[broxburn]

I get around the .sup problem by saving as VOB/IDX (they are still a mess), but I replace the colours in the IDX file with the values derived from an IDX file saved by VOBSub Configure.
The values are generic black/white subs

Thus:

# The palette of the generated file
palette: 0300e3, e83f07, 000000, ffffff, 12ea11, eb12eb, faff1a, 0b5c76, 7c7c7c, e0e0e0, 701f05, 077108, 01006c, cd0be9, d2aa10, 730972

# Custom colors (transp idxs and the four colors)
custom colors: OFF, tridx: 1000, colors: 000000, ffffff, 000000, 000000

Is replaced with:

# The original palette of the DVD
palette: 000000, cbcbcb, 000000, 000000, 000000, d6ec38, 000000, 000000, 000000, cbcbcb, 000000, 000000, 000000, cbcbcb, 000000, 000000

# Custom colors (transp idxs and the four colors)
custom colors: OFF, tridx: 1001, colors: 000000, 000000, cbcbcb, 000000