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Author Topic: Help with Altering Skitchin' Soundtrack for Genesis  (Read 1094 times)

twinparadox

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Help with Altering Skitchin' Soundtrack for Genesis
« on: December 07, 2018, 09:44:33 pm »
Ok, this is going to be an odd question, but bear with me. I am drummer who creates medleys of retro game music and complements it with live acoustic drums. I accomplish this by exporting the game music from an emulator and disabling the sound channel(s) that contain the original drums/percussion so that they don't clash with what I'm playing.

Anyway, I have been dying to make a Skitchin' medley but when I tried to disable the sample channel to silence the drums, it ended up silencing the guitar too. I had just assumed the guitar was an FM instrument but it is actually a sample as well! From what I can gather, whoever programmed the music for the game created a sophisticated way in software to add the data points that made of up the waveforms of whatever two samples were going to be played and then streamed that information to the sample channel. There were very few genesis games that attempted this (only 3 that I am aware of after researching) because of how complex of a task it was and how processor hungry it was.

So, now for my question FINALLY lol. Would there be an easy way to hack the game to remove the snare and kick drum samples so that only the guitar samples are played? Or if that would create some kind of an error, I could replace the kick and snare samples with "dummy" samples that were just silence or something.

Although I have never hacked a game before, I am a pretty technical guy and have taught myself a fair amount of programming but I don't really know where to even begin with this. Please let me know if any of you out there have any ideas or suggestions. Thanks!

Supper

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Re: Help with Altering Skitchin' Soundtrack for Genesis
« Reply #1 on: December 08, 2018, 02:38:34 am »
Yeah, Skitchin' uses software mixing for its samples, which the programmer considered one of his greatest technical achievements. (I wouldn't exactly say that Mega Drive music was "plain and boring up until Skitchin'", but whatever).

Most of the samples are uncompressed and simple to change, so I made a quick hack that blanks out the drum samples, which is a lot more straightforward than disassembling the sound driver to do it properly. Use this IPS patch: http://stargood.org/files/skitchin_drum_mute.ips (also the game had some copy protection and wouldn't run with the changes at first, so I had to turn that off too)

The hat and tom aren't samples, so you'll still need to mute whichever channel those are on.

KingMike

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Re: Help with Altering Skitchin' Soundtrack for Genesis
« Reply #2 on: December 08, 2018, 02:46:24 am »
(also the game had some copy protection and wouldn't run with the changes at first, so I had to turn that off too)
The usual EA Genesis checksum protection (aka hard-patching Game Genie "Master Code")?
"My watch says 30 chickens" Google, 2018

Sanedan56

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Re: Help with Altering Skitchin' Soundtrack for Genesis
« Reply #3 on: December 08, 2018, 11:33:33 am »
According to this site the game uses the Electronic Arts sound engine.
I've tried myself to disassemble it, but other projects preoccupied me.
As for the checksum, here is how to get past it.

twinparadox

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Re: Help with Altering Skitchin\' Soundtrack for Genesis
« Reply #4 on: December 08, 2018, 10:22:21 pm »
Yeah, Skitchin' uses software mixing for its samples, which the programmer considered one of his greatest technical achievements. (I wouldn't exactly say that Mega Drive music was "plain and boring up until Skitchin'", but whatever).

Most of the samples are uncompressed and simple to change, so I made a quick hack that blanks out the drum samples, which is a lot more straightforward than disassembling the sound driver to do it properly. Use this IPS patch: http://stargood.org/files/skitchin_drum_mute.ips (also the game had some copy protection and wouldn't run with the changes at first, so I had to turn that off too)

The hat and tom aren't samples, so you'll still need to mute whichever channel those are on.

Oh. My. God. You are the freakin man! I can't believe this. Thank you so much! I'll try the patch out as soon as I am around my computer again and I'll be sure to report back. I'll also be sure to credit you every time I play my Skitchin' Medley!

Also, thank you to everyone else that shared their expertise as well :)

December 09, 2018, 03:17:28 pm - (Auto Merged - Double Posts are not allowed before 7 days.)
Just patched the game with your patch and I have successfully logged all of the vgm files that I needed and managed to silence all other percussion as well. I can't thank you enough Supper! I may end up recording my medley and throwing it up on Youtube as well, so I'll be sure to throw you a link if you're interested in checking it out. And of course, like I said before, you'll always be credited with making this possible :)

I would say this thread can be marked as closed!
« Last Edit: December 09, 2018, 03:19:51 pm by twinparadox »