I’ve been using this and its sibling (AVItools) since they were first released, and I used MKVtools (my favorite) before that for over a year, and I love ‘em all (though splitting MKVtools into 3 different apps seems a bit pointless and/or greedy to me). However, v. 3.1.2 has a serious problem that kills its usefulness: When I used it on 2 different mp4 files to remove a Japanese audio stream and a couple of subtitles from each movie and remux them into new mp4s that kept only the English audio stream, the audio disappeared. In case you’re wondering, 1) I know these apps inside and out, so it wasn’t operator error; 2) the problem occurred with 2 different movie files and on 2 different Macs, so it wasn’t a one-off bug; and 3) when I re-did both movies with MKVtools, they came out fine, further proving #1 and #2 above.

Once it’s fixed, MP4tools will again be a decent app. There are freeware apps (MKVtoolnix, remux, Subler, etc.) that together can nearly do everything MP4tools does. However, the convenience of having all those capabilities together in MKVtools was worth $20 to me. But now that this developer has split up all those capacities into 3 different apps, I’d rather just stick with all the other freeware.