What you can do:
(1) Go to / get HandBrake
(2) Choose your video file
(3) Select m4v for file output (in preferences: 'Output Files' - 'Default MP4 extension:' - choose 'm4v')
(4) In 'Subtitles': Choose 'Add external SRT' - check 'Default', else leave unchecked
 [optional] 'Video' - Choose 'Constant Quality' RF 0.00 to bypass another video compression of your assumedly already compressed video and thus preventing quality loss of the video layer. May increase file size though (not tested yet).
In Quicktime you will than be able to turn on / off your previously added Subtitles.
Tested with Mountain Lion - latest Quicktime - VLC - HandBrake (needs VLC installed) - NO Perian - NO divX
since you are seeing "View>Subtitles>English" in Quicktime I would say you have followed my steps as advised; which points to the Subtitles that are possibly faulty.
However I posted a question about quality loss to the HandBrake community and re-thought my steps above. HandBrake was never designed for subtitles muxing. Reencoding will be a quality loss or leads to uncomfortable file sizes (RF 0.00) and it's so time consuming.
If you like follow in my next post what i have finally come to in terms of repacking / converting for Quicktime!
Step-by-step Guideline how to convert / repack MKV and AVI Video Containers into MP4 / MV4 and then adding Soft Subtitles - all playable with (also Moutain Lion) Quicktime / iTunes:
1a) Install latest Subler (adding Subtitles from e.g. subscene.com) here
1b) Install latest MetaZ (iTunes friendly, cool looking Meta-Tags) here
1c) Install latest Perian (for MKV repacking support in Subler) here
1d) Install latest Miro Video Converter (for dealing with .AVI only) here
- All applications are 100% free and legal and run smoothly on Mountain Lion with the one exception of Perian where you have to replace a AC3 codec if you like to play AC3 Audio in Quicktime follow here -
2) Repacking .MKV for Quicktime with SUBLER:
If the Video Layer in your MKV file is already Quicktime friendly (mp4, x264) you can and should avoid reencoding of the Video Layer, otherwise you loose video quality.
Then there is the Audio Layer. If it is Quicktime / iTunes friendly too (AAC), you won't even need to install Perian. Simply use Subler to repack both Video and Audio Layer into the new MP4 / M4V container.
If the Audio Layer is Quicktime / iTunes unfriendly (AC3, DTS, etc.) you will have to convert the Audio Layer. If Perian is installed Subler is able to do exactly that. Subler leaves the Video Layer untouched and only converts the Audio Layer! This is a great, fast method, saving video quality.
In either case you can add external Subtitles to your MP4 / M4V container which will be read by Quicktime and can be turned On or OFF (soft subtitles)!
3) Converting .AVI files to MP4 / MV4 for Quicktime with Miro Video Converter: Simply do this with Miro Video Converter. It's a straight forward, easy-to-use and reliable application. After this step you can also add soft subtitles with Subler.
4) If you like to view your Movies with iTunes instead of Quicktime: MetaZ is a great application to add iTunes friendly Metadata. It searches by title through a web movie database and adds actors, directors, plot summary, art work, etc. When done you can import your Movie into iTunes and it will look really cool and thanks to the Meta data it can be sorted ways better.
- tested on Moutain Lion with Quicktime 10 -
Well, if you can't get it to work with VLC, you could try AVS Media Player, which has support for .sub and .idx. Although as the other poster said, I belive VLC does support them, it may just need it in a different location or something like that.