Redoing ZMV but want input

[pagefault]

First of all this is not an open thread for feature requests I want only input on what I am working on. Any other posts to this thread requesting features will be deleted automatically.

Now I am in the process of fixing the ZMV support in ZSNES but I would like input on the following issues:

1) What would you consider a reasonable ZMV size for a 10+ hour movie?
2) If an auto chapter function is added what intervals should a chapter be made, this will allow you to skip through a movie much faster.
3) Would you have a problem if your system was required to play games at 60fps (50fps for PAL) to play back movies properly?
4) How important is a system of authenticity so movies can be guaranteed unaltered and cheat free?
5) Would you like to be able to use movies from other emulators if time permits.

I look forward to your input.

[grinvader]

1) What would you consider a reasonable ZMV size for a 10+ hour movie?

Some megs are acceptable, and with only one state, 30+ hours movies are compressible to some hundreds of kB, so that shouldn't be a problem.

2) If an auto chapter function is added what intervals should a chapter be made, this will allow you to skip through a movie much faster.

At best, user-defined. If not, ~5 minutes or slightly more.

3) Would you have a problem if your system was required to play games at 60fps (50fps for PAL) to play back movies properly?

No problem on my end.

4) How important is a system of authenticity so movies can be guaranteed unaltered and cheat free?

Don't spend too much time on that.

5) Would you like to be able to use movies from other emulators if time permits.

Spend even less time on that than on #4.

Question, somewhat related to #2 and #3:
Will it still be possible to use Fast Forward during playback ? If yes, then 15 minutes intervals between chapters will be enough.

[Dead]

1) What would you consider a reasonable ZMV size for a 10+ hour movie?

1. I think it's OK to have up to 500k per hour, so a ten hour ZMV would be around 5 MB.

2) If an auto chapter function is added what intervals should a chapter be made, this will allow you to skip through a movie much faster.

2. Chapter automatically made every 10 minutes. Because of fast forwarding, chapters don't need to be divided into tiny little pieces.

3) Would you have a problem if your system was required to play games at 60fps (50fps for PAL) to play back movies properly?

3. No. The small number of people who can't possibly run at a full frame rate still can use older versions of ZSNES to run old ZMVs, like they have already been doing for years.

4) How important is a system of authenticity so movies can be guaranteed unaltered and cheat free?

4. It would be a nice feature to have, but on a scale of 1-10 of how important it is, I would put it only at 5.

5) Would you like to be able to use movies from other emulators if time permits.

5. I don't think it is that important for ZSNES to be able to play movies from other emulators. I'd feel better if the time it would take to develop that feature instead be used for fixing game compatibility, sound, etc.

[xamenus]

Nice ideas, though I'm not that interested in #5. I suppose I agree with grinvader and Syvalion on 1-3.

#4: I suppose that might be interesting, although I wouldn't request such a feature myself.

[Oblivion]

1) As long as it isn't huge, I'll probably be fine with whatever size.
2) Auto chapter...maybe every 15 mins with fastforward working, 5 without.
3) I wouldn't have a problem here.
4) Not too important to me personally.
5) I'd stick this in very low priority.

[Kagerato]

1) What would you consider a reasonable ZMV size for a 10+ hour movie?
2) If an auto chapter function is added what intervals should a chapter be made, this will allow you to skip through a movie much faster.
3) Would you have a problem if your system was required to play games at 60fps (50fps for PAL) to play back movies properly?
4) How important is a system of authenticity so movies can be guaranteed unaltered and cheat free?
5) Would you like to be able to use movies from other emulators if time permits.

I look forward to your input.

#1 -- As much as a megabyte per hour is acceptable size for me. I have come across extremely few movies that last more than two hours.

#2 -- Agree with grinvader...user-defined before the recording is made would be best.

#3 -- I personally would not.

#4 -- Significantly important. Below 99%-reliable recording and playback, this would be my second highest desire.

#5 -- Don't bother with that.

[Noxious Ninja]

First of all this is not an open thread for feature requests I want only input on what I am working on. Any other posts to this thread requesting features will be deleted automatically.

