How to permanently add subtitles to MP4?

[videonewbie22]

Dear Experts,

I have two files:

somevideo.mp4
somevideo.ass

I can play these together with VLC player and see the subtitles.

But I would like to create a new .mp4 file with
the subtitles permanently merged/hard coded into it.

What is the secret to do this?

The simpler the tool, the better.

Thanks a lot!

[aedipuss]

for and easy way convert it to mkv. use mkvmergegui and add the 2 files and then mux into a new mkv. that would still be softsubbed. to hardsub you need to re-encode it and burn the subs in.

[sparkyar]

I use "video to video" and it hardcodes srt subs, dont know about other sub formats

https://www.videohelp.com/tools/Video-to-Video-Converter

[Budman1]

Easiest way is to use Format Factory but do NOT use it's subtitle function. You will need to have AVISynth installed
with the VSfilter.dll and DirectShow.dll filters in its plugins folder. Then create a text file with these 2 lines in it:

DirectShowSource("Path to video\somevideo.mp4")
Textsub("Path to subtitle\somevideo.ass")

Save it as an AVS file (somevideo.AVS) Drag this file to Format factory and it will load as if it were the original video.
It should say somevideo.avs as the source. Just right click this line and select options and a window should open and preview begin to play. Set what ever options you wish EXCEPT do not use subtitles within Format Factory or you will have double and erratic. Then convert to mp4 video.

[Hoser Rob]

I'd go for just just repackaging it as mkv as aedipuss says.

Hardsubs = reencoding = it'll take much longer and you will lose video quality.