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15:00:40 <cyril> trackbot, start meeting
15:00:43 <trackbot> RRSAgent, make logs public
15:00:46 <trackbot> Meeting: Timed Text Working Group Teleconference
15:00:46 <trackbot> Date: 18 July 2019
15:01:24 <cyril> scribe: cyril
15:01:28 <cyril> chair: Nigel
15:01:34 <cyril> agenda: https://github.com/w3c/ttwg/issues/48
15:01:48 <cyril> Present: Cyril, Gary, Andreas, Nigel
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15:02:28 <cyril> Present+ Atsushi
15:03:19 <cyril> Topic: this meeting
15:03:29 <cyril> Present+ Glenn
15:04:38 <cyril> nigel: we are still missing Mike so we cannot talk about profile registry
15:04:51 <cyril> cyril: but I don't think we need to discuss it, I have an action
15:05:08 <cyril> glenn: I prefer to have a proposal and then discuss based on it
15:05:33 <cyril> nigel: we will discuss progress towards CR for WebVTT
15:05:50 <cyril> gkatsev: yes, there is some progress
15:06:00 <cyril> nigel: 2 issues on TTML 2 that I think need discussion
15:06:18 <cyril> ... we can discuss the region-timing test
15:06:32 <cyril> ... I put charter status update if he joins
15:06:44 <cyril> ... TPAC planning also is on the agenda
15:07:05 <cyril> ... any other business ?
15:07:18 <cyril> glenn: I'd like to go over PR 1092
15:07:31 <cyril> nigel: I'm aware that you are waiting for feedback
15:07:37 <cyril> ... ok if we have time
15:07:40 <nigel> s/1092/1096
15:07:54 <cyril> Topic: WebVTT
15:08:44 <cyril> s/Topic: WebVTT//
15:08:57 <cyril> nigel: the review of PR is a bit difficult and we are working on that
15:09:00 <cyril> Topic: WebVTT
15:09:15 <cyril> gkatsev: the big thing that we last discussed was interop in parsing of region lines
15:09:28 <cyril> ... spec says integer, Safari and Firefox do different things
15:09:42 <cyril> ... I spoke with FF and they are fine with rounding
15:09:46 <cyril> ... so I have a change for that
15:09:53 <cyril> ... borrowed from the HTML spec
15:10:01 <cyril> ... Silvia approved it
15:10:09 <plh> plh has joined #tt
15:10:14 <cyril> ... if any body has feedback
15:10:27 <cyril> ... I have updated the snapshot for at-risk
15:10:35 <cyril> ... it should be reviewed
15:10:51 <gkatsev> -> https://github.com/w3c/webvtt/pull/470 update region line parsing
15:11:03 <gkatsev> -> https://github.com/w3c/webvtt/pull/460 new snapshot
15:11:32 <cyril> nigel: PR preview does not seem to work
15:11:40 <cyril> ... but there is a link in 460
15:11:56 <cyril> gkatsev: maybe because it's a change to the archive
15:12:00 <plh> 45211
15:13:08 <cyril> nigel: process-wise we will review those and when there is consensus, merge them and propose new CR
15:13:12 <cyril> ... is that the plan?
15:13:15 <cyril> gkatsev: yes
15:13:43 <cyril> ... the CR stuff is in the snapshot #460 but because there are changes that we want to make permanently, I created a separate PR for the main spec
15:13:54 <cyril> nigel: those changes from 470 are also in 460 ?
15:13:57 <cyril> gkatsev: yes
15:14:07 <nigel> q?
15:14:14 <cyril> Topic: TTML2
15:14:21 <cyril> nigel: we'll cover the issues first
15:14:32 <cyril> ... 943 ?
15:14:42 <nigel> Topic: Improve interoperability of non-negative-real and xs:decimal. ttml2#943
15:14:47 <nigel> github: https://github.com/w3c/ttml2/issues/943
15:15:04 <cyril> nigel: this issue is about allowing zero point to be valid
15:15:09 <cyril> ... it is not at the moment
15:15:17 <cyril> ... glenn's proposal is to permit it
15:15:23 <cyril> ... there is a PR for this
15:15:35 <cyril> glenn: I restarted the original PR that had been done last year
15:15:43 <cyril> ... I updated based on the current master
15:16:08 <cyril> nigel: this means that a previous non-conformant document would become conformant
15:16:16 <cyril> glenn: technically yes
15:16:29 <cyril> ... but it was never the intention to make that non-conformant
15:17:35 <nigel> q?
