[FFmpeg-user] How do I add subtitles to mp4 files?

[Alexander Kulyakhtin]

Do you know if it is possible to add subtitles to mp4 file using FFMPEG?

Currently I'm trying

ffmpeg -i input.mp4 -i input.srt output.mp4

But I can't see any subtitles in output .mp4

Whereas if I specify output .mkv then I do see subtitiles. However, I need
mp4 not mkv.

Thanks in advance