Mega Man PC is a better game than people give it credit for, and it's more fun to play fast than slow. So let's play it fast! This submission improves on [2247] DOS Mega Man by DarkKobold in 02:23.55 by 2565 frames (36.597 s or 25%), chiefly thanks to a new trick that skips almost all of Volt Man's stage. In addition, a number of minor tricks, improved strategies, RNG manipulation, and overall clean execution have shortened the other stages by an average of 8%.
The game runs too fast (comically fast) even on the slowest CPU settings of JPC-RR. That's why there are alternative versions of the video. The one marked "soundhack" is the one I recommend to watch. It has been slowed down to a watchable speed while preserving sound effects (more about this in the comments below). It's about 9 minutes long.

Game objectives

2247 this diff
boot 91 64 −27
configuration menu 3 2 −1
title screen 127 120 −7
intro stage 386 375 −11
stage select SVD 146 142 −4
Sonic Man stage 2040 1901 −139
Sonic Man 111 100 −11
stage select _VD 352 344 −8
Volt Man stage 2125 186 −1939
Volt Man 109 98 −11
stage select __D 305 295 −10
Dyna Man stage 1988 1767 −221
Dyna Man 77 52 −25
Wily title cards 363 351 −12
Wily stage 1734 1661 −73
Wily 104 38 −66
total 10061 7496 −2565
As a secondary entertainment goal, I try to make 1-ups drop as often as possible. They are normally a 1/64 chance. I get nine 1-ups to drop from 32 drop-capable kills, though I can only collect five of them without slowing down.

General comments

I used a number of helper programs. The most important of these were a HUD/memory watch script and an optimization script.
The HUD script shows enemy HP and hitboxes, as well as other information scraped from memory. It predicts upcoming RNG values, which is how I knew when a 1-up drop was possible. There are some stage-specific outputs; for example this screenshot shows the HP of the two destructible walls in Sonic Man's stage.
A screenshot of the game with the HUD script activated. Mega Man is in the first room of Sonic Man's stage, jumping to the left after having destroyed the first of two walls. A Frogbot jumps rightward into the wall's explosion. A screenshot of the floating HUD window, showing current values of "Megaman x", "Megaman y", "Megaman dx", "Megaman dy", "Megaman flags", "Weapon counter", "Current sound", "Stage", "RNG →", "Next 1up", "explosion ctr", "wall 1 HP", and "wall 2 HP".
The optimization script automates the testing of many input sequences within a search space you define. It loads a savestate, runs an input sequence, and scores the outcome based on some evaluation function. You may say, for example, "try jumping after between 2 and 5 frames, try grabbing the ladder after between 6 and 10 frames, and rank the outputs by Mega Man's y position." There are more details about the script here. I used it in 46 places, including on all the jumps around corners, which are tricky to optimize manually. The optimization script accounts for the large number of rerecords; some of the runs tried thousands of candidate input sequences. Here is what it looks like, optimizing a jump into a ladder grab:
An animation of Mega Man repeatedly jumping for the same ladder, with minor variations each time.
A consideration in this game is sub-tile alignment. Tiles are 16 pixels wide. Mega Man accelerates in units of 2 pixels per frame, up to a maximum speed of 8 pixels per frame. (There are no subpixels.) Getting damaged sets your speed to −2 pixels per frame. This all means that under normal circumstances, if you have even pixel alignment, it will stay even; and if you have odd alignment, it will stay odd. The only way to change your alignment is to run into a wall (going left makes the alignment even; going right makes it odd) or to grab a ladder (makes it even). Alignment matters for many small optimizations; for example, being 2 pixels behind may allow you to start moving one frame earlier, which gives an advantage of 6 pixels overall. Mega Man moves at 8 pixels per frame at full speed, meaning that you'll have the same half-time alignment in every frame, unless you slow down.
The game's RNG iterates at least once per frame. Random item drops and enemy AI can cause it to iterate more. Each stage has a fixed seed value to which the RNG state is reset when the stage starts; that is, RNG sequences do not carry across stages.
The game is frame-oriented for the most part, running one iteration of the game loop per vertical refresh. But input is interrupt-driven: the global variable representing the current state of input may change in the middle of a frame. Sub-frame inputs are occasionally useful. Pressing and releasing Space in the same frame allows you to shoot on every frame. Pressing or releasing two keys in the proper order is key to switching weapons without losing time on the pause screen. At the stage select and at the beginning of stages, it is sometimes possible to save 1 frame by locating the first input late in the frame before it appears that the game first accepts input.

