Questions/thoughts (long)


Hey folks, I play SSF2T on GGPO quite a bit, but I thought I’d finally sign up here and tap into some people’s knowledge banks on this game because I have quite a few questions. They may actually be unanswerable since we do not have access to the source code. In fact, I would guess Sirlin is the only one who has seen it (since he was involved in HD remix).

Now I should probably preface with the following which may be the direct result of some quirks: 1. I’m playing online exclusively, this means that latency could be the culprit for lots of weirdness, this includes prediction errors. 2. Since I am playing on GGPO, this means the game is emulated and as we know, the game is not emulated 100% accurately (stages have random slowdown, run too fast, etc.) and personally, I think the rom floating around is a bad dump, but that is just me. 3. I am using a non-standard input device (keyboard) which the game was never intended to be played with and may cause problems.

Anyway, to begin then, I use O.Ryu at the moment. I know new is better, but I’m not here to discuss that.

  1. First off, from my experiences, it seems some move priority seems to be random. It could be timing + lag, but here’s what I’ve seen. Playing against zangief, O.ryu’s hurricane kick seems to beat his lariat randomly. I thought it was the height/positioning, but it seems to be different every single time. Sometimes The hurricane kick beats the lariat right when it starts, sometimes it gets shutdown by it. In addition, a jump kick/jumping fierce seems to beat deejay’s jumping kick and guile’s flash kick sometimes, but rarely. So I ask, does anyone know the exact reasoning behind this? I’d love to be able to understand this more.

  2. If someone crosses me up and I block and I try to reversal, I end up attacking the incorrect direction. This also happens if someone does an early jump kick to land behind me, if I go for the throw (and I’ve waited a while), I end up punching in the wrong direction. This doesn’t always happen, but it happens a lot, my timing is just off then? (On another note, the game engine appears to poorly track player positions because you often have cases where players are attacking the completely wrong direction).

  3. Throws seem insanely strong. What I mean is you can throw people out of special moves and supers. You can also walk right through normal attacks and throw people. That just seems totally crazy. When I was playing the dreamcast port of this game, I threw ryu out of a dragon punch (I was ken), how is this possible? It seems that once the game accepts you are going to initiate a throw, it “beats” everything else.

  4. From what I can gather, it seems that the input buffer has some weird problems when initiating moves. The best example I can give is that several times, I did the command for a hurricane kick as I was landing from a jump, and instead, was given a reversal dragon punch. How does down+back+kick translate into a dragon punch? I have no clue, can anyone enlighten me?

  5. The game sometimes double buffers punches or kicks. Like I’ll do down+forward punch for fireball, but instead it does crouching jab THEN fireball. Keyboard buttons are digital whereas the joystick is analog and I think the buttons are too, so it could cause problems.

  6. Late reversal. An example, someone does a jab that initiates block stun, and you do a reversal dragon punch let’s say, but the person immediately followed up with a few more (keeping block stun) and then stops. Then the reversal you did way back comes out and the person is free to do whatever they want. I’m not sure if there is a way around this and it happens seemingly at random and could be due to lag.

  1. I highly doubt the ROMs are bad. The memory test in the test menu passes without any issue. The graphical glitches primarily appear only on nFBA and speed differences affect every emulated game period, not just ST. I don’t know of a single emulated game that runs frame-perfect to its actual console counterpart over a period of time simply because it’s almost impossible to account for all the factors that might affect speed (esp. difficult with hardware slowdown). At least emulated ST runs reasonably the same speed (esp. offline), unlike HF, which is totally off. But of course, having the real arcade version is best.

  2. Timing and hitboxes. You have to understand the concept of a move’s startup, active, and recovery frames. During an attack’s startup, you have all vulnerable boxes that may move around and/or change shape. During activity, your damage hitbox suddenly pops up in front of you and, along with the vulnerable hitbox may move around and/or change shape. During recovery, it’s back to the vulnerable hitboxes. That’s the concept behind why claw and Dhalsim miss c.HP up close: because their attack hitboxes appear far away from their body, far enough that it’s even past the opponent’s vulnerable hitbox. In your example situation, Zangief can always be beaten at the very start of a lariat by just about any aerial move where the attacking hitbox sticks out. After just a few frames afterwards, he must be beat with a high priority air attack. A hurricane kick also has its hitbox moved from back to forward within a few frames so if you have a difference of just 2 frames and 2 pixels, you’ll encounter a different result everytime.

