All of a sudden movies in quicktime have no sound. I want to burn the movie to DVD so I want to make sure it works in qt.

After browsing the boards I came across a post that said someone had too many codecs and needed to delete some. These are the codecs in my quicktime library. I don't want to delete anything without asking first, so if you could please help me out with what I can delete and what to keep I'd appreciate it.

Also if you think there is a codec missing or another reason that the sound is not working, please let me know.

MacHD>Library>Quicktime>

A52Codec
AC3Codec
AC3Codec(another one)
AC3MovieImport
AvilImporterIntel(im guessing i can delete this one since im on ppc)
DivXDecoder
DivXEncoder
Flip4MacWMVAdvanced
Flip4MacWMVExport
Flip4MacWMVImport
FLV
Perian
XviD_Codec alpha
XviD_Codec-r58(another intel)
XviDDelegate