EPUB 3 Working Group Telco — Minutes

Date: 2022-03-25

See also the Agenda and the IRC Log


Present: Ivan Herman, Avneesh Singh, Laura Brady, Masakazu Kitahara, Wendy Reid, Rick Johnson, Dave Cramer, Gregorio Pellegrino, Matthew Chan, George Kerscher, Dan Lazin, Deborah Kaplan, GeorgeK, Brady Duga, Zheng Xu (徐征), Jen Goulden, Charles LaPierre, Bill Kasdorf, Ben Schroeter, Matt Garrish, Tzviya Siegman

Regrets: Toshiaki Koike


Chair: Dave Cramer

Scribe(s): Matthew Chan


1. Tolerance margin for the sum of MO durations? (issue epub-specs#2093)

See github issue epub-specs#2093.

See github pull request epub-specs#2106.

Dave Cramer: we say the sum of the duration for each MO document should equal the total duration, but we’ve never specified a margin or tolerance for this.
… suggestion was that perhaps we should do so?.
… the suggestion was to allow 1 sec of tolerance before epubcheck would complain, to account for rounding errors.

Avneesh Singh: I think this is not controversial.

Ivan Herman: what I learned when I made tests, is that this value which is in the manifest is there to check the data.
… marissa has even suggested that this is unnecessary.

Ivan Herman: I can’t say whether or not that is so, but if it is just for checking purposes, then allowing some rounding error is fine.
… not sure what the actual threshold should be, so for now I think 1 second is fine.

Zheng Xu (徐征): from what i’ve implemented, the duration is variable for different players on different platforms.
… so i wonder if this is even useful.

Avneesh Singh: regarding 1 second, i feel this is more than enough. Maximum 50 ms is what i’ve used in the past.
… for large audios (120 hours), a tolerance of 150 ms was enough.
… per my understanding, the purpose of stating this metadata is to allow RS to pull a “total duration” value into features like “you are 5 minutes into 12 total hours”.

Brady Duga: can epubcheck just tell you the total duration value that should be in the manifest?.
… epubcheck can give you the right value, right?.

Matt Garrish: epubcheck is checking the total time, yes. I guess it could output that value..

GeorgeK: my recollection is that its difficult to calculate some of these things precisely, depending upon the compression that is being used, resulting in it being off by a smidgen in each file.
… so this type of tolerance seems absolutely fine, 1 second seems fine.

Ivan Herman: +1 to George.

Zheng Xu (徐征): as a RS I appreciate having the duration values for the whole book, and for each file.
… we use it as an indication of approximately where the user is, but it doesn’t have to be that accurate.

Dave Cramer: i’m not hearing an argument against the 1 sec tolerance.
… it’s obviously a useful piece of metadata for people reading the book.
… and having epubcheck able to tell if the sum = total is useful authoring tool, with 1 second tolerance.

Zheng Xu (徐征): +1.

Ivan Herman: +1.

Proposed resolution: Merge PR 2106, close issue 2093. (Wendy Reid)

Dave Cramer: +1.

Matt Garrish: +1.

Matthew Chan: +1.

Brady Duga: +1.

Masakazu Kitahara: +1.

Wendy Reid: +1.

Laura Brady: +1.

Avneesh Singh: +1.

Bill Kasdorf: +1.

Ivan Herman: +1.

GeorgeK: +1.

Zheng Xu (徐征): +1.

Ben Schroeter: +1.

Resolution #1: Merge PR 2106, close issue 2093.

Rick Johnson: +1.

2. Scripted SVG (issue epub-specs#2098)

See github issue epub-specs#2098.

Dave Cramer: we can have scripted Top Level Content document, and scripted svg in iframe is container-constrained, but what about other cases?.

Matt Garrish: so is scripted svg valid? And what about RS support for scripting? Are we saying you can put scripted SVG anywhere, but it might not be supported?.

Dave Cramer: has anyone here ever put scripted SVG into an epub?.