Boot and configuration menu

This run puts the game files on hard disk HDD rather than HDA (saves 27 frames). It then loads fdconfig.sys, which costs 5 frames here but saves 85 frames in load times later on.
The configuration menu is not frame-oriented, unlike the game itself. It's just a loop that polls a global variable that is set by the keyboard interrupt handler. This means that you can provide inputs much faster than one per frame—but you have to go slow enough that the loop notices one of your inputs before you provide the next one. Input is recognized when a key is released, not when it is pressed, so we start by pressing all the keys we will need, before the menu appears. Then it's a matter of trying each key press/release at a certain time, checking if it was recognized, and going back to slightly increase the delay if not. [2247] DOS Mega Man by DarkKobold in 02:23.55 also used sub-frame inputs here, but this submission spaces the inputs more closely, saving 1 frame.
The stage select screen changes when you release a key, not when you press it. We take advantage of this by pressing and holding Left and Enter well before the stage select screen appears, then releasing both keys at the earliest time when the input is accepted (which will generally be a sub-frame input).

Sonic Man

The jump down to the first room illustrates a recurring theme: pre-jumping before descents, and managing horizontal position to clip corners as early as possible at maximum speed. We jump before reaching the pit so that Mega Man is already moving at his maximum vertical velocity of 15 pixels per frame as soon as the floor is gone. On the way down, we adjust 6 pixels to the right so that, 3 frames later, we can start moving to the right again at maximum speed and just barely avoid bonking Mega Man's head (which would set his horizontal speed to 0). It turns out that in this case an adjustment of 6 pixels is optimal. If we had adjusted only 4 pixels, we would be 2 pixels behind at the same frame; whereas if we had adjusted 8 pixels, we would have bonked, or else be forced to wait an extra frame before starting to move, costing even more time. (Recall that it's not possible to change Mega Man's position by an odd number of pixels except in special situations.) All jumps like this were done using the optimization script to test many combinations of jump height, stop-moving-right time, horizontal adjustment, and start-moving-right time.
The first room in the stage is tricky to optimize. We must destroy two walls, each of which has 8 HP. After a wall is destroyed, it explodes for 28 frames, and during that time, the other wall is invulnerable. (This is the case for all such explosions in the game. There is only one instance of the global explosion object, so the game takes care that no more than one explosion can occur at a time.) During these 28 frames of downtime, we lure the Batvire toward the left to open up some space; then destroy the second wall. We make the final shot land up high, so that Mega Man can walk underneath the second explosion.
The fan shaft is one of very few places in the game with zero or negative gravity. In these places, you can influence Mega Man's vertical speed by pressing the Up and Down keys. Here, we ascend 1 frame faster by pressing Up to instantly accelerate from a speed of −7 (from the jump) to −15, Mega Man's terminal velocity. Without pressing Up, Mega Man's speed goes from −7, to −11, and then to −15.
The next room, with the wall blasters, is the first damage-boost. The Sewer Rat cannot be hit with the Buster except when it stands, and it would take too much time to wait for it to stand. Instead, we destroy one of the wall blasters and take damage from its explosion to walk past it. (Incidentally, this room is also the easiest place to demonstrate that there can only be one explosion at a time. Shoot one wall blaster, then shoot a second while the first is exploding—the second one will not be damaged.)
In the large room, we collect the E Tank that we'll need for the skip in Volt Man's stage. I never knew how to collect this E Tank—it's too high to jump to—until after I had reverse engineered the map format and uncovered one of the game's dirtiest secrets: two of the pipe tiles are actually ladders. The tiles are duplicates of pipe tiles used elsewhere in the stage, but they additionally have the "climbable" bit set. These are the only two such tiles in the game. Here they are highlighted:
A screenshot of the platform holding the E Tank, with the two climbable pipe tiles highlighted.
The wall in the lower right of the large room looks just like the destructible walls in the first room, but it is only vulnerable to Nuclear Detonator (Dyna Man's weapon). Even if we could get through it, it wouldn't save time. When you go that way, the game dynamically erects an indestructible wall (not part of the map data) in the large chamber to prevent you from going any farther.
