Glitches and emulation errors in Mega Drive, Retrocopy 0.720

Yes, I agree the whole idea of changing Sega Genesis / Mega Drive ROM files extension is a whole mess and should not have been decided in the first place (control freaks, again ;-) ), as you can see in the no-intro threads, it's impossible to find something that suits perfectly to the situation so better leave it how it was initially.

That's said, you can safely handle .GEN and .MD files as .BIN files since I have yet to see a .MD file in interleaved format (supposing this "standard" ever existed, this has never been listed as supported ROM format in any emulator before and the only reference is this old ROM format document, however I think I remember seeing .MGD files floating around 10 years ago).

Anyway, relying on file extension is generally not a good idea, I've seen some .SMD files that were in fact plain .BIN files with bad extension, it's always better to check the ROM internal data to see if it's interleaved or not and if it has an additional header or not. There are plenty ways of doing this, even with headerless files (check for the word "SEGA" at some place, do a quick 68k disassembling, etc)

yes, I understand the difference between data types and file extensions, it's just a pain in the ass to rename roms everytime you import new ones.

Agreed it's not the best situation to rely on extension, but given you can have false positives with heuristics on headerless files it is something groups like no-intro should take into consideration before deciding to do something. This is what happens when you have non programmers or amateurs running things they probably shouldn't.

In my mind people shouldn't be trying to change things when they don't have the capabilities to do it as you end up with half assed solutions that hundreds of other people have to deal with. These people should be working WITH others that CAN offer solutions instead of what's happening now where it's like King Arthur trying to build a rocket to the moon.

Well, it's just file extension renaming to another one nobody never used, I think you are making this a big deal when you should appreciate the effort these people are doing to make accurate list of all existing game dumps. This is the most important in my opinion and they actually have the capability to redump original cartridges (which I don't personnaly, which is why I appreciate people doing it)

Your GAME format (I have the feeling this is what you mean by "others that can offer solutions", am I right ?) is not a bad idea but has its flaws too: there is no way it will ever be the format of choice for ROM distribution, it's too late and should have been discussed years ago when the first groups were starting releasing stuff (a ROM format consortium lol).

The reason a generic solution like this never came up is probably that it is not possible to federate everybody, which is quite logical: as you said this is amateurist hobby, nothing more, and no matter how "professional" you try to make it look, it will remain the same :-)

There are plenty of people dumping ROMs, they aren't the only group. I think most of us appreciate any selfless work people do, my beef is with trying to do things which aren't in your capabilities. I don't think there is necessarily anything wrong with people sticking to what they are good at?



I don't see it being late as a flaw, when the scene was first starting up we didn't have the algorithms we do today either so it wouldn't have been as good. These days we can bundle different files that are relatively the same and get massive space savings, among other benefits.



I think the reason it didn't come up earlier is it's a lot of work to do it right. I've spent months on and off on the problem and Tommy has spent hundreds of hours helping with a good database. Most people aren't willing to devote so much time especially those that are capable. And we have only scratched the service with the SMS, though a lot of that was solving teething issues with certain things and won't necessarily apply to other systems.

I disagree with your opinion about it not becoming more professional. Going forward people are going to expect more and more not less, it's going to force people to be more professional if they want to compete in the same arena. Seeing as people have been working on emulators for a while now (with a massive influx around 2000) I expect the best of these developers to come back eventually and surprise us.

And when they do they aren't going to want to rewrite the wheel I've made. I've been saying for a while now .GAME is ahead of it's time, it's for the next generation not what people are doing these days.

Ralph you added Record input to retrocopy? if still not, please don't add this thing, i've found some problems with this feature in another emulators

No I haven't added it yet. Most emulators have issues with their state saving code which is why you usually get issues with some games in "INPUT RECORD" mode.

RetroCopy has been designed from the start to be very reliant on states (rewinding for instance) and any issues in it are quickly noticed and fixed. That and it also doesn't use any hacks to get things working and is at the cycle level make it much more secure in this regard.

So there should be less of these issues when I do get around to doing it. I'm changing the input system a bit after next version which will accommodate input recording among other things.

So this is not cause issues in Retrocopy

Thanks

I just completely forgot about Sonic Crackers, today i unzip this game and try to run in Retrocopy, and found bug with sprites:

On picture only one hand with ring

I think what feature: High Priority will be useful for stable speed.

I not sure if it not broke something, feature: audio playback rate at 50Hz for PAL Mega Drive will be very useful

I think what in "cut off filter" bugs in high frequency SFX and music, i recorded movie with these bugs (record in Fraps)

http://www.youtube.com/watch?v=BkAbKhqA59I

Nice video. Have you been playing with the cutoff values in the config.xml file? It sounds like a few frequencies are being amplified too great causing distortion.

Thanks.

i use values by default, also try with all sample rates: 22050Hz, 44100, 48000, etc.

Finally i created Sound Test with 3 consoles for Retrocopy: Sega Genesis, Mega Drive 2, Mega Drive 2 clone.

Video record: http://www.youtube.com/watch?v=dWfdf5kWbb8

what a boring video... lol!

It's interesting the differences you've made Sasha. Now if I can add some features to get the authentic looking consoles in there you could make some more interesting videos with those variants! The new 3D sound engine has a lot more flexibility in regards to how sounds come out too with stereo systems for instance.