14:58:28 <RRSAgent> RRSAgent has joined #tt
14:58:28 <RRSAgent> logging to https://www.w3.org/2021/09/02-tt-irc
14:58:30 <Zakim> RRSAgent, make logs Public
14:58:32 <Zakim> Meeting: Timed Text Working Group Teleconference
14:58:38 <nigel> Present: Nigel
14:58:45 <nigel> scribe: nigel
15:01:19 <nigel> Present+ Mike, Chris
15:01:36 <cpn> cpn has joined #tt
15:01:46 <nigel> Present+ Pierre
15:02:04 <cyril> cyril has joined #tt
15:02:34 <nigel> Present+ Cyril
15:02:42 <mike> mike has joined #tt
15:02:51 <cpn> present+ Chris_Needham
15:03:02 <nigel> present+ Gary
15:03:18 <nigel> present- Chris
15:03:24 <pal> pal has joined #tt
15:03:31 <nigel> Present+ Andreas
15:03:40 <nigel> Present+ Glenn
15:04:17 <nigel> Chair: Gary, Nigel
15:04:23 <nigel> Topic: This meeting
15:04:40 <cyril> scribe: cyril
15:04:44 <glenn> glenn has joined #tt
15:05:11 <cyril> nigel: we have a topic on HRM and I'd like to move that to the end because Chris is here for 30min
15:05:20 <cyril> ... and we need to discuss joint meetings first
15:05:32 <cyril> ... there is also a discussion on how we do tests
15:05:44 <cyril> ... the last topic is the charter
15:05:58 <cyril> ... it expires at the end of the year and it might take 3 months to prepare it
15:06:20 <cyril> Topic: Joint meeting requests
15:06:23 <atai> atai has joined #tt
15:07:07 <cyril> pal: the HRM topic is really time sensitive and crucial
15:07:12 <cyril> mike: +1
15:07:39 <cyril> nigel: TPAC is virtual only
15:07:51 <cyril> ... we've had requests/suggestions for joint meetings
15:08:01 <cyril> ... the first one with explicit request is Media Synchronization
15:08:14 <cyril> ... there is work on progress on Sync and User Accessbility
15:08:24 <cyril> ... it's a companion to MAUR
15:08:33 <cyril> they've asked us for time
15:09:05 <cyril> ... at 10 amET, 14UTC
15:09:49 <cyril> ... 20th October
15:09:54 <cyril> ... any objections?
15:10:29 <cyril> RESOLUTION: We accept the meeting with APA to discuss SAUR
15:10:46 <cyril> nigel: there are 3 other groups we could meet with
15:11:02 <cyril> ... MEIG: I'm not clear what agenda topic we could usefully discuss
15:11:06 <cyril> ... anybody has topics?
15:11:26 <cyril> cpn: the IG is not planning to take updates
15:11:38 <cyril> ... if we don't have specific topics we could cancel
15:12:03 <cyril> gkatsev: we could discuss unbounded cues but we can schedule those as we are doing
15:12:15 <cyril> cpn: which reminds me to schedule the next one
15:12:30 <cyril> nigel: in the absence of proposal to have a joint with MEIG, we will not request one
15:12:42 <cyril> nigel: next group is Media WG, working on the next version of MSE
15:13:03 <cyril> ... they will publish FPWD of MSE v2, which continues to include support for Text Tracks
15:13:07 <cyril> cyril: only in the spec ...
15:13:24 <cyril> nigel: same question, any benefit in having a joint meeting, any topic worth discussing?
15:13:36 <cyril> cpn: there was the generic text track cue proposal
15:13:46 <cyril> ... is there anything there that needs further discussion?
15:14:03 <cyril> gkatsev: it could be useful if we could get more buy in from vendors
15:14:22 <cyril> nigel: should we start talking about it only when we have more buy in?
