Use vgm_ptch from the
vgmtools.
Usage:
If it's an old VGM file (pre v1.51 for SetLoopMod or 1.60 for SetLoopBase) you will have to update it with the following command
Code:
vgm_ptch -UpdateVer:1.51 myfile.vgm
then you can
Code:
vgm_ptch -SetLoopMod:0x20 myfile.vgm
This multiplies the loop count (notice hexadecimal notation, the actual loop modifier is a 4.4 fixed point value, or the value divided by 16).
OR
Code:
vgm_ptch -SetLoopBase:-100 myfile.vgm
This subtracts a "base value" from the default loop count, so if set to -100 (Notice the negative value), and the default loop count is 2, it will loop 102 times.
SetLoopBase will add or subtract from the player's loop count preference, while SetLoopMod will multiply or divide this value.