At first glance it looks like the first 4 bytes are a magic/stamp/identifier. There are two little-endian shorts after that, probably width and height. After that is the pixel data I guess, in linear 8bpp.
EDIT: At the end of the pixel data there are an extra 512 bytes, which I would suspect are 2-byte palette values (which makes 256 colours). However if I try using this in Tile Molester as BGR555 it doesn't look very right, so I'm not sure. I mean, I could say that it might be BGR565 or some other variation but that shouldn't matter much, the main issue is that there's just too much black.
EDIT2: Aha, I got it. Instead of those 512 bytes at the end being the palette data, it was actually the first 512 bytes after the dimensions; then comes the pixel data until the end of the file.
AREA1_CHIP.obm
avg_billy.obm
This is what Tile Molester gives with 8bpp linear, 2-dimensional, and a 15bpp BGR (555) palette at an offset of 8 with length of 256 (Intel order). Go to 0x208 since that's where the pixel data starts.
Taking a close look at the palette data, it appears to use all 16 bits so it's probably BGR565 instead of 555. That's probably what's causing the corruption (it can make a big difference). Possibly RGB instead of BGR too, since I'm not sure whether Billy should look that blue.
I can maybe make something for this, although I'm a bit busy at current. I'll make it once I have the time, but if someone else wants to do it first then feel free.
EDIT: At the end of the pixel data there are an extra 512 bytes, which I would suspect are 2-byte palette values (which makes 256 colours). However if I try using this in Tile Molester as BGR555 it doesn't look very right, so I'm not sure. I mean, I could say that it might be BGR565 or some other variation but that shouldn't matter much, the main issue is that there's just too much black.
EDIT2: Aha, I got it. Instead of those 512 bytes at the end being the palette data, it was actually the first 512 bytes after the dimensions; then comes the pixel data until the end of the file.
AREA1_CHIP.obm
avg_billy.obm
This is what Tile Molester gives with 8bpp linear, 2-dimensional, and a 15bpp BGR (555) palette at an offset of 8 with length of 256 (Intel order). Go to 0x208 since that's where the pixel data starts.
Taking a close look at the palette data, it appears to use all 16 bits so it's probably BGR565 instead of 555. That's probably what's causing the corruption (it can make a big difference). Possibly RGB instead of BGR too, since I'm not sure whether Billy should look that blue.
I can maybe make something for this, although I'm a bit busy at current. I'll make it once I have the time, but if someone else wants to do it first then feel free.