15:14:38 <cyril> gkatsev: maybe we just need to do it offline, but it's worth reminding people about it
15:14:58 <cyril> glenn: we've been repeating that for 2-3 TPAC, with nods, but nothing happens
15:15:05 <cyril> ... not sure, it's worth the effort
15:15:12 <cyril> cpn: it does not have to be a TPAC thing
15:15:18 <cyril> ... we can do it at anytime
15:15:31 <cyril> ... no pressure from the Media WG AFAIK
15:15:40 <cyril> gkatsev: I can't think of anything urgent
15:16:03 <cyril> glenn: they should start implementing
15:16:13 <cyril> gkatsev: Safari has implemented and shipped
15:16:36 <cyril> nigel: do we want to increase communication around it to push other implementors to implement
15:16:56 <cyril> gkatsev: we can bring it to one of their working group regular meetings
15:17:34 <cyril> nigel: let's have the conversation between the chairs of the groups
15:18:05 <cyril> ... happy to ask Apple if they are willing to report on how it's going
15:18:12 <cyril> ... offline
15:19:00 <cyril> glenn: we had a few people attend this group in the past
15:19:06 <cyril> nigel: yeah, I know who to ask
15:19:22 <cyril> nigel: We will not request a joint meeting with Media WG
15:19:34 <cyril> nigel: next is the CSS WG
15:19:46 <cyril> ... there is a limited amount we could discuss
15:19:58 <cyril> ... in the past they have worked on feature for us, but they are not implemented
15:20:12 <cyril> ... we're a bit stuck if we are not CSS implementers
15:20:22 <cyril> ... I don't think there's been any change since last TPAC
15:20:32 <cyril> ... any topics?
15:20:36 <cyril> (silence)
15:20:43 <cyril> nigel: ok, nothing to add
15:20:54 <cyril> nigel: We will not request a joint meeting with the CSS WG
15:21:24 <cyril> Topic: Charter
15:21:33 <cyril> nigel: atsushi is not here
15:21:43 <cyril> ... but usually the chair works on a draft
15:21:54 <cyril> ... I reviewed ours
15:22:14 <cyril> ... there isn't a huge amount that we want to change
15:22:26 <cyril> ... if we want to continue TTML3 we should be clear about the goal
15:22:45 <cyril> ... we one thing we talked about doing is creating a version of TTML that is based on CSS
15:23:00 <cyril> ... WebVTT is still in there and has been in CR for the entire charter
15:23:19 <cyril> ... I don't know if there will be pressure from W3C to move it one way or the other
15:23:28 <cyril> ... the last thing is TTML profile for Audio Description
15:23:38 <cyril> ... we produced an ED but not a FPWD
15:24:20 <cyril> ... we need to understand the deliverables people want to work on
15:24:34 <cyril> ... otherwise we'll be a maintenance group
15:24:46 <cyril> pal: any reason not to be a maintenance group?
15:25:03 <cyril> nigel: recently, W3C moved away from having maintenance group
15:25:23 <cyril> ... we could have one cycle of maintenance but maybe not 2
15:25:38 <cyril> pal: I have a different feeling, they want to make it easy to maintain spec
15:25:45 <cyril> nigel: maybe without having a group
15:26:24 <cyril> atsushi: W3C defines a maintenance
15:26:28 <cyril> ... for example SVG
15:26:39 <cyril> ... update on specification
15:26:53 <cyril> ... restricted on non normative features
15:26:57 <cyril> ... fixing bugs is ok
15:27:01 <cyril> ... but no new features
15:27:13 <cyril> ... no large normative items
15:27:31 <cyril> ... TTML 2nd edition has not reached recommendation
15:27:56 <cyril> nigel: I'd like for anybody to let me, Gary and Atsushi if they want anything specific included in the next charter
15:28:06 <cyril> ... we'll incorporate than in the draft for review
15:28:10 <cyril> gkatsev: agree
15:29:01 <cyril> nigel: there is also the option to extend the charter, but there may be constraints
15:29:16 <cyril> atsushi: usually we extend for 6 months depending on how long we bring existing CR to REC
15:29:48 <cyril> nigel: I propose we don't try to rely on extension unless we have to
15:30:12 <cyril> glenn: a 6 months extension to gettting TTML2 to REC would be pointless unless we have implementation commitment
15:30:16 <cyril> nigel: I agree
15:30:38 <nigel> [chris leaves]
15:31:06 <cyril> Topic: TTML Tests
15:31:35 <cyril> nigel: I don't propose to go into the details on history
15:31:50 <cyril> ... but a keen observer we'll get a sense of why I'm proposing that
15:31:58 <cyril> ... 2 things I want to cover
15:32:08 <cyril> ... we have a clear working mode to make changes to our spec repo
15:32:33 <cyril> ... which is that we open an issue, describe what happens, open a PR, the group has minimum 2 weeks
15:32:42 <cyril> ... and we don't merge until we have at least 1 approval
15:32:50 <cyril> ... unless there is an urgency
15:33:01 <cyril> ... it's been unclear for our test repository