The underwater sections have reduced gravity (you can jump higher) and horizontal drag, reducing Mega Man's maximum speed to 6 pixels per second. It pays to be above the surface of the water as much as possible. There is a cost, though, whenever Mega Man jumps from a lower to a higher platform: he freezes in place while waiting for the camera to recenter on him vertically. It doesn't happen when jumping down. Camera recentering delay is a concern throughout the game. In a couple of places here I was able to avoid it by only touching a platform for 1 frame, but I couldn't make the same trick work elsewhere.
The Piranhas' spawns are random. While optimizing this section, I ran into situations where I could not avoid a Piranha without slowing down. When that happened, I went back and killed a Sewer Rat to tweak the RNG. Killing a Sewer Rat affects the RNG in two ways: the random drop iterates the RNG once; but also, the Sewer Rats use the RNG while they are alive to decide how long to walk and how long to stand.
The fireball ladder at the end puts a limit, I believe, on how quickly the underwater section can be done. Getting there a few frames earlier would just mean waiting longer to avoid a fireball, unless early enough to hit an earlier cycle.
In the large, dark room filled with Batvires, you'll see a mitigation against vertical camera recentering delay. Jumping at the top of a ladder partially scrolls the camera up, leaving it less distance to move when you touch the ground again. This doesn't help unless Mega Man has a certain amount of headroom, but I do it on all ladders for consistency and because it looks cool. It saves up to 3 frames per ladder.
A split-screen animation comparing Mega Man jumping at the top of a ladder, and not jumping. The jumping one is a tile and a half faster.
There's a little bit of downtime at the disappearing blocks at the end of the stage while we wait for the cycle to finish. It's barely perceptible, but while waiting we adjust 2 pixels to the right—that's as far right as we can go without bonking on the final jump. At normal running speed, Mega Man moves at 8 pixels per frame. Fine adjustments of 2, 4, or 6 pixels are only possible after stopping for at least 1 frame, so we can only use them at forced stopping points like this.
Bosses, like other enemies, have no invincibility frames. The strategy in the Sonic Man fight is to shoot as early as possible, get close as soon as possible, and then shoot on every frame. If you are too far away from Sonic Man, you cannot shoot on every frame because the Buster has a limit of 3 shots at a time. After the battle, we jump in order to shorten the animation of the falling code key.

Volt Man

The skip in Volt Man's stage is possible because the end of the stage is close to the start, separated only by a row of instant-death tiles. Contact with a death tile instantly reduces your health to zero. All spikes and bottomless pits in the game work like this, using specially marked map tiles. Here I've highlighted them:
A screenshot of Mega Man falling toward the death barrier in Volt Man's stage, with the death tiles highlighted.
The trick is that you can pause on the same frame that your health is drained, and use an E Tank to refill your health. I initially thought that it would require four E Tanks, because it takes four frames to pass completely through the barrier. But a small refinement makes it require only one: take damage from a spark on the way down, so that you stagger backwards against the wall. For some reason this means you get hurt only once.
The skip is pretty easy to do even in an RTA run. I wrote a description of how to do it in my run and kavoc has done it in his recent WR runs.
I thoroughly computer-optimized the skip for the TAS. You want to be as far to the right as possible, but not so far that you don't reach the wall after being damaged. You want to drop through the wire early, so you start accelerating as soon as possible, but not so early that the spark doesn't hit you. The optimization script tested 1,500 different combinations of position and timing and settled on this as the best one.
Normally, Raptorbots don't spawn in this part of the level, but in this case they do, because we skipped the trigger that turns them off. It's good for us, too, because we can use them for RNG manipulation. Volt Man can randomly jump either high or low, and a low jump saves 2 frames. We kill one of the Raptorbots to advance the RNG by one step, which is just enough to make Volt Man do a low jump.
The strategy against Volt Man is easy. Let him damage you, and use your invulnerability to get into position to shoot as soon as his shield is gone. It's essential to be close enough that your shots hit on the same frame that you shoot, because you can only have one Sonic Wave onscreen at a time. As a small optimization, you get one free shot before the fight starts.