15:18:54 <nigel> -> https://www.w3.org/TR/xmlschema-2/#decimal xs:decimal definition
15:19:24 <cyril> cyril: is '0.' allowed in xs:decimal?
15:22:07 <cyril> cyril: it seems that it is allowed according to section "3.2.3.1 Lexical representation"
15:22:25 <cyril> nigel: but the fact that the . is the last character is a bit confusing
15:22:36 <cyril> gkatsev: but it says that trailing 0 are optional
15:23:17 <nigel> q+
15:23:53 <cyril> glenn: we changed the schema since then to use xs:string
15:24:10 <cyril> ... that change was based on the comment of July 21, last year
15:24:53 <nigel> q?
15:24:53 <cyril> ... we just need to widen the expression for non negative real
15:25:28 <cyril> nigel: this change makes non negative real, the + becomes a *?
15:25:36 <cyril> glenn: no it adds a new line
15:26:03 <cyril> ... you need the full stop to denote it's a real number
15:26:14 <cyril> nigel: ok, it makes sense
15:26:34 <cyril> ... the idea of making non negative real coincident with xs:decimal makes sense
15:26:44 <cyril> ... it makes it easier to write the schema
15:27:11 <cyril> ... seems like a good change to me
15:27:29 <cyril> cyril: is it affecting only gain and pan?
15:27:34 <cyril> nigel: a lot of things
15:27:57 <cyril> ... lengths, gain, pan, ...
15:28:09 <cyril> ... pitch, percentage uses number
15:28:25 <cyril> ... a lot of things would be affected by this
15:29:03 <cyril> Present+ Pierre
15:29:50 <cyril> pal: I'm looking at ttval
15:30:38 <cyril> ... so now non-negative real always has a dot
15:30:46 <cyril> ... but not a dot by itsefl
15:30:56 <cyril> s/itsefl/itself/
15:31:17 <cyril> nigel: it's good to look at implementation
15:31:43 <cyril> ... just checking EBU-TT impl, 1. would not match, but 1.0 would
15:32:26 <cyril> pal: it seems ttval would reject 0. but I need to check
15:33:01 <cyril> nigel: it might make some existing implementations non conformant
15:33:15 <cyril> ... I'm beginning to think it's a problem
15:34:22 <cyril> glenn: there is no requirement to backport it to TTML1
15:34:48 <cyril> ... it would potentially make validation tools not implementing 2nd ed more restrictive
15:35:12 <cyril> ... not sure what the roll out status of TTML2 in the industry
15:35:20 <cyril> ... but that would improve the status of interop
15:35:33 <cyril> nigel: that would be a change for IMSC 1.1 also
15:36:13 <cyril> cyril: I would say we shouldn't do syntactic changes unless it's broken
15:36:35 <cyril> pal: if we have several such changes, we could accumulate them and wait
15:36:56 <cyril> ... it would make it easier to include this one
15:37:13 <cyril> glenn: I'm not sure I agree that it's a breaking change
15:38:15 <cyril> nigel: it's not a document breaking change, but an implementation breaking change
15:38:44 <cyril> cyril: I think people should look at their implementations and we can take a decision based on that
15:39:01 <cyril> nigel: if this would be the only syntactical change, then it might not be worth
15:39:21 <cyril> glenn: we already approved some changes
15:39:55 <cyril> cyril: it would be good to have a list of those
15:40:31 <cyril> glenn: we changed the content body to add audio
15:40:58 <cyril> nigel: summary: group to study implementation impact and add review comments
15:41:08 <cyril> pal: and if we do it, we should have a test for that
15:41:39 <nigel> Topic: Remove xml:base and @condition from chunk. ttml2#961
15:41:45 <nigel> github: https://github.com/w3c/ttml2/issues/961
15:42:13 <cyril> nigel: a year ago, we discussed xml:base on the chunk element
15:42:21 <cyril> ... with no apparent use
15:42:36 <cyril> ... actually, xml:base is used to process condition
15:43:06 <cyril> ... so it was proposed to remove condition
15:43:35 <cyril> ... assuming positions haven't changed, it's to remove both, on the purpose that they do not serve any purpose
15:43:51 <cyril> glenn: the PR that I raised is a resurrection of the one last year
15:44:13 <cyril> ... there is a significant different in putting condition on chunk vs. source
15:44:20 <cyril> s/different/difference/
15:44:57 <cyril> cyril: would there be an interop problem if I used them?