Brady Duga: it’s a weird question, because its scripting, so it’s already not guaranteed to work.
… the real question is do we explicitly make it illegal in some cases.
… i’m not sure why we would need to because there are already no guarantees when it comes to scripting, seems like an edge case we don’t need to spend that much time on.

Dave Cramer: i presume there have not been epubcheck bugs specifically about this?.

Matt Garrish: no, it’s valid, so we don’t say you can’t do it. But this doesn’t fall into container-constrained.

Ivan Herman: we should say yes it’s allowed, and we should write some tests for it.
… i’ve already done some tests of svg, and i’ve tried putting svg in iframe.
… if testing reveals lack of support, then we will deal with that.
… but I wouldn’t make it invalid.
… i think there is a big difference in HTML whether you use svg as object or in img tag.
… not sure if scripted svg will work in img tag even in HTML.

Matt Garrish: no, scripting won’t work in img tag.
… just strange to say that the container-constrained ones must be done in iframe (not object).
… any reason why we can’t add object to container-constrained?.
… what is container-constrained stopping?.

Brady Duga: i think container-constrained was meant to make is to that the element wouldn’t change its size, that it wouldn’t interact with the DOM, or break anything else.
… but you don’t really get that with object.

Ivan Herman: so, as of right now, using object is illegal?.

Brady Duga: it’s fine, it just doesn’t count as container-constrained.
… it means that the content document would be scripted, instead of scripting being limited to the element.

Matt Garrish: we say you should support container-constrained scripting, but may support scripting in the content document.

Dave Cramer: i found the part of HTML spec that says you can’t have scripted svg in img.
… (it also says support for svg is not required for HTML spec).

Ivan Herman: okay, so what’s the resolution?.

Dave Cramer: we wait to see what tests tell us?.

Ivan Herman: if we are responding to a specific question (as it says in issue) then we should make an editorial comment.

Matt Garrish: we can mention that object does not count as container constrained.

Brady Duga: it sounds like a good idea to add clarifying text, but is there something in our spec that makes people believe that putting something in an object tag would make something container-constrained?.

Matt Garrish: content document is silent on whether or not it is valid to put scripted svg in object, you’d need to go to RS spec to see that.

Brady Duga: i’m fine with making people who want to use scripting in epub read RS spec.

Ivan Herman: my position is that a real question came up, so that means the core spec isn’t clear enough. We should do something about that..
… let’s not make a big deal about it.

Zheng Xu (徐征): what does the RS need to do beyond a normal web browser?.
… regarding scripted svg.

Dave Cramer: i don’t think there’s anything.
… our basic idea is to make it easier for RS, to think of ways to allow some scripting that doesn’t blow up the entire layout of the book.

Ivan Herman: only minor thing is that an svg file should have access to the epubreadingsystem object.

Zheng Xu (徐征): in terms of bad usage of svg scripting, I don’t know how to avoid this.

Ivan Herman: as soon as we allow scripting, we can no longer prevent users from shooting themselves in the foot with it.

Proposed resolution: Add note about container constraints to scripting section, close issue 2098. (Wendy Reid)

Dave Cramer: +1.

Ivan Herman: +1.

Tzviya Siegman: +1.

Matthew Chan: +1.

Rick Johnson: +1.

Charles LaPierre: +1.

Matt Garrish: +1.

Wendy Reid: +1.

Ben Schroeter: +1.

Masakazu Kitahara: +1.

Bill Kasdorf: +1.

Laura Brady: +1.

Brady Duga: 0.

Zheng Xu (徐征): 0.

Resolution #2: Add note about container constraints to scripting section, close issue 2098.

3. Separate collection authoring from specialization requirements (pr epub-specs#2060)

See github pull request epub-specs#2060.

Ivan Herman: See Diff file for the PR.

Matt Garrish: in reviewing this part of authoring spec, found that this was defining how to create collections.
… initially what I did was take user requirements about how to create these collections and moved them into a separate subsection.
… from there ivan and I discussed, and the question was that if we’re not using collections anymore (and even the ones that have been authors have not met with huge uptake) can we deprecate the authoring of new collection elements?.
… then we wouldn’t need to have all these weird requirements about authoring new collections.
… we already had a note saying that we had no intention of continuing these, so is it okay to officially deprecate the authoring of new collections?.