Dyna Man

The best weapon to use in Dyna Man's stage is Force Field. Not only is it Dyna Man's weakness, it's effective against most of the stage's enemies and hazards, including the nails dropped by Sentry Bees (though not the bees themselves). We switch to Sonic Wave a couple of times to get some 1-up drops, because it reflects backwards after hitting a wall. Switching weapons is free (costs zero time) if done properly, and as long as you are only moving and not trying to do anything else. To switch to Sonic Wave, for example: press S, press Esc, frame advance; release S, release Esc, frame advance. Mega Man will continue moving at full speed during both of these frames.
The jumps over crates in this stage are difficult to optimize. The beginning section of Dyna Man's stage really exercised the optimization script.
Backwards conveyor belts push Mega Man back at 4 pixels per frame, cutting his running speed in half. We use lots of one-frame jumps over backwards conveyors, to touch the ground as little as possible. Forward conveyors do not make Mega Man run faster than his normal speed of 8 pixels per frame, so there's no advantage to landing on them early. On either side of every conveyor belt there are single tiles that you can pass through like air, but which push in the same direction as the conveyor. (Just like the horizontal drag under water in Sonic Man's stage.) You have to know to avoid the extra tiles, or you'll suddenly have lost 4 pixels without knowing why.
The bottomless pits in this stage are not really bottomless. They connect to a later part of the level through a death barrier, just like in Volt Man's stage. If we had another E Tank, we would use it at one of these pits for another major skip. But we have only one E Tank, and it saves more time in Volt Man's stage than it would in this stage. We could farm a second E Tank in Sonic Man's stage (the only other E Tank in the game is in the middle of Volt Man's stage), but it would take more time to do that than it would save here (I think).
At the disappearing blocks over the lava pit, we have to wait a bit for the cycle to develop. Notice how we jump over the high block to avoid a vertical camera recentering delay. We take advantage of the forced wait to adjust 2 pixels to the left, so as to be as far forward as possible once out of the pit. In the next section, the Force Field protects against lava bubbles and acid drops, so the only concern is to avoid bonks and low-to-high jumps which would cause camera recentering.
The hazards on the assembly line at the bottom of the stage are unkillable, and the Force Field does not protect against them. Taking damage is faster than waiting for an opening, as long as you face left before getting hit. When hurt, Mega Man staggers backwards at 2 pixels per frame. Combine that with the conveyor moving at 4 pixels per frame, and you move at 6 pixels per frame while incapacitated from damage, which is still 75% of Mega Man's running speed.
Dyna Man's AI is randomized like Volt Man's, but harder to manipulate. His initial jump is random in both horizontal and vertical components. He can jump toward you with a speed of 4, 5, 6, or 7 pixels per frame, and he can jump upward with a speed of 7, 9, 11, or 13 pixels per frame. His horizontal speed matters because Force Field only works when up close—you want the distance between you and him to close as quickly as possible. His vertical speed matters for the same reason—at higher speeds he jumps higher than you can reach, and you have to wait for him to come down. The HUD script predicts the next few jump velocities, so when you get there you know how many additional RNG values you need to burn as you redo the stage in order to get a favorable jump. In an earlier draft, I had to kill a random Sentry Bee in the middle of the stage. But in this submission, by a lucky coincidence, the two Sentry Bees I kill at the beginning of the stage for 1-up drops provide the right RNG at the end of the stage to get a good jump speed of (7, 9).
Dyna Man's weakness is Force Field, which does 6 damage per hit, requiring 6 hits overall. We can reduce that by shooting with the Buster until we're close enough to use Force Field. There's just enough time to land 4 Buster shots for 8 total damage, which reduces the number of required Force Field shots to 4. To fight with the Force Field, overlap your hitbox with Dyna Man's, and toggle the shot every frame (press and release Space in the same frame).

