how does one insert subtitles in a mp4 file?

[androctonvs]

I want to insert portuguese subtitles into the mp4 files i'll be watching in my psp... how can I patch the subtitles in the mp4 file?

Thanks in advance.

[Macche]

also i have interest to insert sub in mp4 video....

it's possible to implement this feature in a future version of pspvideo9??

thx

[androctonvs]

here you go.
http://www.videohelp.com/forum/viewtopic.php?t=272736

do this and then just convert to mp4.