MPEG-4 TTXT with VLC/Quicktime

[Elias]

So I've muxed srt subtitle tracks with MP4Box and in VLC, it says tx3g (that's correct, right?), and well, with the latest nightly build of VLC (vlc-win32-200503220324.zip) it is possible to choose the ttxt track, but it's not showing up any subtitles. In quicktime 6.5.2 it doesn't even show up any subtitles, not even when I try to convert to 3G and encode the subtitle track to 3GPP Timed Text (which is if I've understood it right, the exact same thing as MPEG-4 Timed Text). So, my question is: how do I know that this MPEG-4 subtitle thing works as it should? I mean, if it's stable, then is it safe to encode movies with such subtitles and just let the encodes hang there until any player supports them? On Wikipedia, it says that the MPEG-4 Subtitle format isn't finished:

"Part 17 (ISO/IEC 14496-17): Timed Text subtitle format (not yet finished - reached "FCD" stage in January 2005)."

What's up with this? Check it yourself: http://en.wikipedia.org/wiki/MPEG-4

[ac-chan123]

Part 17 of MPEG4 is mostly the same as the timed Text in 3gpp. Look at the "3GPP TS 26.245" Specification. You can find them at http://www.3gpp.org/ftp/Specs/html-info/26245.htm.

It is better not to search Wikipedia for MPEG thinks. Search at JTC1 SC29 WG11 own site http://www.itscj.ipsj.or.jp/sc29/ or at Leonardo Chiariglione Site http://www.chiariglione.org/mpeg/. Also refer to the informations by bond in this Forum.
MPEG-4 Information (http://forum.doom9.org/showthread.php?s=&threadid=73022) | MP4 FAQ (http://forum.doom9.org/showthread.php?s=&threadid=62723)| AVC/H.264 FAQ (http://forum.doom9.org/showthread.php?s=&threadid=73022#post461589) | AAC FAQ (http://forum.doom9.org/showthread.php?s=&threadid=68300#post424070)

[Elias]

Originally posted by ac-chan123
Part 17 of MPEG4 is mostly the same as the timed Text in 3gpp. Look at the "3GPP TS 26.245" Specification. You can find them at http://www.3gpp.org/ftp/Specs/html-info/26245.htm.

It is better not to search Wikipedia for MPEG thinks. Search at JTC1 SC29 WG11 own site http://www.itscj.ipsj.or.jp/sc29/ or at Leonardo Chiariglione Site http://www.chiariglione.org/mpeg/. Also refer to the FAQ by bond in this Forum. Well I just write some stuff on Wikipedia, and when I was editing the MPEG-4 article, I noticed that some dude had written that it wasn't complete, so I changed it to complete since bond said that it was, and he knows a lot about MPEG-4 but then some dude changed it back to incomplete and insisted that it wasn't complete. I'm confused because of that.

[ac-chan123]

He is right. It is in FCD(Final Comittee Draft). Because this Standart only refer to a 3GPP Spezification so you can see it as complete.
The FCD Voting run to 2005 june 17. If nothing go wrong a short time later it is a standard.

[Elias]

Originally posted by ac-chan123
He is right. It is in FCD(Final Comittee Draft). Because this Standart only refer to a 3GPP Spezification so you can see it as complete.
The FCD Voting run to 2005 june 17. If nothing go wrong a short time later it is a standard. So let me get this straight, MPEG-4 Timed Text is complete, but 3GPP Timed Text is in FCD voting? How come in Quicktime it's possible to convert text into 3GP Timed Text but not MPEG-4 Timed Text?

[ac-chan123]

ISO/IEC 14496-17 is in FCD voting.
3GPP TS 26 245 is already spezified and in use.

[Elias]

Originally posted by ac-chan123
ISO/IEC 14496-17 is in FCD voting.
3GPP TS 26 245 is already spezified and in use. Does this mean that I can safely convert srt with MP4Box into ttxt or do I have to wait until MPEG-4 ttxt becomes fully complete?

[ac-chan123]

It is complete. The FCD is for a final check befor it is a standard. Mostly the writing(spell and this linke) will be changed. In this state should all be fine. Mostly only the "Cover" will be replace with the ISO one.

