PAL games @60Hz with slower sound

john4p · 20 December 2018, 08:29

Hello Toni,

I recently got a cheap Windows tablet (Cherry-Trail) with a display that only runs at 60Hz. WinUAE works very well on it.

Playing Pinball Dreams/Fantasies/Illusions and Slam Tilt with vsync at 60Hz actually is a lot of fun. It kinda feels more realistic than playing at 50Hz.
But of course the sound is too fast.

I know the sound is tied to the framerate. Well, certainly the points at which the sounds are played back are.
But would it be possible to add the option to play every sound file at ~18% slower speed?

That way we could play any Amiga game with faster 60Hz gameplay but with "50Hz sound"...

Is something like that feasible?

Toni Wilen · 20 December 2018, 09:25

Not possible without side-effects. Audio DMA (and every Agnus DMA channel) in Amiga is tied to horizontal sync (=number of lines/frame).

john4p · 20 December 2018, 09:37

Ah okay, that's too bad. Thanks for the quick reply!

edit: Pinball Dreams & Fantasies NTSC-versions are a godsend.

EmilAmiga90 · 01 November 2019, 07:32

I see this topic is one year old, but just out of curiosity, since 18% is about 20%, wouldn't it possible to "simply" shout sound DMA fetch one line every five? (os something like that).

mdrejhon · 01 December 2020, 23:10

Better yet, I have come up with a simple realtime standards-conversion algorithm to play 50Hz PAL at 50fps on 60Hz displays. I have come up with a software-based VRR algorithm, www.testufo.com/vrr -- look at how framerate ramps up and down without stutter.

More relevant demo to emulation:
There's a 50fps smooth demo you can play at:
www.testufo.com/framerates-versus#&framepacingerror=0&framerate=50&compare=1&showfps=1

50fps stuttery versus 50fps VRR-emulation smooth (high speed realtime standards conversion algorithm that even still works in JavaScript). Run that test at 60Hz, and you see 50fps stutter is completely gone.

That way, people can play 50fps games at 60Hz, without the same amount of stutter. It's not perfect, but it can make the experience much more pleasant, at least on 60Hz sample-and-hold displays that doesn't have ability to do 50Hz.

Toni, if you need help with such an algorithm, contact me.

kokoko3k · 02 December 2020, 07:28

Nice, Does it add input latency?

john4p · 20 September 2022, 23:19

^ Got a VRR display now but that software VRR implementation looks perfect. That's crazy.

20 December 2018, 08:29	#1
john4p Competition Moderator Join Date: Feb 2008 Location: Germany Posts: 4,756	PAL games @60Hz with slower sound Hello Toni, I recently got a cheap Windows tablet (Cherry-Trail) with a display that only runs at 60Hz. WinUAE works very well on it. Playing Pinball Dreams/Fantasies/Illusions and Slam Tilt with vsync at 60Hz actually is a lot of fun. It kinda feels more realistic than playing at 50Hz. But of course the sound is too fast. I know the sound is tied to the framerate. Well, certainly the points at which the sounds are played back are. But would it be possible to add the option to play every sound file at ~18% slower speed? That way we could play any Amiga game with faster 60Hz gameplay but with "50Hz sound"... Is something like that feasible?

20 December 2018, 09:37	#3
john4p Competition Moderator Join Date: Feb 2008 Location: Germany Posts: 4,756	Ah okay, that's too bad. Thanks for the quick reply! edit: Pinball Dreams & Fantasies NTSC-versions are a godsend. Last edited by john4p; 27 December 2018 at 13:28.

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20 December 2018, 09:25	#2
Toni Wilen WinUAE developer Join Date: Aug 2001 Location: Hämeenlinna/Finland Age: 49 Posts: 26,504	Not possible without side-effects. Audio DMA (and every Agnus DMA channel) in Amiga is tied to horizontal sync (=number of lines/frame).

01 November 2019, 07:32	#4
EmilAmiga90 Registered User Join Date: Sep 2018 Location: Rome / Italy Posts: 22	I see this topic is one year old, but just out of curiosity, since 18% is about 20%, wouldn't it possible to "simply" shout sound DMA fetch one line every five? (os something like that).

01 December 2020, 23:10	#5
mdrejhon Chief Blur Buster Join Date: Mar 2013 Location: Toronto, Canada Posts: 40	Better yet, I have come up with a simple realtime standards-conversion algorithm to play 50Hz PAL at 50fps on 60Hz displays. I have come up with a software-based VRR algorithm, www.testufo.com/vrr -- look at how framerate ramps up and down without stutter. More relevant demo to emulation: There's a 50fps smooth demo you can play at: www.testufo.com/framerates-versus#&framepacingerror=0&framerate=50&compare=1&showfps=1 50fps stuttery versus 50fps VRR-emulation smooth (high speed realtime standards conversion algorithm that even still works in JavaScript). Run that test at 60Hz, and you see 50fps stutter is completely gone. That way, people can play 50fps games at 60Hz, without the same amount of stutter. It's not perfect, but it can make the experience much more pleasant, at least on 60Hz sample-and-hold displays that doesn't have ability to do 50Hz. Toni, if you need help with such an algorithm, contact me.

02 December 2020, 07:28	#6
kokoko3k Registered User Join Date: Nov 2020 Location: italy Posts: 23	Nice, Does it add input latency?

20 September 2022, 23:19	#7
john4p Competition Moderator Join Date: Feb 2008 Location: Germany Posts: 4,756	^ Got a VRR display now but that software VRR implementation looks perfect. That's crazy.

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