official MPEG-4 Subtitle/Text Stream format finalized (ISO 14496-17)

[bond]

In contrary to prior MPEG Standards (MPEG-1/2) MPEG-4 now has its own official subtitle/text stream format specified under ISO 14496-17

the specs seem to have been finalized in february 2004 ("Final Committee Draft of MPEG-4 streaming text format") till now it hasnt been officially approved but i guess thats only a matter of time and will not change the specs from the final draft (maybe someone knows more about how mpeg handles this?)

i have the following infos about the format:
- mpeg-4 subs can use UTF-8 or 16
- they will be stored as text, not encoded/compiled as binary like with bifs
- you can configure things like the position of the text within the picture
- its possible to scroll (horizontally and vertically)
- you can link subtitles with audio streams (like when someone switches from french to english audio, the french subs are displayed automatically too aso..)
- you can put urls in the subs
- it will be possible to attach fonts to the subs
- the subs will be stored as seperate streams, labelled as "mp4s" (video = mp4v, audio = mp4a)
- the subtitles can be maximal 10kbit/s
- the subs will be streamable

and a more technical overview:
"Each text sample represents text data and consists of a text string, optionally followed by one or more text modifiers, fully consistent with the TextSample format specified in 3GPP TS26.245. The text string represents the text to be displayed during a certain period, while the modifiers carry the changes that are to be applied to the text string during the time that the text is displayed, such as text colour changes"

specifications

you can download a draft of iso 14996-17 here (http://www.itscj.ipsj.or.jp/sc29/open/29view/29n5831t.doc)
it heavily relies on the 3GPP TS 26.245 Timed text format specs, which you can find here (http://www.3gpp.org/ftp/Specs/html-info/26245.htm)

[ac-chan123]

You can find the final commete draft at http://www.itscj.ipsj.or.jp/sc29/open/29view/29n5831c.htm. The .doc file at the bottom contain it.

AC-Chan(Robert Vincenz)

[bond]

great link! thanks a lot :)

[ac-chan123]

There are not so much places to find (legal) stuff about MPEG. I only know this ones:
-http://www.itscj.ipsj.or.jp/sc29/ (MPEG and JPEG)
-http://www.chiariglione.org/mpeg/
-http://garuda.imag.fr/MPEG4/syssite/syspub/index.html (MPEG System HP)
-http://www.tnt.uni-hannover.de/project/mpeg/audio/ (MPEG Audio)
-http://www.m4if.org/ (MPEG 4 Industry Forum)
-http://bs.hhi.de/ (under People you find "the heads" of H.264)
-http://www.iso.org/iso/en/ittf/PubliclyAvailableStandards/

edit:
-http://www.3gpp.org/specs/numbering.htm (3GPP Multimedia Specification)

AC-Chan(Robert Vincenz)

[Kaiousama]

fully consistent with the TextSample format specified in 3GPP TS26.245

Do you know any link to this "3GPP TS26.245" document/format ?
I've done a google search but only returns the same mpeg4-iso definition document from where i've taken the sentence.

[ac-chan123]

I have found in in two minutes. first search at googel for "3GPP TS26.245 pdf". there was no result. Then i go to the official HP of the 3GPP and go the following way Specification -> go here(the secound big blue link) -> 26 Series -> TS 26.245. There we are.
Version 2.0.0 is the newsed downloadable Specification and they work on Version 6.0.0(but there is no Version between them !???!).
The document is a MS Word File !!!

[Kaiousama]

Thanks ac-chan123, i've noticed the word document is marked as version 6 when you open it.
Direct link is here (http://www.3gpp.org/ftp/Specs/html-info/26245.htm)

Is there anyone here interested to develope a subtitling application that supports this standard?

[ac-chan123]

Where can you read Version 6 in this file? i see in the first line "3GPP TS 26.245 V2.0.0 (2004-06)".
I think you mean the Release number 6 from the Title("3rd Generation Partnership Project;
Technical Specification Group Services and System Aspects Transparent end-to-end packet switched streaming service (PSS);
Timed text format(Release 6)").

PS: sorry i have forgotten to post the link.

[unmei]

Kaiousama wrote
Is there anyone here interested to develope a subtitling application that supports this standard?

Interested yes, but.. :D

For one i think this is going to be a important format, so it would be a good idea to support it.
But first i have lots of other things to do, besides and for u96 - it would be a bit stupid to try integrating it now, cluttering the project even more.
Also the spec is a bit confusing to me, it would probably require quite an effort to write a en/decoder and chances were very high i understood some aspects wrong and implemented it wrong (reference files or a reference writing/reading application would help).
At last i'm a bit in doubt we would gain much from an applcation that only supports reading/writing the pure text samples, without the whole mpeg-4 stream thing around it - it is probably more intelligent to have an application that converts to/from a existing text format when it reads/writes the complete mpeg-4 files (ie a muxer like mkvmerge for matroska, just for mpeg-4). On the other hand if Mosu would add a option to read a .3gp text file in mkvmerge, it were very reasonable for me to add .3gp output to u96, but like i said not now :)

[Kaiousama]

Originally posted by unmei
Also the spec is a bit confusing to me, it would probably require quite an effort to write a en/decoder and chances were very high i understood some aspects wrong and implemented it wrong (reference files or a reference writing/reading application would help).

Surely having a couple of sample scripts will help much more than the actual paper only :rolleyes:


At last i'm a bit in doubt we would gain much from an applcation that only supports reading/writing the pure text samples, without the whole mpeg-4 stream thing around it - it is probably more intelligent to have an application that converts to/from a existing text format when it reads/writes the complete mpeg-4 files (ie a muxer like mkvmerge for matroska, just for mpeg-4). On the other hand if Mosu would add a option to read a .3gp text file in mkvmerge, it were very reasonable for me to add .3gp output to u96, but like i said not now :)
Times are still young, since there is no muxer/render for this format, probably when someone will decide to make the first step all will become more easy for the others.
If i've well understood even 3gpp format is xml based so probaly, if you will decide in a future to support it, it would not be a very huge work since even your application is already xml based ;)
My question was more meant to check the people's compliance to the upcoming of another subtitle format.

see you

[bond]

Originally posted by Kaiousama
My question was more meant to check the people's compliance to the upcoming of another subtitle format.i am currently aware of two tools working at providing converting current subtitle formats (srt/ssa) into the mpeg-4 one when muxing to .mp4, nothing released till now tough

i think most of the time only the fact that its a format of mpeg-4 pushes it already


edit: i found some specs about mpeg-4 part 17 subs (heavily relies on 3GPP TS 26.245) here (http://www.itscj.ipsj.or.jp/sc29/open/29view/29n5831t.doc)

[Drachir]

This news looks interesting:

http://developers.videolan.org/vlc/NEWS

" ...
Demux:
* Added initial mp4 and mpeg-ts text track support
...
Codecs:
* 14496-17 MPEG TS text support
* MPEG-4 text support
...
Stream Output:
* Text track muxing for mp4
* 14496-17 text track muxing for MPEG TS


But last time i muxed an avi to mp4 with vlc, the resulting mp4 file has no BIFS/OD :( .

[bond]

yep, they are working on it, but its still not spec compliant, so dont use it!

the bifs/od track is not mandatory afaik

[bond]

just for completeness, its seems that with mp4box there is one of the first tools available that is able to create iso 14496-17 text streams inside .mp4
read more about it in this thread (http://forum.doom9.org/showthread.php?s=&threadid=86050)

[Elias]

This is great news bond, thanks a lot for it! Is the latest build of MP4box that support this final draft available yet?

[bond]

my post was from 2004 ;)
mp4box indeed supports creating these streams already