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Sunday, March 2, 2014

Subtitles - Convert SUP to SRT

Ah subtitles... When ripping Blu Rays from an MKV to M4V (MP4) they used to be quite a pain in the backside (see this previous post for details!). But if you are happy with 'burning in' subtitles (i.e. having them form part of the picture) then Handbrake v 0.9.9 will happily provide this service for you out of the box.

As you can seem you just simply go to the 'Subtitles' tab and choose the subs you want and lo and behold the Bitmap image of the subtitles will adorn your movie:

It even retains the font and colouring because these are images - not text.

Now this is fine for 'Forced Subtitles' (where the characters speak gibberish - in the case above taken from "Thor - The Dark World" - 'Dark Elven') but when you want to have the ability to turn the subtitles on and off, this won't work. These subs are burnt onto the picture. If you want to have the ability to switch languages, or something like that, the subtitles need to be stored in a file - usually a text file.

A media player like VLC does understand the subtitle files that are images natively and will happily let you turn them on and off through a menu option. iTunes or QuickTime does not support image subtitle files - only text. So how to convert the bitmap image to a text file? Well, as ever, it's a bit complex....

Fear not - I shall attempt to steer you through the pitfalls. You will need the following software:

You will need a nice MKV version of your movie with the subtitle track that you want included (no idea what I mean by that, then please refer to a previous blog post of mine on how to do this).

This walkthrough is for a Mac, with a bit of Windows PC software thrown in. I'm sure equivalent software are available for both platforms. The reason I use Subtitle Edit is a friend recommended it and I haven't found a Mac equivalent.

Let's begin...


(1) Open MKVTools and open your MKV file.

(2) Navigate to the "Edit" Tab and choose the subtitle track you want to export (If you aren't sure, open the MKV is something like VLC Player and fiddle with turning on the different subtitle tracks until you find the one you want, then go back into MKVTools).

(3) Check the "Extract Selected Tracks" box on the right and click "OK". Another window will open and you will see the progress of the file extraction. It will store the subsequent SUP file in the same folder as your MKV file.

UPDATE - 14th December 2014 - An alternative to MKVTools

I haven't been using MKVTools recently. I've found a better way using MKVToolNix. I've detailed how to use this in a seperate blog post (which deals with subtitles from DVDs, but can also be used to get the SUP file from Blu Rays using exactly the same method):

Subtitles - Converting a DVD MKV to IDX SUB files on a Mac

Subtitle Edit

Switching to my Windows PC now, I take my extracted file and load up Subtitle Edit

(1) Open the software and select the "Open" menu option then choose your SUP file. It will open into the "Import/OCR" screen like the image below:

(2) The software will now attempt to OCR the subtitle images. In plain english, it will scan the subtitle images and translate what it reads into plain text. No OCR is perfect, it will make mistakes (especially in a fantasy tale like Thor! - "Send in the Kursed" sugggested as being changed to "Send in the Nursed"!) but we can correct those as we go along, ignore them or sort them out later...

(3) And so you end up with an editable list where you can go and make corrections where necessary. Click into the Text box and correct away. If you want to compare it to the source images, then open up the SUP file in a tool like BDSup2Sub and browse through the file.

Now I've only scratched the surface with this program. You can look at the Subs over the video, correct timings and do all sorts of funky things. But if you've ripped the subtitles from the same MKV as you ripped the movie, then there's no need. You simple need to focus on getting the spellings and words correct.

Obviously, in my example, there aren't many lines of text. I appreciate in a fully subtitled movie there is a lot of work potentially - but that's just the way it is!

One you have finished your corrections, save your file as a SubRip (.srt) format and back to the Mac you go...


If you have read some of my other blog posts, you will know I like Subler and it makes this last step super easy. 

(1) Open up the movie (the MP4 or M4V you ripped from the MKV) and click on the + button in the top left-hand corner:

(2) Locate the SRT file you saved earlier and click "Open". You will see the screen below which you just click "Add" on:

(3) Save your work. This also assigns the subtitle a Track ID, which you will need

(4) Now click on the Subtitle track and set the following options:

Language: English (or whatever language you are using)
Alternate Group: None
Forced: All Samples Are Forced
Forced Track: Choose your subtitle track

(5) Now Save again - and you are done!


Here's a screen shot using QuickTime player:

The text subtitles are at the bottom. QuickTime doesn't support the forcing of the subtitles. iTunes does, and so your subs should display automatically - but if they don't just choose them in the menu option manually.


If it's alien speak you're after, or you will always want the subtitles on (such as in a foreign language film) then just burn them straight onto the image using Handbrake. Easy peasy and it retains the nice fonts and colours.

If you use Quick Time or iTunes, and want to turn the Subs on and off, then it's a bit of a painful process, but it works just fine.

As ever - any feedback - please leave me a comment below...

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