15:45:11 <cyril> glenn: it's quite dangerous, and you should not do that
15:45:30 <cyril> ... I think that was an error when we authored it
15:45:42 <cyril> nigel: is it safe to say that there are other ways to do the same thing?
15:46:17 <cyril> ... like putting condition on something else
15:46:21 <cyril> glenn: yes
15:46:29 <cyril> ... you could have a multi-entry source
15:47:37 <cyril> ... I could dream-up use cases, not obvious that might use that
15:47:51 <cyril> ... but I'm pretty convinced that it's dangerous, security impact
15:48:10 <cyril> ... because you cannot decode the bytes until presentation time
15:48:16 <nigel> q?
15:48:20 <cyril> ... and so cannot determine that you have a valid resource
15:48:20 <nigel> ack n
15:49:36 <cyril> cyril: I don't have a strong opinion on this, as we have not implemented it
15:49:47 <cyril> ... but we should refrain from making changes unless it's broken
15:50:01 <cyril> ... we could add a note without making changes
15:50:13 <cyril> glenn: my claim is that it is broken
15:50:56 <cyril> nigel: despite my comment in the issue, I think I've changed my mind and agree with Glenn
15:52:12 <cyril> q+
15:52:49 <cyril> ... if you are worried of buffer overflow, that can happen with chunks or sources, regardless of whether condition is used
15:53:01 <cyril> pal: I don't have a strong opinion on this
15:53:46 <nigel> q+ pal
15:53:49 <nigel> ack cy
15:54:32 <cyril> cyril: chances that people have authored documents with this feature is low
15:54:48 <cyril> ... and it would not require people to change their implementation
15:54:53 <cyril> ... so I'm fine with it
15:54:56 <nigel> ack pal
15:55:10 <cyril> pal: we really need tests
15:55:19 <cyril> ... maybe that will limit us
15:55:32 <cyril> nigel: right, we should have tests with PR asking changes
15:55:52 <cyril> ... because it will speed up CR processing
15:56:03 <cyril> pal: and helps people testing their implementation
15:56:41 <cyril> nigel: I'm hearing consensus to approve it and write tests for it
15:56:58 <cyril> pal: please include a test before merging the PR
15:57:03 <cyril> nigel: yes, good rule
15:57:26 <cyril> glenn: tests are not in the same repo
15:57:30 <cyril> pal: we could link PRs
15:57:39 <cyril> glenn: I have no problem creating tests for these
15:58:24 <cyril> RESOLUTION: we approve the PR and write tests for it
15:58:45 <cyril> Topic: TPAC Planning
15:59:06 <cyril> nigel: in the past, our team contact had prepared a wiki page
15:59:15 <cyril> ... with draft agenda topics
15:59:37 <cyril> ... there is also a proposal to have a joint meeting with CSS WG
15:59:47 <cyril> ... and there is an issue on the TTWG repo #52
15:59:54 <nigel> -> https://github.com/w3c/ttwg/issues/52 Discussion points for CSS WG at TPAC 2019
16:00:03 <cyril> ... gathering discussion points for CSS WG at TPAC 2019
16:00:17 <cyril> ... Atsushi could you create a similar looking wiki page
16:00:30 <cyril> atsushi: we should have a page for last year
16:00:55 <cyril> ... is it ok to do something like that?
16:00:57 <cyril> nigel: yes
16:01:32 <atsushi> 2018 -> https://www.w3.org/wiki/TimedText/tpac2018
16:01:33 <nigel> -> https://github.com/w3c/ttwg/issues/58 Action for Atushi to Create a TPAC 2019 wiki page
16:01:38 <cyril> pal: I'll be there only tuesday to thursday
16:01:51 <cyril> nigel: I'm not here next week
16:02:14 <cyril> ... unless someone wants to chair, i'll cancel next week
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16:03:12 <nigel> rrsagent, make minutes
16:03:12 <RRSAgent> I have made the request to generate https://www.w3.org/2019/07/18-tt-minutes.html nigel
16:11:54 <nigel> log: https://www.w3.org/2019/07/18-tt-irc
16:12:00 <nigel> Regrets: none
16:12:04 <nigel> rrsagent, make minutes
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16:16:03 <nigel> scribeOptions: -final -noEmbedDiagnostics
16:16:06 <nigel> rrsagent, make minutes v2
16:16:06 <RRSAgent> I have made the request to generate https://www.w3.org/2019/07/18-tt-minutes.html nigel
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