13:59:58 RRSAgent has joined #tt 13:59:58 logging to http://www.w3.org/2017/03/30-tt-irc 14:00:00 RRSAgent, make logs public 14:00:00 Zakim has joined #tt 14:00:02 Zakim, this will be TTML 14:00:02 ok, trackbot 14:00:03 Meeting: Timed Text Working Group Teleconference 14:00:03 Date: 30 March 2017 14:00:15 Present: Nigel 14:00:18 scribe: nigel 14:00:21 Chair: Nigel 14:00:25 Regrets: Pierre, Dae 14:02:40 Present+ Glenn 14:04:07 Present+ Thierry 14:05:34 Present+ Andreas 14:06:00 Topic: This Meeting 14:06:36 Nigel: For today we have some updates on IMSC and some TTML issues. Any other business? 14:06:43 group: [no other business] 14:07:18 Nigel: Next week I will not be available, and nobody has offered to Chair. Any volunteers? 14:07:25 Andreas: I may also not be able to attend next week. 14:08:04 Nigel: If anyone does want to Chair next week's meeting please let me know by Tuesday 14:08:17 .. at the latest and I will be able to assist with any queries etc. 14:08:27 .. Otherwise the default position may be that we do not hold a meeting. 14:09:00 atai has joined #tt 14:09:06 Topic: IMSC 14:09:29 Nigel: My update is that after publishing the WD for Wide Review Thierry sent the horizontal 14:09:54 .. review and internal dependency review messages out to other W3 groups. 14:10:15 Thierry: I have sent the questionnaire to the group and that is holding back the request to 14:10:23 .. TAG. That's the only one that is pending. 14:10:42 Nigel: Thank you. And I sent all the external liaisons. It turns out that DLNA is no longer 14:11:11 .. operating, so I could not send to them. I got several responses back from people saying 14:11:19 .. they had received it and would provide feedback. 14:12:25 Nigel: Thierry sent that questionnaire out on 24th March. Any queries on that now? 14:13:01 Thierry: I reused the wording from TTML. Probably what may be missing is stuff about the 14:13:20 .. use of images in IMSC1. 14:13:32 Nigel: I see that the answer to 3.6 needs editing to remove audio and condition for example. 14:14:16 Thierry: Ok 14:14:25 Nigel: If you make those edits then we can approve the updated text by email. I think the 14:14:33 .. remaining responses are uncontroversial. 14:14:40 Thierry: I will do that right now. 14:15:00 Nigel: We had one issue raised on IMSC this week that is of some interest: 14:15:06 -> https://github.com/w3c/imsc/issues/224 14:15:46 Nigel: This is about whitespace handling. 14:16:04 Glenn: The issue here is that the wording of XSL-FO makes it hard for me to determine if 14:16:25 .. the intent is to fully translate all whitespace that is XML whitespace into 0x20 space characters. 14:16:58 Nigel: I had the same issue, I wasn't sure exactly what it was trying to say or if there is some 14:17:04 .. order of precedence in applying the various rules. 14:17:20 Glenn: The problematic part is whether or not collapse semantics apply, and it seems like 14:17:35 .. you can read it that for the first character in a sequence of whitespace, if it is not a space, 14:17:48 .. then you might not collapse it. I do not think that is the intent and I do not know of any 14:18:01 .. implementation that does not translate tab in that context into space, so I think implementations 14:19:01 .. should collapse it. 14:19:20 Nigel: I think my colleague Chris (who raised the issue) has an implementation that seems 14:19:28 tm has joined #tt 14:19:35 .. to have this behaviour of retaining the first tab, and seems to obey the letter of the 14:19:39 .. specification rather than the intent. 14:19:55 Glenn: I think the Antenna House and FOP implementations do it differently, so the question 14:20:07 .. is I guess what we really want to happen. If we want that tab to be normalised to space 14:20:21 .. then we need to fix up our spec. My suggestion is to add language to TTML1 and TTML2 14:20:38 .. to have that effect. Even if we do not translate it into space there is certainly no suggestion 14:20:54 .. that it be translated into an alignment or some spaces. 14:21:24 Nigel: Even if no alignment and no spaces a tab would be expected to have some inline width. 14:21:41 Glenn: Usually a tab character is not in a font and is mapped to zero width. It has no 14:21:49 .. inherent width semantics. 14:22:13 Probably any fonts that do have a tab character map it to zero width or to the space glyph. 14:22:25 Andreas: I have a question regarding Chris's original question. He asked on the basis of 14:22:32 .. Example 7 of IMSC 1.0.1? 14:22:34 Nigel: Yes. 14:23:13 Andreas: So actually we did not provide the source for the example? 