Super Mario World VC Dump Not Accurate

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rwebster
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Joined: 01 Mar 2021 18:15

Super Mario World VC Dump Not Accurate

Post by rwebster »

Hey folks, apologies if this has come up before but the DB listing for Super Mario World (USA, Europe) (Virtual Console, Classic Mini, Switch Online) is not representative of the data contained in that release of the game. As the dump notes say the ROM was rebuilt using the audio from the USA release, not the audio data actually released for that ROM.

Having dumped 3 digital copies of Super Mario World (Wii VC, Super Smash Bros. Brawl Masterpieces, and 3DS Virtual Console), all using snesrestore to combine the ROM and PCM audio data that was shipped, all 3 of these releases are identical. Below is the hash data for this version of the game.

Code: Select all

Size:	 524288 bytes (512 KiB)
CRC32:	 5D3C0FAE
MD5:	 7DFE85F3C7940C40C32731EFE0DA92AE
SHA-1:	 E23CB10E1BA86BBD1F583D3013A98368AE3301BA
SHA-256: 2C2CCDE435C6A7B7AEA64A856CAEF23178F151FB609C712C856EE4DB9936DA8A
Shouldn't this be the one that's on the site?
rwebster
Posts: 25
Joined: 01 Mar 2021 18:15

Re: Super Mario World VC Dump Not Accurate

Post by rwebster »

Granted this release does have a bad checksum and there are a lot of differences in terms of the data comparison between this release and the original cart. Using IpsAndSum.exe to fix the checksum though, brings the number of differences when compared in a hex editor to just 10, which seems to align with the VC changes of just a few shades of blue.

Between the original cart dump and the one on the DB now for VC, there are just 6 differences.
rwebster
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Joined: 01 Mar 2021 18:15

Re: Super Mario World VC Dump Not Accurate

Post by rwebster »

Also I'm new to all this so I might not understand the reasons and such for the dumps on here :)
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dreimer
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Joined: 14 Nov 2015 13:26

Re: Super Mario World VC Dump Not Accurate

Post by dreimer »

Easy explained. The original audio is flawed and not SNES compatible. The script replaces the PCM run track marker and place holder with the removed original data and we have a working SNES ROM. You might wonder how we can verify that. Easy. Switch ROMs are 1:1 the same used on Wii and SNES Mini, BUT with original Audio intact. So it the ROM output of the script is the same as the Switch Channel uses, we are more than happy to call it verified.

viewtopic.php?f=15&t=3866
viewtopic.php?f=6&t=2822
Here our oddyssey
rwebster
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Joined: 01 Mar 2021 18:15

Re: Super Mario World VC Dump Not Accurate

Post by rwebster »

Thanks a lot for that, clears that up nicely.

So the process of merging the .ROM and .PCM files is flawed because the resulting ROM file would not be playable on real hardware, due to the audio data being dodgey? Although the file is playable in an emulator?

If I wanted to preserve a ROM file that could be played on real hardware, I'm better off taking the .ROM and overwriting the encrypted PCM data with audio from the original ROM dump? That's actually what I started doing at first with Super Mario World and Zelda Link to The Past, before I discovered the tools for merging.

That tool in the thread you linked, the script for creating a proper .SFC, that works on real hardware, would you recommend I use that instead of manually copying and pasting the data in a HEX editor?

Lastly for my own personal library, would you recommend I follow this process rather than using combined .ROM and .PCM files, if I want the best quality ROMs, since the stripped audio is a lossy format anyway?
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dreimer
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Re: Super Mario World VC Dump Not Accurate

Post by dreimer »

ROM and PCM files (aka SFROM file format) won't work on emulator aka it will work as well as on real hardware. Game runs and music is silent as it can't find any audio at all.
The tool you mentioned is lossy and thus was not used at all. And no, the PCM format itself is not really lossy, just the way they made it is not as perfect as the real deal.
Btw, even the tool author says to not use it for archival purposes. The script though just converts back to the sfc file format ROM used before stipping off the audio and putting it in pcm format to skip parts of audio emulation on weaker platforms. The other differences are the things we are looking for, updates and patches to the ROM code itself.
The result of the tool you used works on real hardware, just with lossy music. You are free to use a HEX editor, but the script just.... works.
rwebster
Posts: 25
Joined: 01 Mar 2021 18:15

Re: Super Mario World VC Dump Not Accurate

Post by rwebster »

Cool thanks mate. I can't find a working link to the tool to make a proper SFC without the PCM in that thread. Is there a different link?

