How to burn-in two subtitles at the same time?

[Shaorin]

How do I burn-in 2 subtitles at the same time? I don't want to encode twice

[videoAI]

To burn-in two subtitles at the same time without encoding twice, you can use FFmpeg with the `subtitles` filter. Here's a command that does this:

ffmpeg -i input.mp4 -vf "subtitles=sub1.srt:force_style='Fontsize=24,PrimaryColour=&H00FFFFFF&,OutlineColour=&H00000000&,Outline=2,Shadow=0,BackColour=&H00000000&,BackOpacity=100'[sub1];[0][sub1]overlay[tmp];[tmp]subtitles=sub2.srt:force_style='Fontsize=24,PrimaryColour=&H00FFFFFF&,OutlineColour=&H00000000&,Outline=2,Shadow=0,BackColour=&H00000000&,BackOpacity=100'[sub2];[tmp][sub2]overlay" -c:a copy output.mp4

This command assumes:
- `input.mp4` is your video file.
- `sub1.srt` and `sub2.srt` are your subtitle files.
- The subtitles will be burned-in with a white font, black outline, and a black background.

Adjust the `force_style` parameters as needed to fit your requirements.

[Subtitles]

Use MKVToolNix
It will do the job fast without encoding
Just upload the video (add sources) then the subtitle files (Make sure you give each one the correct language code which will help you during play to distinguish between the languages.

If you really want to burn-in (hardcoded) then the previous reply is a better solution.
I personally use only soft coded (selectable subtitles), but that's just me.