I want to add subtitles (srt files) to my movies ....

It is possible to use .SRT files with movies in QuickTime Player by installing Perian. However this does not work on the AppleTV 2.

I suggest you look at these two program. The first is Submerge, this 'burns in' the subtitles so they are part of the video, with this approach the subtitles are always on and cannot be turned off since they are now part of the video itself. The second program is iSubtitle, this adds the subtitles as a proper QuickTime subtitle track which can be turned on or off, you can even include multiple languages. As the subtitles are converted to a proper QuickTime subtitle track they will work on an AppleTV 2 unlike a separate .SRT file.

Both programs are actually produced by the same company. See http://www.bitfield.se/index.html

Try Subtitle Writer on Mac App Store. It's for Quicktime Player X and iOS devices. I don't know Apple TV works or not.

Try Subtitle Writer on Mac App Store. It's for Quicktime Player X and iOS devices. I don't know Apple TV works or not.

From forum snconnect, I found a solution which works like a charm:

You may prefer to this step by step guide on how to add subtitles to mkv, mp4, AVI such as add SRT, ***, SSA, SUB, IDX to MKV/MP4/AVI.

Hope it will help you more or less.

I also have the need to add subtitles to video files.
One of my friends show me a step by step guide on how to add subtitles to MKV, MP4 at How to Add .srt, .ssa,.sub, .idx Subtitles to MKV Files
After tried, it really helps.
Now i like to share it here, hope it also helps for you.
This guide can help:
Add all kinds of subtitles to MKV such as add SRT to MKV, add *** to MKV, add SSA to MKV, add SUB to MKV, as well as keep or change MKV to other video formats like MP4, MOV, AVI, WMV, FLV, MPEG, ASF, DV, RM, WebM, OGV, etc
Embed subtitles to almost all kinds of video formats like MP4, AVI, WMV, MOV, FLV, ASF, WebM, OGV, TS, MTS, M2TS, MOD, MPEG, H.263, H.264, Apple ProRes, F4V, SWF, MXF, MVI, M4V, QT, DAT, 720p/1080p AVCHD and more;
Work on both Mac OS X or Windows computer

It is easy to add hard code subtitle into videos on Mac. Here is a guide on how to add subtitle to movie. With this tool, you can not only add subtitle file, like SRT, ***, SSA, IDX, into movies, but also adjust the subtitle font, color, style at will. Besides converting between various video and audio formats, you can trim, crop, merge, add or remove audio tracks easily.

I recommend to take a look at "Subler" (https://bitbucket.org/galad87/subler/overview).