The game's clock runs at a slightly different rate from real time

What to know

A game converts its timer into its own time unit, and the conversion is often rounded. POD multiplies timeGetTime() milliseconds by 65 to get 16.16 seconds, where 65.536 is exact, so its race clock runs at 65/65.536 = 0.99182 of real time, 0.82% slow (observed in FUN_004ae894). Lap times and records are in this slow time.

Measure it: record the game's clock and the wall clock over a long run and divide. POD gave 0.99181 over 490 s, against 0.99182 predicted (measured).

For a port:

• Keep the original's factor and units, and mark any change as a deviation.
• Look for a clamp on the frame time (POD: 700 to 30000, 10.7 ms to 458 ms) and for how a long frame is split into steps (POD: equal steps of at most 3 × a step unit). With a variable step, an exact replay needs the original's sequence of frame times, not only the inputs.
• Other clocks may run on real time. POD's countdown uses timeGetTime directly (5.5 s of wall time), while the race clock and physics use the converted frame time.