The videos were playing just fine only moments ago, when I played through episode 1, but now they're suddenly showing only a black screen, and the video before the final map of episode 4 is playing at the beginning of the episode instead. Sometimes it even blacks out the gameplay screen until I toggle windowed mode. What the hell happened?

Sorry if this issue was posted and solved before, and I simply missed it in the history.

EDIT: It appears Cryptic Passage also starts with a black screen unless I toggle windowed mode. Not sure if this is related or a common thing for everyone.

Perhaps this can help you out.

No, it doesn't...I tried this while trying to solve the music issues. Switching .gog to .ins and back doesn't affect it.

It seems that this is what happens, and each time it's a 50-50 chance of happening (or maybe 60-40 chance), and alt-enter to toggle windowed mode fixes it:
- Game boots up (or i beat an episode), and the screen is black during the title menu, but i can hear the demo and menu sounds.
- FMV cutscenes show only black screens, but I can hear them playing.

The fact that E4's final map's cutscene plays at the start of the episode rather than before the final map is also annoying and it might not be related to the abovementioned problem.

Damn, I would change the topic title to "Keep Getting Black Screens During FMV and Game Boot" or something, but seems I can't...

It seems odd that it just started happening. Did you update your video drivers by chance? With it being a 50-50 chance of working or not, it sounds like there might be something with the way DOSBox passes the video to your display.

Things I'd check:
Play with the output: setting in your dosboxBlood.conf file (make a backup first or copy the line and comment it out with a #)
Possible values are: surface, overlay, opengl, ddraw, and direct3d.

If that doesn't fix the issue, I'd try running it with one of the newer DOSBox builds. I have had quite a bit of luck with the YKHWong SVN builds over the years.