How can I convert "timed text" (ttxt) 3GPP video (m4a/mp4) to another format?

[hatsoff]

Hi, all.

I've got an *.m4a file that appears to have been created on a mac, and which according to mediainfo is encoded in the 3GPP "timed text" format, which I think is some kind of quicktime codec.

The target format is ultimately xvid, but if I can get it to any other common format I can always re-encode. It's just a powerpoint-style presentation, so quality isn't really a big issue so long as I can read the text.

So far, I've tried mencoder, avidemux and ffmpeg in ubuntu, and virtualdub and tmpgenc in win xp, but none of those worked for me.

The source file is very small (9.2MB), so I uploaded it to yousendit, in order that some friendly fellow might download it and investigate the matter more directly: Here's the link (http://www.yousendit.com/transfer.php?action=download&ufid=BA12DF222DC0E5AE).

Any suggestions would be much appreciated. Thanks!

[Jalavera]

ttxt is not a video codec is a subtitle format contained in MP4 file format.
You can extract it by using YAMB/mp4box.

[smok3]

i'am just investigating the opposite, that is how to create tt subs, this is what i figured out for now:
a. there seems to be a plugin for subtitle workshop that would supposedly allow the export to that format (maybe import as well?) - check http://www.jeroenwijering.com/?item=Making_Video_Accessible
b. there seems to be java tool that will supposedly do the job - http://ncam.wgbh.org/news/pr_20030313.html

[Jalavera]

i'am just investigating the opposite, that is how to create tt subs, this is what i figured out for now:
a. there seems to be a plugin for subtitle workshop that would supposedly allow the export to that format (maybe import as well?) - check http://www.jeroenwijering.com/?item=Making_Video_Accessible
b. there seems to be java tool that will supposedly do the job - http://ncam.wgbh.org/news/pr_20030313.html

YAMB/mp4box can convert srt subtitle to GPAC ttxt format and vice versa

[smok3]

Jalavera: that is excelent info, tnx.

edit: any clues what charset is mp4box expecting as input (no it is not utf-8) or how to tell it what charset file is in?
edit2: nm, not the correct format anyway.

[hatsoff]

I installed Yamb as directed, and I can extract the ttxt data. However, I want to convert it to a workable video format (like xvid or mpeg-2), not just extract a ttxt file. Yamb also allows conversion to SRT (SubRip) format, but again, this is nothing that I can work with. I need something that mencoder or avidemux can handle.

Thanks for the help so far, guys! Here's hoping we can eventually close this case.

[nm]

Yamb also allows conversion to SRT (SubRip) format, but again, this is nothing that I can work with. I need something that mencoder or avidemux can handle.
MEncoder and Avidemux do handle SRT.

[Reimar]

MEncoder and Avidemux do handle SRT.

In addition MPlayer and for all I know also mencoder can handle mov ttxt itself as well (except for any fancy formatting)...

[nm]

So far, I've tried mencoder, avidemux and ffmpeg in ubuntu, and virtualdub and tmpgenc in win xp, but none of those worked for me.
I tried Avidemux to convert the png "video" frames to MPEG-4 ASP (XviD, lavc), and it almost works if you use the "Resample fps" filter. However, frames get delayed too much (or at least the second one does: it only appears after a minute or so).

You'll also need to use MP4 or MKV as output container format if you want to keep the AAC audio (to copy it instead of re-encoding).