07424: cbuster and clones: Lack of slowdown

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
07424	Timing	Minor	Always	Sep 15, 2019, 20:38	Sep 21, 2019, 21:01

Tester	ICEknight	View Status	Public	Platform	MAME (Official Binary)
Assigned To		Resolution	Reopened	OS	Windows 10 (64-bit)
Status [?]	Acknowledged			Driver	dataeast/cbuster.cpp
Version	0.213	Fixed in Version		Build	64-bit
		Fixed in Git Commit		Github Pull Request #

Summary	07424: cbuster and clones: Lack of slowdown
Description	The original hardware seems to struggle in a few points across the game where too many enemies are on screen. This footage shows some noticeable slowdown going on until most of the enemies are cleared from the screen:
Steps To Reproduce	Reach the end of level 2 (or load the provided savestate for the cbuster set). After the boss appears, so will a swarm of enemies which would slow down the action on real hardware. No slowdown is present in MAME.
Additional Information
Github Commit

Flags	Verified with Original
Regression Version
Affected Sets / Systems	cbuster and clones

Attached Files	cbuster.zip (11,030 bytes) Sep 15, 2019, 20:38 Uploaded by ICEknight
	cbuster boss 2 enemy limit test.zip (11,513 bytes) Sep 19, 2019, 22:37 Uploaded by ICEknight
	cbuster before the dogs.zip (11,341 bytes) Sep 19, 2019, 22:38 Uploaded by ICEknight

No.16911 ICEknight Tester Sep 15, 2019, 22:39	I'm in contact with the owners of this board, so feel free to ask if you need any details.
No.16915 Tafoid Administrator Sep 16, 2019, 17:51	If be curious if the same thing happens in 0.212. There was some adjustment to the way things work to limit the "audio speedup" in certain situations which has been reported for many Data East games.
No.16916 MetalGod Senior Tester Sep 17, 2019, 09:29 edited on: Sep 17, 2019, 11:25	If you refer to the change in 00389, that modification is set to be applied in mame 0.214. So, mame 0.213 is a valid version to check the issue
No.16920 MetalGod Senior Tester Sep 17, 2019, 23:45 edited on: Sep 18, 2019, 00:35	In that pcb video you're playing a 2 PLAYER game. Do the same thing in MAME and you'll also have slowdown. In the provided savestate you're playing a 1 PLAYER game. Insert coins and let player 2 enter. Go forward untill the boss and the enemies get into the screen and you'll have the same slowdown as in the original hardware. As in MAME, when playing with only 1 PLAYER during that boss there's no slowdown. 26:00
No.16924 Tafoid Administrator Sep 19, 2019, 01:39	I'm setting this as a BTANB given since MetalGod has affirmed it is based on number of players being played (2 players at same time causes slowdown). If there is more to be said, simply reply here and it will be reexamined.
No.16934 ICEknight Tester Sep 19, 2019, 22:46	The thing that prompted me to record some footage was that I noticed the slowdown a few times while doing a playthrough on my own, so it must be noticeable in 1-player mode as well. I've uploaded a savestate right at the second boss and with 9 enemies on screen, which do cause slowdown. There, you can pick up and throw away (Button 3) any number of them to see how many can be on screen at once without things slowing down. This led to these results: ·1 player + 8 loaded enemies + 1 boss -> Slowdown ·1 player + 7 loaded enemies + 1 boss -> No slowdown ·2 players + 7 loaded enemies + 1 boss -> Slowdown ·2 players + 6 loaded enemies + 1 boss -> No slowdown I'll see if I can manage to get some more footage where those enemies can be counted more easily, next time I come across that cabinet (next year?). I've also uploaded another savestate where the new video always shows some slowdown (at 15:40, 24:08, 43:58-44:00) from the moment the four enemies are loaded until one of them has been defeated, and where it _seems_ to be more difficult to trigger in MAME (but the timing of the falling debris might have to do with it as well).
No.16936 MetalGod Senior Tester Sep 19, 2019, 23:16	In the previos pcb video I showed, in minute 46:36 there's a slowdown. It is another fight against the second boss 1 player + 6 loaded enemies + 1 boss -> Slowdown.
No.16947 Planestate Tester Sep 21, 2019, 19:36	MAME (0.213) doesn't have any slowdown with one player + 7 enemies on screen + 1 boss, but PCB does with one player + 6 enemies on screen + 1 boss.
No.16948 MetalGod Senior Tester Sep 21, 2019, 21:00 edited on: Sep 21, 2019, 21:10	Yeah, thanks to the pcb video I provided it seems iceknight was right. Anyway, the slowdown I mention in 46:36 is very subtle. I think more videos of the pcb would be needed if any developer wanna adjust this more accurately to the real pcb. 46:36 I'll set this to acknowledged If any admin of developer considerer my decision wrong, please correct it.