  3. Yes. This has already been discussed in-depth in that recent HDR topic.

  4. Hitboxes. Vulnerable grounded moves are throwable. There’s a point in Ryu’s dp startup where he’s still considered grounded but regains vulnerability where the attacking box shrinks upwards to allow close-up throws by the opponent. The timing to throw him before he goes into the air is too difficult to seriously try though. You should take a look at NKI’s shenanigan’s video: [media=youtube]yY3Yx9mT6Ks[/media]

  5. Are you landing from a crossup or grazing P at all when you’re pressing K? The DP is Ryu/Ken’s highest priority input move so if you pull out any/all of his special motions in 1 fluid motion and press P+K at the end, the DP always comes out. Otherwise, it could be a controller problem. What you’re describing isn’t a known ST issue to my knowledge.

  6. Timing and negative edge. You’re pressing P at df and upon releasing P after hitting f, the game gives you your fireball. Normal joysticks are digital (including all the known optical sticks). They can be 1 of 8 directions plus neutral. Buttons are digital; the game only accepts depressed and non-depressed states for each switch, direction or button.

  7. Timing. It’s actually possible to do the dp motion, have the opponent do a LP or maybe 2 chained LPs for some characters, and still have that motion active when you press P again. Whenever you perform the full motion (with leniency between each direction), there’s also a further leniency before pressing P (about 10 frames worth). In the meantime, if you’re in blockstun and mashing P, you don’t lose your motion leniency (since otherwise, mashing would eliminate the chance of a reversal) and nothing comes out. The frame you’re out of blockstun but maybe on the last frames of your dp motion leniency and press P, the dp will still come out, even if the opponent already got a few moves in-between.


What he said.


Ganelon is the man, big thanks. Your answers are exactly what I was looking for (no sarcasm). By the way, which HDR topic discusses the “attack the wrong way” business? I’d like to read it.

RE: joysticks, I always thought they were analog because doesn’t street fighter 2 have “walking” speed? Guess not then.

RE: Hurricane becoming dragon punch. My layout is ‘A’ is short kick, ‘Z’ is jab punch. Therefore, I may have pressed ‘Z’ without knowing it.

One more thing, you mention that there is a point in Ryu’s dragon that he is considered grounded. Form what I’ve seen, does this also apply to starting up a jump? Because fireballs and other ground moves hit you as you start to go in the air. The fireball sprite appears to move upwards as well after the hit.


jumps also have startup where you are still grounded.


Joysticks: if movement along a direction was analog, pushing the stick a little would result in a slower walking speed than pushing the stick all the way (as in Gran Turismo 4). That’s not even possible with all your normal arcade sticks, much less supported by the game itself. SF2 doesn’t even have acceleration based on the duration of the switch press (as in any Mario game); movement speed in ST after holding a direction from 0-10 frames is the same as movement speed from 60-70 frames.

Jumps: There are pre-jump frames (the bigger characters crouch just before they jump, which is a throwable ground state). Regardless, towards the start of any jump, you leave the ground but are still low enough to get hit by most ground attacks, including projectiles.


Yeah, I always thought sf2 had a slower walking speed based on slightly pressing the joystick forward (analog control), but it doesn’t.


Okay, so we know the reversal window is random, correct? (I’m going off HD remix changelog). Do we know how many milliseconds it differs by (or frames) each time? Obviously it is not truly random, but I’m guessing it varies by one frame.

In addition, specifically when getting up and after getting hit by an attack which causes slowdown, what frames can input be accepted? I’d like to know that especially for an attack causing slowdown because often when I try to input a special move, it only gets my movement but never the attack buttons. For reversaling after being knocked down, I sometimes input an attack but when the character gets up, he is just standing there. Obviously I input the move late, but I’d like to know the window of when input is accepted and then not accepted, I know this cause if you are late you can still get a non-reversal move, but if you wait too long, you get nothing.


Hey, we played on GGPO… ggs man.

Regarding input during slowdown, from what I have read, no input is missed. I believe the only time that input is interrupted is during the startup of a super.


The reversal window is exactly 1 frame from what NKI tested. Any earlier and nothing comes out. Any later and the reversal message doesn’t appear.

As for slowdown, no frames are dropped. However, you can’t just perform the motion with the same timing; if you try to do anything in the middle of slowdown, nothing will happen since nothing is being buffered. As long as you account for the slowdown by entering the motion at the end of the slowdown phase, the move will still come out at the same instance of your recovery.