[Elias]

Originally posted by ac-chan123
It is complete. The FCD is for a final check befor it is a standard. Mostly the writing(spell and this linke) will be changed. In this state should all be fine. Mostly only the "Cover" will be replace with the ISO one. So MPEG-4 Timed Text is safe for use as of right now with MP4Box *.srt--->*.ttxt? I'm just checking since I want to be on the safe side.

[ac-chan123]

not 100% but > 95%

[Elias]

Originally posted by ac-chan123
not 100% but > 95% Darn :/ Well I guess this is why mediainfo doesn't recognize any ttxt files, nor quicktime, and possibly this could be the reason why they aren't working in VLC but only in Osmo4?

[bond]

Originally posted by ac-chan123
He is right. It is in FCD(Final Comittee Draft). Because this Standart only refer to a 3GPP Spezification so you can see it as complete.elias, read ac-chan123's words, its as good as final, normally there arent any changes on the "final comittee draft" anymore which change the format
and you wouldnt want to know how many people develop following the freely available "final comittee drafts" of other mpeg-4 standards without a problem and without ever looking at the real official version (which has to be bought from iso) :D

Originally posted by Elias
So I've muxed srt subtitle tracks with MP4Box and in VLC, it says tx3g (that's correct, right?)yes

and well, with the latest nightly build of VLC (vlc-win32-200503220324.zip) it is possible to choose the ttxt track, but it's not showing up any subtitles.thats the same i get
vlc's ttxt handling is broken

In quicktime 6.5.2 it doesn't even show up any subtitles, not even when I try to convert to 3G and encode the subtitle track to 3GPP Timed Text (which is if I've understood it right, the exact same thing as MPEG-4 Timed Text).indeed, qt ignores timed text streams in .mp4, altough i assume it could be easily changed to support it (text renderer aso already existing)

So, my question is: how do I know that this MPEG-4 subtitle thing works as it should? I mean, if it's stable, then is it safe to encode movies with such subtitles and just let the encodes hang there until any player supports them?play your samples in realplayer
ok it has to be said that the publically available realplayer has some quirks, like it doesnt seem to support the placement of text over the video till now, doesnt display any subs when the first subsample isnt starting at 00:00:00.000 and doesnt display any subs when there is an empty subsample in the stream :rolleyes:

i already contacted the real devs about that and they are planning to fix that

apart from these issues mp4box created timed text .mp4 files play fine in realplayer

[Elias]

Originally posted by bond
thats the same i get
vlc's ttxt handling is brokenYou possibly don't know when it'll be fixed?

Originally posted by bond
indeed, qt ignores timed text streams in .mp4, altough i assume it could be easily changed to support it (text renderer aso already existing)How?

Originally posted by bond
play your samples in realplayer
ok it has to be said that the publically available realplayer has some quirks, like it doesnt seem to support the placement of text over the video till now, doesnt display any subs when the first subsample isnt starting at 00:00:00.000 and doesnt display any subs when there is an empty subsample in the stream :rolleyes:I don't know man, I really really hate RealPlayer. I have to do a clean install of XP every time after I've uninstalled it, just to be on the safe side because I don't trust those assholes at real since well, they add bunch of spyware etc. Will it work with Real Alternative in MPC? The latest version that is.

Originally posted by bond
i already contacted the real devs about that and they are planning to fix thatGreat :D

Originally posted by bond
apart from these issues mp4box created timed text .mp4 files play fine in realplayer So I guess this means that the ttxt created by mp4box are 100% MPEG-4 ISO/IEC compliant and should be b0rk-free when better players like VLC/MPC will support them? By the way, since we're speaking of VLC and *.mp4, could you contact some VLC devs about VLC's inability to recognize 6 channel (or 5.1) MPEG-4 AAC in *.mp4? For some reason, if the 5.1 LC AAC track is in a *.mov container, it recognizes it as a 6 channel track, but not in *.mp4... why?