Wily

It's just good luck that the RNG lines up to make it possible to get three 1-ups in a row in this opening hallway. Because every stage including Wily's starts with its own fixed RNG seed it's perfectly repeatable, no matter what happened in earlier stages. It's not as easy as it looks, though: you have to hit enemies that are not in front of you, which means using the Force Field, and you have to manage the phase of the Force Field (the size of its hitbox depends on its phase) to avoid killing an enemy a frame too early or late.
In the refight against Sonic Man, we get to use his weakness, Nuclear Detonator. This weapon is so slow and awkward—after shooting, you have to wait for 16 frames before you can detonate it—that I initially dismissed it completely. However, I learned from this let's play by Psychedelic Eyeball that it's possible to hit Sonic Man twice with the same shot, which makes it overall faster than the other weapons. I computer-optimized this fight to find the earliest and highest point at which to launch the Nuclear Detonator. Even so, we are left with a few frames of downtime while waiting for the boss to die, which we use to fix our sub-tile alignment to a multiple of 8.
Next, there is some tricky RNG manipulation. Both of the next two bosses have randomized AI—we want a low jump from Volt Man (1/2 chance), and ideally a fast (1/4 chance) and low (1/2 chance) jump from Dyna Man. We are limited in the amount of manipulation we can do; in this section the only options are to wait, or kill a different number of enemies. There are up to 10 killable enemies in the section before Volt Man (the 3 mosquitoes respawn), and you can kill up to 2 Sentry Bees in the section before Volt Man. Unfortunately the RNG values don't quite line up: any way I could find to get the fastest jump from Dyna Man would also leave Volt Man doing a high jump. I settled for a low jump from Volt Man and a second-fastest jump from Dyna Man.
The Volt Man refight is the same as the first fight. After killing the boss, your absolute horizontal position doesn't matter: as long as you are standing on the left half of the screen, the sum of the horizontal camera recentering delay and the time needed to run to the exit door is constant. (The camera moves at the same speed Mega Man does.) The only exception is sub-tile alignment. If Mega Man's position is not a multiple of 8 pixels, the camera will take 1 extra frame to align itself. There's plenty of time to get our sub-tile alignment right while waiting for Volt Man to become vulnerable.
The Dyna Man refight is unlike the Sonic Man and Volt Man refights, in that we're not waiting for something to happen. We can kill the boss just as soon as we can reach him. So in this case Mega Man's absolute horizontal position does matter: it pays to kill him as close to the center of the screen as possible, to minimize horizontal camera recentering delay.
The Force Field makes you immune to the bullets of Sniper Joes and Mets, so the final hallway offers no challenge. The only noteworthy feature is the background tiles that look like yellow light bulbs. These tiles have a zero-gravity property, similar to the fan shaft in Sonic Man's stage in that you can control Mega Man's vertical speed with the Up and Down keys. Here I act like I'm going to fall into a bullet, but then float away.
The final boss is a walking supercomputer called Crorq, revealed in its second phase to be piloted by Dr. Wily. The first phase takes 6 shots of Sonic Wave, which we fire while charging toward the enemy to minimize shot travel time. The second phase goes down 5 frames later: 1 frame to switch weapons, then 4 shots of Force Field. The final micro-optimization is not to release Space after delivering the final blow (saves 0.00067 s).