Final question, swapping the PCM data in my Link to the Past ROM with the data from the original ROM, it differs by one address compared to your dump on this site for the Switch Online version. This isn't where the PCM data was located though. Any idea what that difference is?

Left is the dump matching the DB (Legend of Zelda, The - A Link to the Past (USA, Europe) (Switch Online).sfc), and the right is my version created from the 3DS VC.

Image
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dreimer
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Re: Super Mario World VC Dump Not Accurate

Post by dreimer »

Switch Online version has one byte difference, yeah. No clue what that change is for.

The script we used is the masterpiece from @mnml: https://gist.github.com/mnml/4c5b53ccb4 ... a3174cda49
source: viewtopic.php?f=6&t=2969&start=15
rwebster
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Joined: 01 Mar 2021 18:15

Re: Super Mario World VC Dump Not Accurate

Post by rwebster »

Thanks for all your help mate :)

Think it's worth putting this 3DS VC version in the DB with the difference from Switch Online?

EDIT

I've just verified that this 3DS version matches the Wii version, once the US ROM audio has been restored to both. So the Switch release is actually different than the previous VC releases by this single byte.
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dreimer
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Re: Super Mario World VC Dump Not Accurate

Post by dreimer »

Was quite sure both were added... Seems like not ^^
So yes, this version is script modded, but not verified by another release like the rest by Switch Online. That should be the reason why it was not added yet. Of course the difference is far away from script modded parts, but still it is not possible to call it verified. If you have access to more VC titles, feel free to verify these too. I am quite sure we did not check all of them on 3DS, Wii, WiiU in all different language variants. So maybe you can find more unknown ones there. If you need any more help, just ask. Not needed that everyone makes the same mistakes when he starts here ^^ Like bad FTP Client used for ROM dump, bad USB cable used for ROM dump, used the wrong tools or used the tools wrong etcetc :P (That was my list btw)
rwebster
Posts: 25
Joined: 01 Mar 2021 18:15

Re: Super Mario World VC Dump Not Accurate

Post by rwebster »

I own quite a few VC titles from 3DS as well as some released on discs like Smash Bros. Brawl, it's only the SNES ones seem to be the tricky ones. I have about 6 SNES ROMs to go through but I've done two so far: Super Mario World which when rebuilt using the USA ROM audio matches the DB, and Zelda Link to the Past which has the 1 byte difference.

EDIT

I've noticed that Kirby Super Star and Kirby's Dream Land 3 don't have VC dumps on the DB, and I have both of these ROMs extracted from Kirby's Dream Collection (imported from the US as it wasn't released here in the UK). I'm going to match the audio data with the US ROM instead of the included .PCM file, and then post the details here.
rwebster
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Joined: 01 Mar 2021 18:15

Re: Super Mario World VC Dump Not Accurate

Post by rwebster »

Ref Kirby's Dream Land 3, I think I know why. When I've copied over the original ROM data over the PCMF encoded data in my ROM, the hash data matches the original cartridge release... But that's weird because it's documented that Nintendo made some colour changes in the VC version.
KingMike
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Joined: 22 Sep 2012 16:36

Re: Super Mario World VC Dump Not Accurate

Post by KingMike »

Some of the changes in VC games are applied by runtime patches rather than direct ROM edits.
rwebster
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Joined: 01 Mar 2021 18:15

Re: Super Mario World VC Dump Not Accurate

Post by rwebster »

Didn't know that Mike, cheers!
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