[bond]

Originally posted by Elias
[B]You possibly don't know when it'll be fixed? indeed

Will it work with Real Alternative in MPC? The latest version that is. nope

By the way, since we're speaking of VLC and *.mp4, could you contact some VLC devs about VLC's inability to recognize 6 channel (or 5.1) MPEG-4 AAC in *.mp4? For some reason, if the 5.1 LC AAC track is in a *.mov container, it recognizes it as a 6 channel track, but not in *.mp4... whyno clue about that

[Elias]

http://developer.apple.com/documentation/QuickTime/QT6_3/QT6_3WhatsNew.pdf I think this might be of interest :)
http://developer.apple.com/documentation/QuickTime/QT6_3/index.html Or this if you prefer it in html :)

[bond]

Originally posted by Elias
http://developer.apple.com/documentation/QuickTime/QT6_3/QT6_3WhatsNew.pdf I think this might be of interest :)
http://developer.apple.com/documentation/QuickTime/QT6_3/index.html Or this if you prefer it in html :) i pointed jeanlf from gpac to this and mp4box now supports importing such qt .xml representations for timed text :)

mp4box will not support exporting it tough, as jean meant its not really well designed as it repeats the text sample description for each sample (altough you only need it once), which makes it really unsuitable for large streams as its bloated

[Elias]

Originally posted by bond
i pointed jeanlf from gpac to this and mp4box now supports importing such qt .xml representations for timed text :)

mp4box will not support exporting it tough, as jean meant its not really well designed as it repeats the text sample description for each sample (altough you only need it once), which makes it really unsuitable for large streams as its bloated Great! So does this mean that we can now convert srt into ttxt that are fully MPEG-4 ISO compliant and play them in QT? Where's the latest MP4Box that can handle this? By the way, I've learned commandlines :D

[bond]

Originally posted by Elias
[B]Great! So does this mean that we can now convert srt into ttxt that are fully MPEG-4 ISO compliantthey have always been compliant ;)

and play them in QT? Where's the latest MP4Box that can handle this? By the way, I've learned commandlines :Dyou can find it on celticdruids site
qt will only handle ttxt in .3gp, so you have to convert your .mp4 file to .3gp or output directly .3gp files (eg with mp4box itself)

i have contacted a qt dev and they consider adding ttxt support to their .mp4 parser, after all it shouldnt be hard, as its the same in both formats

[Elias]

Originally posted by bond
they have always been compliant ;)Not if they don't play/work ;)

Originally posted by bond
you can find it on celticdruids site
qt will only handle ttxt in .3gp, so you have to convert your .mp4 file to .3gp or output directly .3gp files (eg with mp4box itself)

i have contacted a qt dev and they consider adding ttxt support to their .mp4 parser, after all it shouldnt be hard, as its the same in both formats Thanks! So does this mean that if I create an *.mp4 with ttxt now in MP4Box they will work in future versions of QT?

[bond]

Originally posted by Elias
Not if they don't play/work ;)well, if qt is borky it doesnt mean its the problem of mp4box ;)

Thanks! So does this mean that if I create an *.mp4 with ttxt now in MP4Box they will work in future versions of QT?no, it means that they will consider supporting it :D

[Elias]

Originally posted by bond
no, it means that they will consider supporting it :D Hehe yeah, but IF they EVER supported it, clear enough for you? :D

[Elias]

By the way, bond, do you know when VLC will be able to play tx3g subtitles? You seem to have contact with the VLC team, so you know anything about this? I guess they're working on it now, but like an estimation of how long it will take until the nightly builds will be able to play 3GPP Timed Text would be nice :)

[Elias]

Originally posted by Elias
and well, with the latest nightly build of VLC (vlc-win32-200503220324.zip) it is possible to choose the ttxt track, but it's not showing up any subtitles.All right, with the latest VLC Nightly Build (vlc-win32-200503310325.zip) I get this message when I look in messages: "main error: no suitable decoder module for fourcc `tx3g'.
VLC probably does not support this sound or video format." I use the latest MP4Box and the 3GPP Timed Text track works great in Quicktime. VLC DEFINITELY has issues here.

[Elias]

Why does the files become a couple of seconds longer with 3GPP Timed Text? In Quicktime and VLC, they're a couple of seconds longer, but not in MPC. And no, the subtitle time does not over ride the video/audio length.

[bond]

nope, i dont think anyone is working on ttxt in vlc, you might want to ask fenrir when/if he will fix it

about the time issue, no clue, you might want to ask jeanlf from gpac

[Elias]

thats the same i get
vlc's ttxt handling is brokenI've discussed this on the VLC forum (http://forum.videolan.org/viewtopic.php?p=36312), and they're hopefully working on MPEG-4 Timed Text (https://trac.videolan.org/vlc/ticket/332) support soon.