Other comments

Sound and framerate

The game runs way too fast to be watchable, even on JPC-RR's slowest CPU settings. This was a problem with [2247] DOS Mega Man by DarkKobold in 02:23.55 as well. I think anyone would prefer watching its slowed-down encode over the full-speed video.
The only problem with the slowed-down encode is that it alters the sound effects, making them lower-pitched and longer in duration. To fix this problem, I made a special "soundhack" encode (named after the camhacks in e.g. [3584] Genesis Sonic the Hedgehog 2 by Zurggriff & Aglar in 17:40.08) that hacks the game binary to increase the pitch and decrease the duration of sound effects, so that they sound approximately correct when slowed back down again. You lose some of the high frequencies this way, but it sounds a lot better than just slowing everything down.
The necessary soundhack.py script is in the source code repo and linked on the video encode page. Inside of mm.exe, there is a table of sound effects, each one an array of frequencies. The script multiplies each frequency by a factor of 5, and speeds up the programmable interval timer (PIT) by the same factor of 5. The PIT controls the duration of sound effects and nothing else, so it doesn't affect sync. Why a factor of 5? This was to make the slowed-down encode approximately comparable to the RTA runs at speedrun.com, which use DOSBox with cycles=500. I timed 10 Mega Man blink cycles in JPC-RR and DOSBox, and found that the ratio was very close to 5.
To do the sound hack encode, I ran these commands:
dumpconvert.exe --video-width=640 --video-height=384 --output-x264=megamanpc-soundhack_video.mp4 \
  --video-max-dedup=0 --output-timecodev2=megamanpc-soundhack_times.txt megamanpc-soundhack.jmd
dumpconvert.exe --audio-mixer-attenuate=org.jpc.emulator.peripheral.PCSpeaker-0:10 \
  --output-wav=megamanpc-soundhack_audio.wav megamanpc-soundhack.jmd
ffmpeg -r $((125875/5))/1796 -i megamanpc-soundhack_video.mp4 -i megamanpc-soundhack_audio.wav \
  -af asetrate=$((44100/5)) -ar 44100 -y megamanpc-soundhack.mp4
Or, to embed soft captions in the video,
ffmpeg -r $((125875/5))/1796 -i megamanpc-soundhack_video.mp4 -i megamanpc-soundhack_audio.wav \
  -f srt -i megamanpc-soundhack.mp4.en.srt -af asetrate=$((44100/5)) -ar 44100 -scodec mov_text \
  -metadata:s:s:0 language=eng -y megamanpc-soundhack.mp4
The JPC-RR dumping guide has additional steps to get the frame rate and resolution right for the text-mode parts, but I ignored that in my encodes.

Wall clip

I found a clip/zip, but didn't find a use for it. While climbing a ladder, hold Right and J (jump). At the top of the ladder, release Up, and you'll clip one tile into the solid wall on the right. It doesn't work on the left, and I couldn't extend it past one tile.
An animation of Mega Man reaching the top of the long ladder in Dyna Man's stage, and clipping into the solid tile on the right.

Death warp

Trigger tiles are special map tiles that do something when Mega Man passes over them, for example spawning the enemies for the next room or activating a checkpoint. A minor death warp is possible with a least one checkpoint, where the checkpoint is located a tiny bit farther ahead in the stage. But it's such a small distance, and the death animation is so long, that it doesn't save time. However, I didn't investigate all checkpoints and there may be other opportunities.
An animation of Mega Man entering the bat cave in Sonic Man's stage, dying with F10, and respawning a few tiles down and to the left of where he was.

Trigger tile reentrancy

I found a bug having to do with activating a trigger tile twice. After the fan shaft in Sonic Man's stage, there is a trigger tile in the downward tube that spawns the Sewer Rat and makes the wall blasters start shooting. The Sewer Rat AI is supposed to work like this: walk for rand(32, 64) frames, stand for rand(8, 16) frames, repeat. If you jump straight down into the room (touching the trigger tile only once), that is the behavior you'll see. But if you walk off the edge at an angle (touching the trigger tile twice), you'll instead see the rat walk for about 256 frames before starting its normal cycle. It happens because the rat gets reinitialized after it has already started its AI cycle, and an integer underflow occurs. Abusing the glitch doesn't help here, because you want the rat to stand anyway so it's easier to damage-boost past it. But possibly there are other such bugs in other places.

Out of bounds

After traversing the death barrier in Volt Man's stage, if you go left rather than right you'll end up out of bounds, off the left edge of the stage. There are some invisible solid platforms there. I tried for a while, but didn't find any way to save time or even get back in bounds.
An animation of Mega Man traversing the death barrier in Volt Man's stage using the E Tank trick, and moving left to stand atop the pole at the left of the stage.

Joystick input

I didn't try joystick controls, only keyboard. It's possible that different input code paths could allow different sub-frame input opportunities.