15:33:12 <cyril> ... I'm proposing to adopt the same process for tests
15:33:20 <cyril> cyril: agree
15:33:27 <cyril> glenn: no issue with that
15:33:43 <cyril> ... one of the reasons we were more flexible previously was
15:34:09 <cyril> ... during the CR and implementation reports period, we were rapidly changing those and not calling for a group review
15:34:34 <cyril> ... but now that things have stabilized more, I don't have objections to following the 2 week period review
15:35:25 <cyril> RESOLUTION: The group adopts the same process for test repo changes as for spec repo changes
15:35:44 <cyril> ACTION: Nigel to apply to the same protection changes
15:36:02 <cyril> nigel: next proposal is about test expectations and references
15:36:09 <cyril> ... for most tests we have some
15:36:21 <cyril> ... maybe not formally required for pass, but useful
15:36:27 <cyril> ... generated with TTPE in SVG form
15:36:41 <cyril> ... for IMSC, they are generated by IMSC in PNG form
15:36:54 <cyril> ... given that we don't generally require pixel accuracy for tests
15:37:11 <cyril> ... but things like order of glyphs are fixed and not subject to SVG renderers
15:37:28 <cyril> ... I'd suggest it to be good to have PNG renderings of the SVG versions
15:37:48 <pal> q+
15:38:25 <cyril> glenn: the original reason I had included expectations in the TTML repo is: 1) to give an ability to view a rendering, documented in the readme of both test repos
15:38:40 <cyril> ... it clearly states it is for sample purposes, not claiming correctness
15:38:54 <cyril> ... and the group did not review those to agree or not
15:39:05 <cyril> ... 2) I needed a way to perform regression testing on TTPE
15:39:28 <cyril> ... at some point instead of storing in the TTPE repo, I decided to use submodules in git and point to the W3C repo from the TTPE repo
15:39:36 <cyril> ... that made them strongly bound together
15:40:10 <cyril> ... so if I made changes to the TTPE code that changed the rendering, e.g. grouping hierarchy, changing the SVG but not the rendering
15:40:19 <cyril> ... I was using Chrome as my sample rendering
15:40:31 <cyril> ... then I needed to change those expected renderings
15:40:43 <cyril> ... when I updated them recently, there were questions about that
15:41:04 <cyril> ... in reviewing that decision to tie the 2 repos, I made the decision to revert that dependency
15:41:14 <cyril> ... and to disconnect TTPE's repo from W3C's repo
15:41:37 <cyril> ... it's not the business of W3C to help the regression testing of one implementation
15:41:56 <cyril> ... so I removed the dependency from TTPE
15:42:03 <cyril> ... and removed expectations from W3C
15:42:22 <cyril> ... my proposal is just to leave the test without the SVG TTPE expectations
15:42:30 <cyril> ... if the group wants PNG, that can be done
15:43:05 <cyril> nigel: I largely agree with that. W3C are not there to support a particular implementation.
15:43:18 <cyril> ... also there has not been a review of the SVG expectations
15:43:24 <cyril> ... however they are useful
15:43:39 <cyril> ... they would create a more complete test
15:43:56 <cyril> ... I think it would be useful generally to take those as some form of reference
15:44:15 <cyril> ... implementations can compare
15:44:36 <cyril> ... for me a test repo without some form of rendering is not that useful
15:44:56 <cyril> ... that only applies to presentation tests
15:45:18 <cyril> glenn: AFAIK the group has not reviewed the SVG for IMSC
15:45:29 <cyril> ... I'd prefer to remove the SVG files
15:45:37 <cyril> ... I don't intend to support them in the future
15:45:43 <cyril> ... within the W3C test repo
15:45:52 <cyril> ... I will be updating only the TTPE repo
15:45:57 <cyril> q+
15:46:37 <cyril> pal: I think there is no need to require PNG or SVG
15:46:46 <cyril> ... I'm not sure what question is being asked at this point
15:46:58 <cyril> nigel: are you happy to have a test repo without rendering?
15:47:11 <cyril> pal: it's much better if it is there, but requiring won't help
15:47:15 <nigel> scribe: nigel
15:47:32 <nigel> Cyril: If we keep the SVG in the repo we should be clear that it might make it difficult
15:47:45 <nigel> .. for others to produce tests - it is much easier for most implementations to produce PNG than SVG.
15:47:47 <cyril> cyril: it's much easier to produce a PNG than an SVG for most implemtation
15:47:57 <cyril> ... we should be clear not to require SVG
15:48:14 <nigel> Glenn: I did actually code up a tool to convert SVG into PNG using a library called librsvg however the quality of its output is not as good as
15:48:23 <nigel> .. the renderings in Chrome, or some of the other browsers.
