Quicktime subtitles revealed
During the Macworld 2008 keynote in January, Steve Jobs introduced iTunes movie rentals that supported multiple audio tracks and subtitles. It has been over two months now and although subtitle support has already been implemented in iTunes, Quicktime and all of the current-generation video-capable iPods, subtitled movies have yet to appear in iTunes Store. Luckily, a few very clever hackers have figured out this undocumented new feature.
The subtitle track is actually a 3gpp timed text track with the subtype atom set to ’sbtl’. It will work with all current-generation video-capable iPods (Classic, Nano, Touch and iPhone) as well as iTunes, Quicktime and even AppleTV (Take 2). Creating subtitled videos might be a bit complicated but it is tremendously easier than trying to create Closed Captions. This tutorial will help you to add any subtitles (as long as they are in SRT format) to your MP4 movies. It is tested with Quicktime 7.4.1, iTunes 7.6.1 and on an iPod Touch with firmware 1.1.4.
Note: I did not discover any of these features. All credits must go to entropic from the Handbrake forum and audiovizual from Doom9. This tutorial is written based on the following materials:
- http://forum.doom9.org/showthread.php?t=136170
- http://forum.handbrake.fr/viewtopic.php?f=14&t=5520&p=31577
- http://forum.handbrake.fr/viewtopic.php?f=4&p=31698
You will need:
- MP4Box (’sudo apt-get install gpac’ for Ubuntu or http://www.videohelp.com/tools/mp4box for Windows)
- Dumpster (http://developer.apple.com/quicktime/quicktimeintro/tools/)
First off, convert your .srt file to a .ttext file.
MP4Box -ttxt path_to_srt_file
You can edit the resulting ttext file to fit your needs. When you are done, add the track to your movie.
MP4Box -add path_to_converted_text_track:lang=language_code path_to_movie_file
Now your movie contains the 3gpp timed text track. Next step is to use Dumpster to set the correct atoms in the movie so that iPods and Quicktime will recognize it as a subtitle track.
Drag your movie file over the dumpster.exe to open it. Navigate to ‘moov -> trak -> mdia -> hdlr’ (make sure you choose the last ‘trak’ in the list). Click on ‘Component subtype’ and replace everything after the last $ sign in the text box in the bottom of the window with ‘7362746c’ (minus the quotes).
The result should look something like this:
Now Quicktime and iTunes will be able to display your newly-created subtitles. To be able to select the track on an iPod, an extra step is necessary.
Open the movie file in Dumpster again. Go to ‘moov -> trak -> tkhd’ and replace the ‘Alternate Group’ atom’s last zero with a 2 (see the screenshot below), apply th changes and close Dumpster.
Congratulations! Your subtitled movie is now ready. All you have to do now is enjoy 
If you have any questions or problems, post them in the comments section, I’ll try to reply as soon as possible.
veebruar 28th, 2009 at 11:03
Thanks for great information.
After I add subtitle by mp4box, it makes mp4 file without any errors.
But, it make component subtype as ‘text’.
So, I open the mp4 file by hex editor and change the ‘text’ section to ’sbtl’.
Now, I’m tring to check ‘alternate group’ part but there is no way to check.
dumpster utility is Mac application.
There is no windows ‘moov’ checking utility.
Could you give me any idea to check this out?
Thanks.
veebruar 28th, 2009 at 08:48
Actually there is a Windows build of Dumpster.
You can get it here: http://hendrik.kaju.pri.ee/failid/dumpsterplussmp4box.zip
märts 2nd, 2009 at 01:16
Thaks for dumpster.
I checked several mp4 & m4v files.
001.m4v: I converted.
002.m4v: Movie trailer from Apple.
I checked ‘Alternate Group’ and its atom’s last are all zero.
Could you explain why do we need to change this ‘Alternate Group’ to ‘2′?
märts 2nd, 2009 at 01:57
I couldn’t get the subtitles to show up on my iPod without Alternate Group set to 2 but YMMV.
märts 2nd, 2009 at 05:14
Do you using iPod 5th (video pod)?
I’m using iPod touch 2nd generation.
The 2nd generation ipod touch plays without the option “Alternate Group” sets.
Thanks for your kind explain.
I’ll googling for more information.
märts 2nd, 2009 at 08:23
Yeah, I am using the 2nd generation Touch. When I wrote this tutorial, the Alternate Group atom was needed but new firmwares may have changed this.
I’ll try update the tutorial to make it simpler and reflect MP4Box’s new features (which means that you don’t have to use Dumpster anymore).
märts 24th, 2009 at 06:16
How would you create more than one language track?
märts 30th, 2009 at 11:32
Check out the new iSubtitle. This is the app of all apps !!!
Makes adding soft subs a breeze.
http://www.bitfield.se/isubtitle/index.html
aprill 7th, 2009 at 11:41
iSubtitle is nice but if you are a Mac OS X user I would advise to use Subler and Metax.
With Metax you add all tags including rating etc wich showup perfectly on your AppleTV.
With Subler you add as many as you like subtitles including language tags, make the movie showup as HD etc.
http://code.google.com/p/subler/
and
http://www.kerstetter.net/page53/page54/page54.html
juuli 20th, 2009 at 06:50
Hi,
I followed all the steps but still I’m unable to see the subtitles:
I’m using itunes 8.2.0.23 and quicktime 7.6
august 4th, 2009 at 10:14
Yes, firmware 3.0 and last itunes, and not working anymore. I used to make movies following this tutorial, no problems so far.
I even updated my ipod touch 2G to 3.0, and then restored from backup, one movie with subs kept working, but any new I make is not longer showing subtitles.
august 19th, 2009 at 10:10
do
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