Source and data

The HUD and optimization scripts, as well as other random code and data, are available here:
git clone https://www.bamsoftware.com/git/megamanpc.git

Thanks


feos: Judging...

Sand 2018-12-27: Replaced the encode with one that is 55 frames faster because of shorter load times. The new input file is https://archive.org/download/megamanpc-tas-1_47_298/megamanpc-tas-1_47_298.jrsr.

feos: Replaced the submission file with the above one.
feos: Fantastic movie, accepting as an improvement to [2247] DOS Mega Man by DarkKobold in 02:23.55.
Tier decision is tough. On one hand, the game runs too fast, there's no music, even the slowed down encode is hard to enjoy because this game feels like a sloppy hack. But it's a major improvement and the feedback really was good. I dare to upgrade this movie to Moons despite the fact that the old run is in Vault.
Note to publisher: I'm still waiting for the author to reply regarding this movie's author name.

Sand 2019-01-02: Is it too late to replace the input file again? I tested the late discovery made in the forum, of loading fdconfig.sys but declining all the options, and it saves another 25 frames in load times. No gameplay changes. The new input file is https://archive.org/download/megamanpc-tas-1_46_941/megamanpc-tas-1_46_941.jrsr.

feos: Replacing and keeping as accepted.
The name question has been resolved and this movie is ready for publication, with just the real name. The site doesn't seem to support lack of nickname on some pages, so I'm unsure about that field in the submission. When the submission gets published, it won't appear on the main page, only among published submissions, where both names can be seen, so I'm removing the nickname as the author preferred initially.
Dacicus: Processing...