15:48:31 <nigel> .. It would be a degraded PNG but it would be something.
15:48:51 <nigel> .. It's probably a week or less work to generate PNG from the SVGs that are currently in the repo.
15:48:59 <nigel> ack pal
15:49:02 <nigel> ack cyril
15:49:07 <cyril> scribe: cyril
15:49:30 <cyril> nigel: I agree we need to be clear on the requirements to add new tests, to make it achievable
15:49:36 <cyril> ... I don't think we need a resolution
15:49:55 <cyril> ... but I would request that we don't remove the SVGs while we study how to generate PNGs
15:50:06 <cyril> glenn: ok, I will not merge the PR yet
15:50:10 <cyril> Topic: IMSC HRM
15:50:23 <cyril> nigel: pal you said there is a time urgency, can you explain?
15:50:29 <cyril> pal: there is now an HRM validator
15:50:42 <cyril> ... folks are integrating them in their workflow and files are failing
15:50:52 <cyril> ... we have one concrete report and 2 issues
15:51:36 <cyril> ... the 2 issues are: one where today the complexity of painting background behind spans is the same complexity as painting the region. It's too simple.
15:51:55 <nigel> q+ to ask about render success for documents that fail HRM now
15:52:08 <cyril> ... the other one is the fact that clearing the root container has a cost even if the previous ISD is an empty ISD which already caused to clear
15:52:24 <cyril> ... I want to ask if there is any strong feelings on these 2 issues
15:52:30 <cyril> ... I could prepare PR
15:52:37 <nigel> ack nigel
15:52:37 <Zakim> nigel, you wanted to ask about render success for documents that fail HRM now
15:52:51 <cyril> nigel: there are some real world documents that fail the HRM
15:53:08 <cyril> ... given the purpose of the HRM is to make sure that real world documents render
15:53:33 <cyril> ... do we have data that shows that these real world documents render on real world devices
15:53:47 <cyril> pal: in those cases, the HRM is clearly erroneous
15:53:53 <mike> q+
15:54:19 <cyril> nigel: the screen clearing after empty ISD, the ticket is clear that it is excluding existing authoring practice
15:54:26 <cyril> ... the span issue is not that clear
15:54:40 <cyril> pal: but again, the algorithm in the HRM is non-sensical
15:54:54 <cyril> ... as the region becomes larger, it does not make sense
15:54:57 <nigel> ack mike
15:55:15 <cyril> mike: to your question about evidence, there is no way to quantify that for 2 reasons:
15:55:32 <cyril> ... we don't have access to all renderers in the world, finding one is not sufficient
15:55:40 <cyril> ... and the failure is not obvious
15:56:23 <cyril> ... we need to rely on the argument of what's reasonable, have we made mistakes, ...
15:56:34 <cyril> ... I don't remember how much it was modified from DECE's version
15:56:46 <cyril> nigel: small changes were made, but left mostly intact
15:57:39 <cyril> pal: what I'm proposing to do is to fix what looks like a defect, update the code and iterate
15:57:48 <cyril> ... see if changes break players
15:58:07 <cyril> mike: this would be a revision to IMSC 1.x
15:58:27 <cyril> pal: assuming we are ok to make those changes, what I would propose is to factor out the HRM to a separate doc
15:58:40 <cyril> ... as a WG Note first and once we're happy we can put it back
15:58:56 <cyril> nigel: that is a deliverable that we would need in the charter
15:59:24 <cyril> cyril: are there players that rely on the HRM?
15:59:29 <cyril> pal: I don't know
15:59:34 <cyril> mike: I doubt that
15:59:49 <cyril> pal: when we make that change, we might have other changes to make
15:59:58 <cyril> ... we should leave the door open
16:00:11 <cyril> nigel: it's a good approach to structure things to make changes easy
16:00:24 <cyril> mike: this has been an invaluable tool for real time transcoders
16:00:41 <cyril> ... people started creating full documents 30 times per second
16:01:23 <cyril> ... because you can point to definitive perfomance criteria
16:02:19 <cyril> ... without HRM, encoder implementors can produce documents that make decoding implementations ver difficult to get good results
16:02:33 <cyril> nigel: you're requesting the go ahead to make PR
16:02:42 <cyril> ... my summary is that you have the go
16:02:50 <cyril> pal: and what about the WG Note?
16:03:27 <cyril> ... start with a WG Note for today, the charter can mention REC track
16:03:46 <cyril> nigel: you can start with a REC track document, that's in the spirit of the current charter and that's a refactoring
16:03:54 <cyril> pal: ok
16:04:27 <cyril> pal: can you create a new repo?
