IMSC for production, I'll hear more in 2 weeks.
   ... For live I don't know.

   Matt: Live is typically 608 originated and delivered straight
   into EEG or Evertz encoders. It is ripe for evolution.

   Pierre: I don't know about live, I'm pretty sure IMSC will be
   good enough, I've not heard any objection to that.
   ... Would be good to hear from EBU members.

   Frans: It is an extremely early stage.

   Andreas: We can cover Live and EBU-TT-D at IBC.
   ... Then we can start to get out the message about part 1 but I
   agree with Frans it is more complicated.
   ... This overall meeting would be good.
   ... Nigel you say they are close together?

   Pierre: The only way I could do TPAC is to be there for a day
   and a half.

   Andreas: For the TTWG we had the idea to move the regular
   meeting out of TPAC. That would be a question
   ... if we would move the meeting to Amsterdam.

   Pierre: Tokyo would be a lot closer in travel time than
   Fukuoka!
   ... By the way I did complain to W3M and they said they don't
   have IBC and NAB on their calendars!
   ... They said it would be a good idea.
   ... The AC meeting is right on top of NAB and TPAC on top of
   IBC.

   Andreas: To sum up we try to move forward offline with EBU-TT
   Live as quickly as possible and we also
   ... have some discussion about EBU-TT-D and Part 1 and share
   info soon.
   ... Then we propose to both groups to have a domain meeting
   where we present our results but also a
   ... face to face meeting that would be joint EBU and TTWG. We
   have absent TTWG people today so we have
   ... to propose it.

   Pierre: If you're organising meetings at IBC you're not going
   to make it to TPAC.

   Matt: I would go to IBC but not TPAC.

   Frans: So hold an industry meeting and a joint meeting both at
   IBC?

   Matt: I'd request immediately before IBC or after, not during.
   ... So we travel to Amsterdam once and stay.
   ... If we could do it on the Thursday that would be good for
   me.
   ... I will be busy after then.

   Andreas: That makes sense.

   Matt: I'm usually exhausted by the Tuesday.

   Andreas: We need to discuss this in the TTWG.

   Pierre: If TTWG is not going to meet at TPAC that would be good
   to know as early as possible.

   Andreas: It would be good to send a message out at IBC.

   Matt: Possibly arrange a presentation, say in the innovation
   presentation area.

   Andreas: Those are the things that come to my mind. Anything
   else we need to discuss or finalise?

   Pierre: Is it bad not to attend TPAC?

   Thierry: There's nothing mandatory but it is convenient for
   coordinating with other groups. There are no
   ... rules about it, it is just for convenience.
   ... The dates for meeting would be?

   Andreas: We need to check it offline.

   Pierre: Either Thursday 12th Sep or Tuesday 17th.

   Andreas: If nothing else we can close the joint meeting.

   Nigel: Thank you everyone, a good morning's work and good
   discussion, we can adjourn now.
   ... [adjourns meeting]

Summary of Action Items

Summary of Resolutions

   [End of minutes]
     __________________________________________________________


    Minutes manually created (not a transcript), formatted by
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