Now I am in the process of fixing the ZMV support in ZSNES but I would like input on the following issues:

1) What would you consider a reasonable ZMV size for a 10+ hour movie?
2) If an auto chapter function is added what intervals should a chapter be made, this will allow you to skip through a movie much faster.
3) Would you have a problem if your system was required to play games at 60fps (50fps for PAL) to play back movies properly?
4) How important is a system of authenticity so movies can be guaranteed unaltered and cheat free?
5) Would you like to be able to use movies from other emulators if time permits.

I look forward to your input.

1) I honestly don't care.
2) User-definable like Grin said would be nice, but if not, 1 minutes is good. How is this implemented? A new state save at every chapter?
3) No problem. Even my oldest PC is able to run ZSNES at full speed.
4) I don't care. If you can show which cheats, if any, were active during the recording, that would suffice. Are you planning on adding re-recording support?
5) Wouldn't that be frought with timing perils? It would be nice, but would be last thing I'd look for, except for #4.

[grinvader]

4) I don't care. If you can show which cheats, if any, were active during the recording, that would suffice. Are you planning on adding re-recodring support?

Yes.
See, that's the issue:

You made a re-recorded movie using slowmo and keycomboes. This information is stored in the ZMV, so that people will know, upon load, that you have re-recorded 32456 times, used slowmotions 50%, 10% and 5%, and 7 different key comboes.

But someone can 'cheat' - I'm not talking about the re-records or other features, but about hiding their use.
A simple hack can reduce the number of re-records, and you can pretend you did a perfect movie, in a mere 4 re-records or even less, without using slowmo nor any key combo at all.
This is what feature #4 will prevent: Pure-movies fakers.

[Noxious Ninja]

4) I don't care. If you can show which cheats, if any, were active during the recording, that would suffice. Are you planning on adding re-recording support?

Yes.
See, that's the issue:

You made a re-recorded movie using slowmo and keycomboes. This information is stored in the ZMV, so that people will know, upon load, that you have re-recorded 32456 times, used slowmotions 50%, 10% and 5%, and 7 different key comboes.

But someone can 'cheat' - I'm not talking about the re-records or other features, but about hiding their use.
A simple hack can reduce the number of re-records, and you can pretend you did a perfect movie, in a mere 4 re-records or even less, without using slowmo nor any key combo at all.
This is what feature #4 will prevent: Pure-movies fakers.

Well, then, have ZSNES append a checksum to the file. It still won't prevent faking, but will make it harder.

No matter what DRM you add, a determined person will still be able to fake it.

[Kagerato]

No matter what DRM you add, a determined person will still be able to fake it.

There are certain measures so difficult to circumvent that no one in their right mind would try, and anyone who succeeded would deserve the "glory".

A checksum or cyclic redundancy check is far too simple, in my opinion.

[Nach]

No matter what DRM you add, a determined person will still be able to fake it.

There are certain measures so difficult to circumvent that no one in their right mind would try, and anyone who succeeded would deserve the "glory".

We tossed some ideas back and forth on IRC. Every idea proposed I can hack in a few minutes at the most. Perhaps you could suggest I'm not in my right mind, whatever.

If we do do this, I'll probably be whipping up multiple levels of insanity which probably wouldn't faze me :/

[Noxious Ninja]

No matter what DRM you add, a determined person will still be able to fake it.

There are certain measures so difficult to circumvent that no one in their right mind would try, and anyone who succeeded would deserve the "glory".

A checksum or cyclic redundancy check is far too simple, in my opinion.

Look at it this way: no matter what you do, ZSNES is open source. All someone has to do is look at the source code to see how the protection is done. It's not worth it.

[Kagerato]

We tossed some ideas back and forth on IRC. Every idea proposed I can hack in a few minutes at the most. Perhaps you could suggest I'm not in my right mind, whatever.

Aye; I was there.

If we do do this, I'll probably be whipping up multiple levels of insanity which probably wouldn't faze me :/

Seems like you're looking at the problem from the internal perspective, rather than the external. Of course if you understand how any security system works already it will be easy to circumvent.

The challenge always lies in figuring out the system's exact parameters and how they inter-operate. If you can crack such a system without the source code in just a few minutes, it seems to me you could be making some big bucks with such skills.

