Hello forum ^^

Okay so I used MkvtoMp4 to add a subtitle track(.ASS) to an mp4 file, but the resulted subtitles had a different style, which is not important, what is important is the alignment....I used Subtitle Edit 3.3.10 to change the alignment of some texts to Top/center but they appeared bottom/center.

Is it possible to fix this? It is important :P

Whats the difference between mp4 and m4v? Is one of them more compatible with other devices?

thanks ^^