Bsnes audio bug in some games

Libretro Cores
#1

Hello!!

I can hear a crackling or distorsion in the sound of some games in bsnes and bsnes mercury cores. For example, I can hear an initial distortion in the " Konami sound" when the logo of Konami in Prince of Persia appears and when the title screen music begins, only when appear the first time (that disappear in the next demo sequence). That happens in Axelay (not in the Konami logo but in the beginin of the intro sequence) and other some games too. I can confrim this in Windows, Mac OSX builds and the Higan stand alone emulator. In my real SNES this distortion doesn’t exist.

Thanks for the help

#2

If it happens in Higan standalone, as well, then it’s nothing we’re doing, but you’re going to have a very difficult time proving any problem with the emulator itself. It’s much more likely that there’s an issue on your end. Crackling is almost always a result of dips in the framerate below 60 fps. What kind of CPU do you have? Do you have hard gpu sync enabled? any shaders?

#3

In Windows, it happens with Vulkan and OpenGL (with Hard GPU Sync on and off) with or without shaders enable. The same issue happens in macOS build of RetroArch. My Windows machine have a Core i7 3770k at 4.2 GHz with a dedicated graphics card (Asus GTX 970) and the Mac machine is a Core i5 DualCore 3rd Gen at 2.5 GHz. with Intel Graphics 4000.

Thanks!!!

#4

Something that can happen with beefy CPUs like that is they finish the emulation process in a fraction of a frame and then idle the rest of the frame, and the OS thinks that it should clock down to save power. When it does this, the lower speed can’t maintain 60 fps and you get crackles. Try going into your power settings and set it to “max performance” or whatever and do the same thing with your GPU, just to be safe.

#5

Ok. I found the problem:

https://board.byuu.org/viewtopic.php?f=4&t=1734&start=50#p45349

It’s a memory register emulation that not corrected pass through to the sound DSP module. Yep, this is not a RetroArch fault. By the way, byuu, the author of bsnes/higan, is looking for the Blargg’s test sound roms (especially, spc_dsp6.sfc rom) for fix this bug and improved the DSP emulation. If someone in this forum have it or know about that library of roms, please, give me the information or post in the forum of the link above.

Thanks for the help!!