Look at it this way: no matter what you do, ZSNES is open source. All someone has to do is look at the source code to see how the protection is done. It's not worth it.

Experience teaches us that open source increases security, rather than decreases it. It's merely a matter of finding the right protection scheme for the job.

[AspiringSquire]

1) What would you consider a reasonable ZMV size for a 10+ hour movie?
2) If an auto chapter function is added what intervals should a chapter be made, this will allow you to skip through a movie much faster.
3) Would you have a problem if your system was required to play games at 60fps (50fps for PAL) to play back movies properly?
4) How important is a system of authenticity so movies can be guaranteed unaltered and cheat free?
5) Would you like to be able to use movies from other emulators if time permits.

1. This is not an issue for me. Whatever makes it work is good enough. (No gigabytes though. )
2. Anything between 5 and 10 minutes would be best, I think. A nice, round 8 minutes would be great for the binary entertainment value.
3. Well, I don't like the thought of this, since it seems like that would cause desyncing if ZSNES suddenly gets choppy, even if only briefly, due to system processes in the background. Then there is the problem slow computers would have, if auto-frameskipping is disruptive to movie playback. Don't disable movie playback on rusty hardware if you can avoid it!
4. This would be ideal as far as I'm concerned; I'd almost expect it. As long as you can know whether someone cheated or not while making the movie, I'd be satisfied. ("Cheating" doesn't necessarily include re-recording.)
5. I deem this totally unnecessary. I don't use other SNES emulators, except for occasional testing. Why bother when I have ZSNES?

[Noxious Ninja]

Experience teaches us that open source increases security, rather than decreases it. It's merely a matter of finding the right protection scheme for the job.

Except with DRM, which relies exclusively on security through obscurity. Even if you have ZSNES digitally sign the movies, you still have to include the private key with the program, which means anybody can pretend to be ZSNES and sign a modified version themselves.

[Phil]

1) What would you consider a reasonable ZMV size for a 10+ hour movie?

I don't see any objection even if file size is 10MB.

2) If an auto chapter function is added what intervals should a chapter be made, this will allow you to skip through a movie much faster.

Personally, I think it should be manual.

3) Would you have a problem if your system was required to play games at 60fps (50fps for PAL) to play back movies properly?

By far, I am not against that. In fact, it must have that feature.

4) How important is a system of authenticity so movies can be guaranteed unaltered and cheat free?

I think it's pointless. Anyway, since Zsnes is an open source project, if someone got the will to cheat people, he can.
Zsnes is not an official emulator to make speedrun and IMO, movie file should be easily hex-editable with re-recording feature allowed. So there will be no more problem about cheating since it's pointless of cheating with that kind of feature.

5) Would you like to be able to use movies from other emulators if time permits.

It would be nice but can you guarantee perfect syncronisation. I am sure not because games are emulated differently. What would be nice to have is a separate software that can convert movie file like Nesmock.

[creaothceann]

1) What would you consider a reasonable ZMV size for a 10+ hour movie?

Well, I wouldn't bother with downloading a 10h movie if its compressed size is 50 MB or more.

2) If an auto chapter function is added what intervals should a chapter be made, this will allow you to skip through a movie much faster.

Manually would be best, either before recording or (even better) during recording. Otherwise 10 min. if fast-forward doesn't break it, 5 min. if it does.

3) Would you have a problem if your system was required to play games at 60fps (50fps for PAL) to play back movies properly?

Some uni PCs here (P4, 1.5 Ghz) choke on DX or OGL games occasionally. Maybe because of the network, or because they have a lot of programs in the background.
That could be a problem, but then I don't watch that many movies.

4) How important is a system of authenticity so movies can be guaranteed unaltered and cheat free?

Don't waste time on it. But a text field (for each chapter?) would be nice; the author of the movie could list the cheats there. I think the "movie-recording community" will find it out anyway, eventually.

5) Would you like to be able to use movies from other emulators if time permits.

A converter would be nice, but personally I'd download other emulators if I want to watch their movies.

[Ichinisan]

1) What would you consider a reasonable ZMV size for a 10+ hour movie?

