Acmlm's Board - I2 Archive - General Emulation - NES emu feature
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Disch
Posts: 12/16 |
I think Xodnizel's (FCEU author) latest emu may have a rewind feature like blargg's. The emu used to be called Nintencer, but then he changed the name and for the life of me I can't remember the new name. You might want to look around for that one.
Other than that emu -- I don't think any other one rewinds. |
teh1337g0d
Posts: 22/26 |
Originally posted by Disch
There was a discussion on this on nesdev a while ago, and ideas were thrown around quite well. And in fact blargg made a working rewind feature in his emu (though it's an unreleased personal emu). Complete with matrix-style slowdown before rewinding (and when you let go of rewind, it slows down, the plays normal speed), and backwards music, no jerky missed frames (a la ZSNES's rewind... at least the last time I used it) -- the whole 9 yards.
...
Most of this stuff could be easily user configurable as well -- like the length of time they want to be able to rewind (5 mins is a hell of a lot), how much snapshots/audio to keep buffered... that kind of thing.
Wow that is a technical explanation, and I understood it 0_o
that a pretty cool idea there fella. In all honestly I would be prefectly happy with just a save state every 3 sec that I could go back to bu pressing a button like on ZSNES, but this is a very cool sounding idea.
Anyways, Im sort of disapointed that no NES emu's use this feature but I guess I wasnt really expecting one to be out there. thanks for all the help people! |
Disch
Posts: 10/16 |
There was a discussion on this on nesdev a while ago, and ideas were thrown around quite well. And in fact blargg made a working rewind feature in his emu (though it's an unreleased personal emu). Complete with matrix-style slowdown before rewinding (and when you let go of rewind, it slows down, the plays normal speed), and backwards music, no jerky missed frames (a la ZSNES's rewind... at least the last time I used it) -- the whole 9 yards.
I've been wanting to put one in Schpune, but I hate working on that end of development. If I do cave and make my own front for Schpune down the road (not very likely -- at least not in the near future) -- I definately will make a rewind feature.
The concept isn't too difficult -- and it's very clever. And yes it does use a substantial amount of RAM. But not enough for it to be a big issue (who DOESN'T have an assload of RAM these days?)
- Always be recording a movie.
- Savestate at key times every X frames
- Keep snapshots of the last Y frames
- Keep produced audio of last Y frames stored in a buffer
More Savestates = more RAM, but eased CPU usage on rewind.
More snapshots = MUCH more RAM, but MUCH easier on CPU usage. Some snapshots are definatly needed though.
Old movie data, savestates, snapshots, audio can be deleted once it gets too "outdated". For example, if you want to allow rewinding up to 5 minutes -- then you can trash savestates and movie data after they're 5 minutes old. Snapshots and audio can be deleted much sooner -- like after 1 or 2 seconds.
When the user rewinds, you feed him old snapshots and old audio (played in reverse), while loading a state and running the movie code to produce more snapshots/audio.
Most of this stuff could be easily user configurable as well -- like the length of time they want to be able to rewind (5 mins is a hell of a lot), how much snapshots/audio to keep buffered... that kind of thing. |
HyperLamer
Posts: 8145/8210 |
I think most emulators just make save states in memory every few seconds. Reverse emulation would be incredibly difficult if not impossible. How do you un-jump, un-read, etc? |
Lenophis
Posts: 823/830 |
Originally posted by Darth Coby
How would rewinding work anyway?
Reverse emulation, which would probably require (probably) a rather large amount of RAM to keep track of registers, flags, and whathaveyou to go backwards with the CPU and PPU. All Zsnes does is reset anyway with its rewind feature (it appears to look like a reset anyway). |
Darth Coby
Posts: 1368/1371 |
How would rewinding work anyway? |
Lenophis
Posts: 822/830 |
The front of Schpune I'm working on right now has both fastforward and slowdown, however, good luck ever finding rewind. =\ The front is still in very early beta stages, is kinda buggy, and far from finished. |
teh1337g0d
Posts: 20/26 |
Originally posted by Prier
Fast forward.
Not sure if there's been a modified version of FCEU to do the other two. Not like it's ZSNES.
Bummer... I thought that might be the case. I know of some that do fast forward and hoped that someone had taken it upon themselves to do slowdown or more importantly rewind. ohh well I guess. thanks for answering. |
Prier
Posts: 8313/8392 |
Fast forward.
Not sure if there's been a modified version of FCEU to do the other two. Not like it's ZSNES. |
teh1337g0d
Posts: 19/26 |
Ok. Can anyone tell me if there is an NES emulator with fast forward, rewind and slow motion features? I ask because I dont feel like downloading 100 different emu's to see what has what. |
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