14:23:17 Nigel: Yes, we do. 14:24:01 .. The way the spec is structured the example is an XML document that is imported by the 14:24:10 .. HTML and then formatted. So the tabs are really there. 14:24:15 Glenn: We should fix the example. 14:24:26 -> https://www.w3.org/TR/ttml-imsc1.0.1/#itts-fillLineGap 14:24:45 Nigel: Yes I agree and Pierre has indicated he agrees with that, on the issue. 14:25:05 glenn has joined #tt 14:25:09 rrsagent, make minutes 14:25:09 I have made the request to generate http://www.w3.org/2017/03/30-tt-minutes.html nigel 14:26:16 Glenn: I agree with Andreas however, that said, I think we should remove the tabs. 14:29:34 Glenn: There's another property called whitespace-treatment ... 14:29:43 Nigel: There are 4 properties defined by TTML1: 14:29:44 -> https://www.w3.org/TR/ttml1/#content-attribute-space 14:30:33 Glenn: If you look at §7.16.8 in XSL 1.1 on whitespace treatment: 14:31:22 https://www.w3.org/TR/xsl/#white-space-treatment 14:31:32 s/http/-> http 14:35:49 Nigel: Since we use suppress-at-line-break=auto that means only U+0020 is suppressed, 14:35:53 .. and everything else is retained. 14:36:16 Glenn: Correct. 14:36:39 .. Under §1.2.1 under paging and scrolling it talks about splitting things like whitespace 14:36:53 .. into separate properties for greater control. The intent was to derive those properties 14:37:10 .. from CSS2, in this case the CSS2 property called "whitespace". So to follow the implementation 14:37:23 .. path of other implementations we probably want to go and look at CSS2 whitespace. 14:37:38 https://www.w3.org/TR/REC-CSS2/cover.html#minitoc 14:38:02 s/http/-> http 14:38:24 Glenn: The initial value of whitespace is "normal" which directs user agents to 14:38:32 .. "collapse sequences of whitespace, and break lines as necessary to fill line boxes" 14:39:20 .. and does not make a distinction between different kinds of whitespace. 14:39:41 Nigel: If you follow the link it defines whitespace as: 14:39:46 -> "Only the characters "space" (Unicode code 32), "tab" (9), "line feed" (10), "carriage return" (13), and "form feed" (12) can occur in whitespace. " 14:40:10 Glenn: Exactly. These are the same as XML whitespace. It looks like there's a bug in XSL-FO here. 14:40:23 .. I wonder if this was updated in a later version of XSL-FO. 14:40:33 .. Perhaps Steve Zilles would be a good person to ask about this. 14:41:01 Andreas: I think we could also contact Tony Graham who is at Antenna House. 14:41:31 Glenn: We should certainly contact Steve as he is still active in W3C whereas Tony is not. 14:43:07 Nigel: Which should we do first, contact Steve or create the issues on TTML? 14:43:17 Glenn: I will create the issues and link them to the IMSC issue from Chris and articulate 14:43:29 .. the problem as I see it and then we can use that as reference material in an email to 14:43:33 .. Steve and Tony. 14:44:02 Glenn: I know both Steve and Tony so I can ask them. Since I chair the Apache group on FOP 14:44:05 .. I have a link there too. 14:44:35 Nigel: Okay, that's a plan, thank you. 14:45:07 .. I will add a note to the issue. 14:47:07 -> https://github.com/w3c/imsc/issues/224#issuecomment-290434056 14:48:26 Topic: TTML 14:49:54 -> https://github.com/w3c/ttml2/issues/233 14:50:07 Nigel: This raised some eyebrows, since there was already a pull request that Pierre had 14:50:11 .. opened on request. 14:51:00 Glenn: I always edit pull requests before applying them to add my imprimatur and make 14:51:03 .. sure they are consistent. 14:51:29 using PR is not 10 yeras of process ... 14:52:30 q+ 14:52:51 Nigel: From a process point of view, we had https://github.com/w3c/ttml2/pull/283 which 14:53:12 .. the Group requested from Pierre to resolve the issue he raised, which was closed without 14:53:27 .. any communication and it was not obvious why. The branch for the pull request could 14:53:52 .. easily have been modified in place rather than closing and opening a new one, which 14:54:04 .. would have been less work and would have made the provenance clearer. 14:54:35 Glenn: One thing here was that the branch was not properly named and had things in 14:55:09 .. which were not done in the right way. There was no intention to raise tensions. 14:55:12 ack atai 14:55:41 Andreas: This is an interesting discussion - things like GitHub have changed the way that 14:55:57 .. groups can collaborate on specification texts. I think we appreciate that the Editor here 14:56:20 .. has a different view maybe. We as a Group should decide on what the process is that 14:57:02 .. we use, and also recall that proposals and changes can be made onto the pull requests. 