Quantifying slow down of the game Gravitar on Arcade1up's "Atari Legacy Arcade Machine Centipede Edition" cabinet

arcade1up_gravitar_slowdown.org

Quantifying slow down of the game Gravitar on Arcade1up’s “Atari Legacy Arcade Machine Centipede Edition” cabinet

What is this about?

Gravitar on Arcade1up’s Centipede cabinet feels extremely slow compared to the original 1982 cabinet and MAME running on my 2019 MacBook Pro. I wanted to quantify exactly how much slower it is in order to log a support ticket with Arcade1up.

Methodology

The red planet in the first universe has a countdown timer called escape time:

I figured I could calculate exactly how long each tick of the countdown timer takes to decrement, both on the Arcade1up and on a real machine, and compare the results to determine the slow down as a percentage increase.

For source material I took a video of myself playing the red planet on the Arcade1up in mp4 format, and found a YouTube video showing the same planet being played on an original machine. I downloaded the YouTube video as an mp4 using https://10downloader.com.

Next I found a video player, mpv, that shows millisecond timestamps during playback and has keyboard shortcuts to advance frame by frame, allowing me to find the precise timestamp when each tick of the escape time countdown timer decrements.

Notes on using mpv

• Run mpv from the command line providing the video as an argument
• When the video opens click on the timestamp in the bottom menu to make it show milliseconds
• Next and previous frames can be navigated using “,” and “.” keys respectively
• Hold down the keys to play at the normal frame rate

Arcade1up timestamps

• Source: My own video of gameplay
• File: arcade1up_gravitar.mp4

Escape Time	Video Timestamp (s.ms)	Elapsed
17	0.233	0
16	2.554	2.321
15	4.884	2.33
14	7.213	2.329
13	9.542	2.329
	Mean	2.32725

2.33 seconds per tick.

Original arcade timestamps

• Source: Atari Gravitar Arcade Cabinet Gameplay video - Color Vector downloaded using https://10downloader.com
• File: original_cabinet_gravitar.mp4

Escape Time	Video Timestamp (s.ms)	Elapsed
22	24.798	0
21	26.663	1.865
20	28.435	1.772
19	30.270	1.835
18	32.105	1.835
17	33.907	1.802
	Mean	1.8218

1.82 seconds per tick.

Calculate percentage increase

$ echo '(2.33-1.82)/1.82*100' | bc -l
28.021978021978022
$

Conclusion

The Arcade1up is 28% slower than the original arcade.

As someone who bought the machine primarily to play Gravitar, such a heavy slow down makes the game unenjoyable to play and defeats the purpose of buying the machine.

escape_timer.jpg

red_planet.jpg