16:04:36 <cyril> nigel: I might need help from atsushi
16:04:59 <cyril> ... we should call imsc-hrm
16:05:06 <cyril> pal: yes
16:05:13 <cyril> atsushi: I will work with nigel on this
16:06:04 <nigel> scribe: nigel
16:06:07 <nigel> Topic: Meeting close
16:06:23 <nigel> Nigel: Thank you everyone - it's been a very productive meeting, apologies we went 5 minutes over.
16:06:26 <nigel> .. [adjourns meeting]
16:06:32 <nigel> rrsagent, make minutes
16:06:34 <RRSAgent> I have made the request to generate https://www.w3.org/2021/09/02-tt-minutes.html nigel
16:10:18 <nigel> Present+ Atsushi
16:12:17 <nigel> s/Topic: Joint meeting requests//
16:12:25 <nigel> i/nigel: TPAC is virtual/Topic: Joint meeting requests
16:12:57 <nigel> rrsagent, make minutes
16:12:57 <RRSAgent> I have made the request to generate https://www.w3.org/2021/09/02-tt-minutes.html nigel
16:16:19 <nigel> s/they've asked us for time/.. they've asked us for time
16:18:26 <nigel> s/to let me, Gary and Atsushi if/to let me, Gary and Atsushi know if
16:19:13 <nigel> i/pal: I have a different feeling/[atsushi joins]
16:19:44 <nigel> s/a keen observer we'll get/a keen observer will get
16:20:30 <nigel> s/Nigel to apply to the same protection changes/Nigel to apply the same branch protection rules to the test repos as the spec repos
16:21:19 <nigel> s/implementations can compare/implementations can compare and raise issues if they differ
16:22:02 <nigel> s/Cyril: If we keep the SVG in the repo we should be clear that it might make it difficult//
16:22:26 <nigel> s/.. for others to produce tests - it is much easier for most implementations to produce PNG than SVG.//
16:22:49 <nigel> i/cyril: it's much easier to produce/scribe: cyril
16:23:00 <nigel> i/Glenn: I did actually code/scribe: nigel
16:23:08 <nigel> rrsagent, make minutes
16:23:08 <RRSAgent> I have made the request to generate https://www.w3.org/2021/09/02-tt-minutes.html nigel
16:25:09 <nigel> s/we would need in the charter/we could add to the charter
16:25:41 <nigel> rrsagent, make minutes
16:25:41 <RRSAgent> I have made the request to generate https://www.w3.org/2021/09/02-tt-minutes.html nigel
16:28:01 <nigel> s/nigel:/Nigel:/g
16:28:06 <nigel> s/mike:/Mike:/g
16:28:13 <nigel> s/cpn:/Chris_Needham:/g
16:28:23 <nigel> s/gkatsev:/Gary:/g
16:28:31 <nigel> s/glenn:/Glenn:/g
16:28:45 <nigel> s/atsushi:/Atsushi:/g
16:28:57 <nigel> s/pal:/Pierre:/g
16:29:07 <nigel> rrsagent, make minutes
16:29:07 <RRSAgent> I have made the request to generate https://www.w3.org/2021/09/02-tt-minutes.html nigel
16:29:52 <nigel> s/cyril:/Cyril:/g
16:30:21 <nigel> rrsagent, make minutes
16:30:21 <RRSAgent> I have made the request to generate https://www.w3.org/2021/09/02-tt-minutes.html nigel
16:31:00 <nigel> scribeOptions: -final -noEmbedDiagnostics
16:31:07 <nigel> zakim, end meeting
16:31:07 <Zakim> As of this point the attendees have been Nigel, Mike, Chris, Pierre, Cyril, Chris_Needham, Gary, Andreas, Glenn, Atsushi
16:31:09 <Zakim> RRSAgent, please draft minutes v2
16:31:09 <RRSAgent> I have made the request to generate https://www.w3.org/2021/09/02-tt-minutes.html Zakim
16:31:12 <Zakim> I am happy to have been of service, nigel; please remember to excuse RRSAgent.  Goodbye
16:31:16 <Zakim> Zakim has left #tt
16:31:57 <nigel> Agenda: https://github.com/w3c/ttwg/issues/196
16:32:04 <nigel> Previous meeting: https://www.w3.org/2021/07/22-tt-minutes.html
16:32:07 <nigel> rrsagent, make minutes
16:32:07 <RRSAgent> I have made the request to generate https://www.w3.org/2021/09/02-tt-minutes.html nigel