How can I determine an appropriate frame count for various fighting game animations?

Question

I am currently starting to outline a fighting game I'm doing with a friend. The biggest obstacle for me now is determining frames for every move.

How can I determine how many frames should a quick jab have, a grapple, combination, how many frames of no-action should be allowed between one and second button input for a combo, et cetera? Below is basically the only thing I found:

Startup frames (also called Impact frames) are the time before the move actually makes contact with your opponent, Active Frames are the frames that a attack would occur, and Recovery frames are the time after the hit. You cannot block during all the time intervals, but getting hit during the Impact frames hurts more and can put you in more funky stuff like stuns or even a juggle, depending on the move that hit you.

Answer 1

Haikukane from the discussion I posted on /gamedev on reddit posted a brilliant answer, the whole discussion there is nice, but I'm not sure wether linking to gamedev SE is allowed so I wont do that. Here is his answer tho:

Fighting game player here. For your FASTEST CHARACTERS, The "jab" should have a 3 frame start up, 1 or 2 frames of active time, and 2 frames of recovery. Slower or longer range characters should have incremental increases by 1 or 2 frames on one of those quantities (sometimes two quantities if the move's qualities are strategically advantageous).

Also note you will need to calculate frames for on-hit and on-block. That goes into coding more so than animation, but its important to match the look of moves with the composition of their frame animations (I.e. strong moves have "heft," fast moves have little impact). Please refer to the animations of Darkstalkers 3 for some of the best 2d animations in fighting game history.

If you strictly want to look at frame data (and you really should to understand that the frames are literally how the characters feel) start with Street Fighter IV data. Ryu is a balanced character and is often used as the median for comparison with other characters. Chun Li is a character with both fast moves and hefty moves, due to her limited combo potential (sometimes she is referred to as a zoning character). Cammy has almost all fast moves, but limited range, due to her high combo potential. Lastly I would take a look at T. Hawk for a stereotypical grappler (aka slow) set of frames ( I would avoid coding around zangief's data, because his moves would easily make him over powered depending on the systems in your game).

Grapples: between 3-5 frames of startup for throws, depending on what other moves you want them to counter in your game engine (3 = super strong, should be low range; 5 = medium range, easier to escape. SFIV uses 4 frame startup, but adjusts the throw escape times depending on the character). Active I suppose would be the throw animation, which is at your discretion. Dynamic is best! Use up to a full second and a half if you think of something really cool! Recovery should be long, around 10-14 frames, again depending on how powerful you want them to be. Combo's: The frames are entirely dependent on the frames and hit stun of the individual moves used within the combo. Basic combo systems emphasize low numbers of slower moves that have more individually powerful effects (SFIV), while faster combo systems emphasize high numbers of moves that easily chain into each other. To successfully understand how combo's work (and sorry if this is redundant) please look up the following terms: cancels, links, chains. Frames of action between the moves of a combo: This is essentially automated as it is the blank time created between the intersection of one move's recovery time, the next move's start-up time, and the hit stun the opponent is experiencing. If you try to pre-program static time into your characters, they will feel extremely stiff.

Additionally, this resource was extremely helpful.

Answer 2

It can actually be a mistake to put too many frames into a punch- or kick animation. Just having two phases - limb-drawn-back and limb-extended, works surprisingly well.

Animating the punch with multiple phases between these would make it look smoother, but also slower and will make it lack impact. When you feel you need to improve the quality, add some in-between frames between the normal standing pose and the prepare pose, and then some between the extended-pose and back to the standing pose.

For further reading, here is a tutorial about how to animate attacks. It focuses on pixel art while flash is usually more vector-oriented, but most of it is transferable.

Another recommendation: don't just improvise, work with references. Look at some martial arts videos to get a feeling for posture and balance when martial artists perform their kicks and punches.