How do i add softsubs to .mp4 file?

[LCaveman]

Hello guys, i am trying to add softsubs ( option to enable/disable subtitles) to a Format: H.264/MPEG-4 AVC file without loosing quality,i've done some google search but i just can't find a straight easy way to do this, some people say it can't be done at all,remember i don't want to hardcode subtitles, that i know how to do.Do you guys know of any program like AVIAddXSub is for .avi files that works with .mp4 files?, or any easy step by step way of doing this, any help will be appreciated,thank you.

P.S. Also , i'd like to keep original file format, so please don't suggest to convert file to other format,you loose quality that way.Don't you?

[xje4bv]

You could try the posts as mentioned in;
http://forum.handbrake.fr/viewtopic.php?f=14&t=5853&start=50
and
http://forum.handbrake.fr/viewtopic.php?f=14&t=5520

I didn't try them out as I'm in a bit of a hurry now. Hopefully it should work.