From How to increase Video Sound Levels on AVI. Files or Mpeg:
If the files are only for watching
once or twice i use ONLY virtualdub,
very easy.
- Open file in virtualdub
- Click on Video -> Direct Stream Copy
- Click Audio -> Full Processing Mode
- Click Audio -> Volume, then check "Adjust Volume of Audio Channels" and
set the slider to for example 303%.
- Click File -> Save as AVI, enter a new filename and Ok.
Thats all, and you dont even have to
know theres something called demux and
mux. But! the file will be big as the
audio is now uncompressed, not very
suitable for archiving.
Edit: If its an Mpeg you need to leave
Video in Full Processing Mode (unless
you got a lot of harddisk space or a
short video) and set a compression (i
would recommend XVid) under the menu
Video -> Compression. This will take
quite a bit longer time btw.