You can test this with o.Sagat’s low tigers. When they’re blocked, you can easily keep pumping them out without Sagat even getting up. When they hit, just wait until the slowdown is about to clear, enter the motion, and the low tiger will still come out every time at the same fluid rate where Sagat doesn’t get up.


geo i don’t remember playing you, but good games haha.

Anyway, I was thinking about it, if people are so disappointed with HD remix, why hasn’t there been a community led effort to hack and patch the arcade roms with fixes that we’d like to see. I think that would be very possible, like a competition mod of sorts.


You’re missing the point. The Arcade ROM doesn’t need any patches or fixes. The arcade ROM is canon. It is exactly as it should be. Yes I know it has all sorts of wonky shit that can occur… That’s part of the allure of ST.

I’m so glad I bought myself a board so I don’t have to deal with all the crappy ports, and the funky speed changes on Emulators.


I don’t think I’m missing the point. Each iteration of sf2 is a patch. So rather than constantly shelling out money for changes, a mod team can do it. This game it might not be as feasible, but sf4 it should be. See people waited for sirlin to balance stuff and such and paid 15 bucks to get disappointed, when a community could constantly test changes. Obviously the arcade crowd has never really experienced this, like PC games have.


The huge difference here is there is no single entity to control what gets patched and what doesn’t, or what is the official patch for competitive play.

A community driven project would descend into an infinite cycle of pointless bickering, and a single individual would never have enough credit to be allowed to make those kinds of decisions without having official Capcom support like Sirlin did.

Don’t get me wrong, I would love to see ST get hacked and there be a dozen “remixes” floating around to be played for fun or in side tourneys, but it’s never gonna happen for the main competitive scene.

What I really wish would happen however is for someone to create a pallette/music editor for ST.

On an unrelated note: I believe the dumps of ST floating around are a little bit imperfect/corrupt. There’s just too much junk that shows on the screen every so often, and that isn’t present in any other CPS2 dump so it’s not the emulators fault. I would be extra interested in knowing if this stuff is present in phoenix’d copies of the board. It would truly suck to find out that you paid money to have your pcb flashed with a corrupted ROM.

  1. Refer to the 0th point of my first post in this topic.
  2. Plenty of games have graphical distortion on emulators. What exact junk on-screen are you referring to? Please be specific.
  3. No, it’s not in phoenixed copies. If you had a phoenixed copy, you’d see that the startup screen is slightly different from a PCB with normal ROMs.


A lot of those graphical errors show up on the board.

I’ve got a couple on mine and its not Phoenixed. Theres one specific one that shows up in the border of the portraits on the Versus splash when someone joins in. You’ve probably seen it on my cab before


Does o.ryu’s invincible dragon punch not save him from being thrown or am I experiencing prediction errors? Because quite often, for a split second, I can clearly see I am starting up the motion for dragon punch after a tick but I am then immediately thrown. Or does the invincibility start later?


Invincibility and Throw Invincibility are two different traits.

I’m pretty sure theres a few invincible frames in the start that are not throw invincible.

Like the 3 or so frames before the attack goes active I think you’re throwable


It appears on Turbo2 settings that the game counts simultaneous presses as pushing one button one after the other (in a quick manner however). This is the cause of why so often when I do crouch sweep/medium kick->fireball motion, it sometimes completely skips the sweep/medium kick and does the fireball (a lot of the time dragon punch when walking forward).


It seems you are talking about GGPO, or some other online stuff

O.Ryu’s SRK is completely invincible and unthrowable during start up and active (offensive, rising) frames. I am not sure there is a move with absolutely no defensive hitboxes (i.e., invincible) which is throwable before some defensive hitbox shows up. Perhaps Honda’s headbutt, which I know should be used on wake up against grapplers so as to make use of the 13-frame throw invulnerability.

Anyway, what happens is that either lag makes it look like you got a SRK, but in fact you were already getting thrown. It is an inherent problem of online play.

But you should not press two attack buttons at the same time to cancel a normal into a special. At least you do not need to. Anyway, if you do press them at the same time properly, you should always get a punch instead. If not, you might be just kara-cancelling the move. Delaying the QCF+punch input might help getting the hadouken to work. Specially when walking forward, as any shoryuken that is not jab is easily punishable after a forward or roundhouse kick.

I do not believe it would be an issue related to speed 2 only, BTW.