Is 15MB reasonable? I'm pretty sure that JMA or any solid compression would find a lot of similarities in the savestates taken for each chapter.

2) If an auto chapter function is added what intervals should a chapter be made, this will allow you to skip through a movie much faster.

Every 30 seconds.

3) Would you have a problem if your system was required to play games at 60fps (50fps for PAL) to play back movies properly?

Yes. Emulation should be an isolated environment that is not affected by outside factors. If it is affected by the speed of the system, then it's not done properly.

4) How important is a system of authenticity so movies can be guaranteed unaltered and cheat free?

Not very important. It would be nice if there was on-screen notification of when cheats were enabled/disabled during playback. The description of a memory address could be customized by the creator of the ZMV.

5) Would you like to be able to use movies from other emulators if time permits.

Only if input can be standardized. No source of input should be overlooked, including the initial state of SRAM. It would be nice if the movie file contains data about the ROM image that was used to create it. Interleaved/deinterleaved, header or no header, it shouldn't matter if the CRC of the game data matches. If it doesn't match, it should still be possible to play back, but a notification warning should be displayed.

[creaothceann]

4) How important is a system of authenticity so movies can be guaranteed unaltered and cheat free?

Not very important. It would be nice if there was on-screen notification of when cheats were enabled/disabled during playback. The description of a memory address could be customized by the creator of the ZMV.

Someone could use programs like gw32 to edit ZSNES. I've done that with emulators that don't offer a cheat system...

[AspiringSquire]

2) If an auto chapter function is added what intervals should a chapter be made, this will allow you to skip through a movie much faster.

Manually would be best, either before recording or (even better) during recording.

I was thinking that, too, after I had posted. I figured others would have the same idea. Thanks for backing me up!

And for the full-speed requirement, I was thinking that maybe, rather than recording the input based on elapsed time, why not have it based on the number of executed frames? This would include the frames that are auto-skipped, too, if possible.

[AspiringSquire]

3) Would you have a problem if your system was required to play games at 60fps (50fps for PAL) to play back movies properly?

By far, I am not against that. In fact, it must have that feature.

It must have that "feature"? What exactly do you mean by that? It sounds to me more like a limitation than a feature.
Of course the movies will always be able to play at full speed; would you really expect anything less?

[michael flatley]

1) 25MB per hour max
2) Depends on seek time and file size. Obviously total random access of the zmv is ideal, whatever you can accomplish is appreciated.
3) Are you saying that if our system ever drops a frame the zmv playback will be corrupt?
4) Not that important. I've seen months of effort put into features like this and there is either a way around it or people still doubt the valid product. And besides, people can make an avi out of the zmv and just use current versions of zsnes that allow for cheated zmv's. Nobody would know the difference...
5) I am using zsnes for a reason - it is the best snes emulator (in my opinion...) No cross-emu support please.

[pagefault]

1) 25MB per hour max
2) Depends on seek time and file size. Obviously total random access of the zmv is ideal, whatever you can accomplish is appreciated.
3) Are you saying that if our system ever drops a frame the zmv playback will be corrupt?
4) Not that important. I've seen months of effort put into features like this and there is either a way around it or people still doubt the valid product. And besides, people can make an avi out of the zmv and just use current versions of zsnes that allow for cheated zmv's. Nobody would know the difference...
5) I am using zsnes for a reason - it is the best snes emulator (in my opinion...) No cross-emu support please.

Yes it may turn out that way that if a frame is dropped the movie playback is corrupt. Thats why it will be necessary to show all the frames to ensure the movie is played back properly. I am trying to find another way to do this however so this may not be the case in the final code.

[michael flatley]

Isn't it the case that everyone drops a frame now and then? I don't think the new zmv features would be worthwhile if 60fps was required. I hope you can find the other way you are looking at.

[Phil]

3) Would you have a problem if your system was required to play games at 60fps (50fps for PAL) to play back movies properly?

By far, I am not against that. In fact, it must have that feature.

It must have that "feature"? What exactly do you mean by that? It sounds to me more like a limitation than a feature.
Of course the movies will always be able to play at full speed; would you really expect anything less?

It appears I misunderstood the question. Well, I am against that evidently. I thought he means a PAL/NTSC flag in movie file.