14:57:41 Nigel: By the way you can rename a branch if that is the issue. 14:57:53 Glenn: It is not so straightforward because the pull request doesn't get modified. It is okay 14:58:05 .. to do it locally before pushing to the remote, but when pushing to the remote things 14:58:08 .. get locked in. 14:58:22 Glenn: The only substantive point on this particular issue is the name. I've stated my opinion 14:58:50 .. on that. I don't think adding length to the name has any improvement. That's my opinion. 15:03:54 Nigel: The name needs to reflect the scope of application, which is much narrower than it 15:04:10 .. is specified at the moment, and appears to apply to all HDR content rather than 15:04:22 .. just those HDR schemes that require it. 15:04:43 .. This also needs to be reflected in the specification text, which likewise needs 15:05:34 .. to be narrowed to schemes such as PQ HDR. 15:05:49 Glenn: Looking at the original proposal, that referred to images, which I took out. 15:06:22 .. I took "image" to refer to the content on which it is composited rather than a referenced 15:06:35 .. PNG or JPEG image in an element. Is that not right? 15:07:09 Nigel: No that's correct I think it is about the video images, for example. 15:08:15 Glenn: Pierre used the term "target image" and I changed it to "target medium" - I found 15:08:22 .. ways to eliminate the use of "image". 15:09:25 .. The other thing is that the example has the unexplained value 2.4 so I added "where the 15:09:40 .. exponent of 2.4 is the gamma correction applied by the EOTF". I may have been wrong 15:09:45 .. in that but that was my interpretation. 15:10:50 .. Just below the syntax box there is an equation that uses the term "normalized" which 15:11:45 .. I assume meant application of the gamma of 2.4. 15:12:10 Nigel: That's the root of the problem - there is another scheme for HDR that does not use 15:12:40 .. the luminance gain approach at all but uses a different approach varying the gamma. 15:12:44 https://en.wikipedia.org/wiki/Gamma_correction 15:12:48 atai has left #tt 15:12:49 Andreas: I have to drop off now. Thank you. 15:13:11 Nigel: By specifying tts:luminance and using this kind of wording it looks as though we are 15:13:24 .. promoting one particular scheme for HDR, which is not what we should be doing at all. 15:13:38 Glenn: I was not aware of that context. 15:13:52 OK bye 15:15:02 Thierry: [drops off call] 15:16:05 Glenn: I did not make any other changes here. 15:16:26 .. Actually I did fix another change which was an error - he had an integer type but in the 15:16:46 .. examples used non-integer numbers so I changed to a non-negative real number. 15:17:06 .. I also added continuous animation support. Any numerical value I make continuous. 15:17:37 Nigel: By the way the other colour space that is often used is BT.2020 - we currently only 15:17:52 .. refer to BT2100 in Appendix P. So there needs to be some work here to make this 15:17:56 .. more neutral. 15:18:08 Glenn: Please note that people file new issues on the text rather than piling comments on 15:18:17 .. to the original issue. We can always point back to the original issue. 15:20:03 Nigel: Can I just check - are there other branches with work in progress on them that 15:20:11 .. are not yet complete and might be worth review? 15:20:27 Glenn: I have about 10, particularly Audio Description. I'm hoping we do not slide too far 15:20:36 .. beyond the end of the month. The other one that is higher up on my list is the one that 15:20:46 .. came up last week regarding Andreas's pull request on TTML1. 15:23:37 Nigel: I see that just Glenn and I remain on the call so we should probably close! 15:24:21 Glenn: I will take a look at Andreas's pull request and may need to make some changes to it. 15:24:39 Nigel: If you can edit the branch that is the source of the pull request that will be better. 15:24:49 .. Even if you commit directly to that branch. 15:24:55 Glenn: Okay I will give that a go. 15:25:05 Nigel: Ok thanks, see you in a couple of weeks. [adjourns meeting] 15:25:08 rrsagent, make minutes 15:25:08 I have made the request to generate http://www.w3.org/2017/03/30-tt-minutes.html nigel 15:30:49 s/Probably any fonts/.. Probably any fonts 15:43:39 rrsagent, make minutes 15:43:39 I have made the request to generate http://www.w3.org/2017/03/30-tt-minutes.html nigel 15:46:09 ScribeOptions: -final -noEmbedDiagnostics 15:46:10 rrsagent, make minutes 15:46:10 I have made the request to generate http://www.w3.org/2017/03/30-tt-minutes.html nigel 17:01:43 Zakim has left #tt