Dave Cramer: but we keep the existing ones.

Matt Garrish: yes, anything already created stay valid, there will not be issues with epubcheck.
… but you should not be creating new collection roles.

Tzviya Siegman: reading back into history of collections, I’m very much in agreement that this should be removed.
… we were optimistic, but real world implementation was never a certain thing.

Matt Garrish: the whole collection element was complicated, cases of collections within collections, complications to spine, etc..
… i just want to make it clearer than the note that we’re not moving towards this in the future.

Wendy Reid: i don’t think i’ve ever seen this in the real world.

Dave Cramer: did the index spec refer to this?.

Matt Garrish: there are a lot of specs that refer to collections, but they were just never really authored.

Proposed resolution: Merge PR 2060, deprecate collections. (Wendy Reid)

Matt Garrish: and anything that did rely on this would still be valid.

Matt Garrish: +1111111111111111.

Charles LaPierre: +1.

Ivan Herman: +1.

Wendy Reid: +1.

Rick Johnson: +1.

Tzviya Siegman: +1.

Dan Lazin: +1.

Ben Schroeter: +1.

Masakazu Kitahara: +1.

Matthew Chan: +1.

Laura Brady: +1.

Bill Kasdorf: +1.

Dave Cramer: +1.

Zheng Xu (徐征): +1.

Resolution #3: Merge PR 2060, deprecate collections.

4. Volunteers for review.

Dave Cramer: See spreadsheet for reviewers.

Dave Cramer: we are getting closer to CR, and as part of that we need more eyes on the spec.
… to make sure that things make sense, that we haven’t missed anything obvious.
… we are looking for volunteers for this, and the signup sheet is linked above.
… volunteer now while you can still have your choice of which section to review.

Brady Duga: i asked this earlier but, what’s the timing for this? I will be gone for 2 weeks starting morning. I’m part way through what i’ve already signed up for, but not sure if I should claim more sections.

Wendy Reid: please finish before you leave.
… some sections are very very short, btw.
… you don’t need to be an expert on this. Just make sure the language is clear, that it makes sense, that it is readable and coherent.
… you can also flag grammar issues.

Matt Garrish: I start to expect what is there, rather than reading it with fresh eyes.

Brady Duga: so, the deadline?.

Ivan Herman: the CR means that the group feels that all technical issues are solved. So in essence, editorial things can still change later, after it is in CR. But it is more complicated if we find technical problems requiring changes to normative text later.
… duga if you can look at those sections where they may be technical issues, that would be helpful.
… editorial things can be done later.
… the point is, per charter, we are already late for CR. We should really aim for going to director for approval for mid-April.
… there are already a lot of PRs in queue, but most of those are editorial.
… wonderful if you could complete your reviews by the end of the week, but that may be too much to ask.

Brady Duga: this is for everyone. Understanding the urgency is helpful, thank you..
… i have a couple of changes (typos, minor edits), so I shouldn’t spend time turning those into PR right now, I’ll focus on technical things for now.
… those editorial ones can wait for later in April, and so on.

Tzviya Siegman: I would suggest that we go to CG for some more volunteers.

Dave Cramer: it’s been filling up noticeably.

Ben Schroeter: what if we come across something we’d like to change?.

Ivan Herman: yes, we have a bunch of PRs, and you all incur the danger of looking at a version that may be altered via an in queue PR.
… there is one PR that mgarrish is very busy with that will have impact on quite a number of areas.
… PR #2101.
… diffs are too many to display in Github UI.
… it is creative chaos.

Wendy Reid: thank you everyone, the list is almost full!.

Tzviya Siegman: do you really want that many PRs? Won’t you end up with merge conflicts?.

Matt Garrish: so long as people are working in separate areas it shouldn’t be that bad.

Dave Cramer: okay, thank you everyone for a productive meeting.
… go forth and review.
… we will see you all next week.

5. Resolutions