Dec 24 08:32:16 <witchymary> >The following headers do not affecting rendering, but can be used to record metadata about the script:
Dec 24 08:32:33 <witchymary> can i add any arbitrary headers there or it _must_ be the ones listed?
Dec 24 13:50:06 <Chortos-2> witchymary: you can physically add any number of arbitrary headers to ASS. neither the ones listed on the wiki page under "Informational Headers" nor any others you come up with yourself have any effect on renderers, and (de)muxing with MKVToolnix, FFmpeg etc. generally preserves all of them verbatim. but Aegisub has special UI for the ones listed, and Aegisub may or may not remove unrecognized headers
Dec 24 13:50:20 <Chortos-2> (by which I mean I think it does, but I'm not sure)
Dec 24 19:02:48 <Oneric> > Informational Headers
Dec 24 19:02:48 <Oneric> witchymary, Chortos-2: current Aegisub preserves all headers, yep (we looked into this e.g. for LayoutRes before). Hopefully muxers do as well.
Dec 24 19:02:48 <Oneric> So in practice there probably is no problem with any superfluent headers (see also e.g. old Aegisub dumping its metadata directly into [Script Info] as mentioned)
Dec 24 19:02:48 <Oneric> Since the mentioned ones are widely known (they come from SSA and today’s Aegisub menu), anything which actually makes metadata accessible will know about them, making them a tad more preferable
Dec 24 19:02:48 <Oneric> But what made me wary of just explicitly allowing all not-listed header names as free-for-all metadata fields, is that this would technically disallow any further extension of actually meaningful headers
Dec 24 19:02:50 <Oneric> Are there maybe some prefix ("Meta", "Author", ..) or so which these guidelines could explicitly allow to create custom metadata fields?
Dec 24 19:02:52 <Oneric> (future extensions can then just avoid this namespace and whatever wnats to expose metadata can search for all matches)

Dec 25 16:57:29 <Oneric> witchymary, Chortos-2: coming back to metadata headers, is there a prefix which would work well as a recommended way to generate custom metadata headers? E.g. just "Meta …"?
Dec 25 17:09:57 <Oneric> or maybe a set of prefixes reserved for custom metadata, if that works better?
Dec 25 17:19:48 <Chortos-2> personally, I don't see a need for one; you can just add a comment line prefixed by a semicolon or something
Dec 25 17:19:56 <Chortos-2> if no software is gonna parse the header anyway
Dec 25 17:21:33 <Oneric> hmm, I think Aegisub strips other ;-lines on saving though
Dec 25 17:22:37 <Oneric> if we want to distinguish "generated by" comments from other generic comments SSA’s !: could be reused, not sure how AEegisub deals with those though
Dec 25 17:23:55 <Oneric> Actually, let me try what happens. Plain !: or !CustomHeader: should make a decently non-intruisive header and definitely never overlap with future extensions
Dec 25 17:28:48 <Oneric> yep, Aegisub deletes any `;` lines but preservers both !: and !Header: lines, great
Dec 25 17:29:21 <Oneric> witchymary: does using a !: prefix for your custom metadata work for you?
Dec 25 17:40:34 <Chortos-2> or just stick to using a Comment: line timed at 0:00:00:00, which has the added bonus of showing up in Aegisub
Dec 25 17:41:08 <Chortos-2> in all honesty I can't imagine witchymary accidentally using a custom header for credits and that same header name later becoming standard and rendering-affecting
Dec 25 17:41:37 <Chortos-2> ...er, not-accidentally using it but accidentally setting the same name that later becomes standard
Dec 25 17:50:10 <Chortos-2> oh, speaking of which
Dec 25 17:50:16 <Chortos-2> none of the standard headers have spaces in their names
Dec 25 17:50:36 <Chortos-2> oh, YCbCr Matrix does
Dec 25 17:50:44 <Chortos-2> oh well