TASVideoAgent
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This topic is for the purpose of discussing #6192: Sand's DOS Mega Man in 01:46.94
Active player (378)
Joined: 9/25/2011
Posts: 652
I've been looking forward to this submission for quite a while. What an amazingly high quality TAS, especially considering it's your first one here! One "Hell yes!" vote from me. :)
Editor, Player (69)
Joined: 6/22/2005
Posts: 1050
I've also been looking forward to this. Great work with all of the time savings! Yes vote.
Current Projects: TAS: Wizards & Warriors III.
Editor, Skilled player (1438)
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Excellent work, and the amount of effort that was put into the submission itself is nothing short of impressive. Yes vote.
Challenger
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Never played this game, but watched the previous run for the first time back from 2011. Watched your progress since you posted that Volt Man skip, and also seeing this submission, you put much much effort with this "bad" game. Nice to see how the other weapons being usable, especially when an "useless" weapon proves wrong. Yes vote.
My homepage --Currently not much motived for TASing as before...-- But I'm still working.
EZGames69
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So I guess no one submitted this?
[14:15] <feos> WinDOES what DOSn't 12:33:44 PM <Mothrayas> "I got an oof with my game!" Mothrayas Today at 12:22: <Colin> thank you for supporting noble causes such as my feet MemoryTAS Today at 11:55 AM: you wouldn't know beauty if it slapped you in the face with a giant fish [Today at 4:51 PM] Mothrayas: although if you like your own tweets that's the online equivalent of sniffing your own farts and probably tells a lot about you as a person MemoryTAS Today at 7:01 PM: But I exert big staff energy honestly lol Samsara Today at 1:20 PM: wouldn't ACE in a real life TAS just stand for Actually Cease Existing
Challenger
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EZGames69 wrote:
So I guess no one submitted this?
Means author's nickname.
My homepage --Currently not much motived for TASing as before...-- But I'm still working.
Editor, Expert player (2071)
Joined: 6/15/2005
Posts: 3282
I find that the normal encode is too fast and the slowed encode too slow. Is there one at a speed that is intermediate to the two? Anyway, nice find on skipping Voltman's stage.
Sand
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FractalFusion wrote:
I find that the normal encode is too fast and the slowed encode too slow. Is there one at a speed that is intermediate to the two?
There's a speed control on the video player. At 2x it is about 28 fps. For reference, the slow encode is 14 fps and the full-speed encode is 70 fps. For a proper encode, you would have to run the soundhack.py script with a different multiplier, import a new disk image, make a new dump, and pass an altered framerate to ffmpeg.
Post subject: Loading fdconfig.sys saves 55 frames
Sand
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Sand wrote:
This run puts the game files on hard disk HDD rather than HDA (saves 27 frames) and skips fdconfig.sys and autoexec.bat (saves 5 frames), as recommended by the JPC-RR documentation.
Sand wrote:
You'll notice in the table of splits that the time between stages—title screen, stage select, and Wily intro—are a few frames slower compared to [2247] DOS Mega Man by DarkKobold in 02:23.55. I investigated but was not able to figure out why. Initially I thought it was because I put the game files on HDD rather than HDA, but I also tried putting the files on HDA and it only made the boot slower, without speeding up the between-stages times.
I finally figured out why my load times were longer than in [2247] DOS Mega Man by DarkKobold in 02:23.55. It's because DarkKobold ran fdconfig.sys during boot and I did not. Running fdconfig.sys costs 5 frames, but for whatever reason it saves 60 frames in load times later in the run. An updated encode (along with input files etc.) is here: https://archive.org/details/megamanpc-tas-1_47_298 The gameplay is the same as in the initial submission; the only difference is fdconfig.sys and shorter load times. Is there a way to replace the submission with this update? FractalFusion, just for you I made a 30 fps encode. That one should be roughly comparable in framerate with the slow encode of [2247] DOS Mega Man by DarkKobold in 02:23.55. Only the slowest encode has captions. The updated table of splits:
#2247thisdiff
boot9164−27
configuration menu32−1
title screen127122−5
intro stage386375−11
stage select SVD146145−1
Sonic Man stage20401901−139
Sonic Man111100−11
stage select _VD352351−1
Volt Man stage2125186−1939
Volt Man10998−11
stage select __D305301−4
Dyna Man stage19881767−221
Dyna Man7752−25
Wily title cards363357−6
Wily stage17341662−72
Wily10438−66
total100617521−2540
Post subject: Re: Loading fdconfig.sys saves 55 frames
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Sand wrote:
FractalFusion, just for you I made a 30 fps encode. That one should be roughly comparable in framerate with the slow encode of [2247] DOS Mega Man by DarkKobold in 02:23.55. Only the slowest encode has captions.
Thanks! By the way, do you know why running fdconfig.sys saves 55 frames? Is it something that can be applied to other DOS games?
Post subject: Re: Loading fdconfig.sys saves 55 frames
DrD2k9
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FractalFusion wrote:
Sand wrote:
FractalFusion, just for you I made a 30 fps encode. That one should be roughly comparable in framerate with the slow encode of [2247] DOS Mega Man by DarkKobold in 02:23.55. Only the slowest encode has captions.
Thanks! By the way, do you know why running fdconfig.sys saves 55 frames? Is it something that can be applied to other DOS games?
I don't know the exact reason, but fdconfig.sys contains a number of lines that mostly deal with memory usage. It's likely that processing fdconfig.sys allows the PC to use memory more efficiently thus minimizing the loading times later on in the run. Another possibility is the FILES=40 line. This allows DOS to utilize 40 files at once. I don't know how many it would be able to use without this line. (I have read that 30 is actually a more efficient number than 40 for this line). For reference, here are the contents of the fdconfig.sys file in the freeDOS floppy image. shell=cmd80x86.com command.com /k autoexec.bat dos=high device=himem.exe lastdrive=z buffers=20 files=40
Post subject: Re: Loading fdconfig.sys saves 55 frames
Sand
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DrD2k9 wrote:
FractalFusion wrote:
By the way, do you know why running fdconfig.sys saves 55 frames? Is it something that can be applied to other DOS games?
I don't know the exact reason, but fdconfig.sys contains a number of lines that mostly deal with memory usage. It's likely that processing fdconfig.sys allows the PC to use memory more efficiently thus minimizing the loading times later on in the run. Another possibility is the FILES=40 line. This allows DOS to utilize 40 files at once. I don't know how many it would be able to use without this line. (I have read that 30 is actually a more efficient number than 40 for this line).
Yes, I am not sure, but I suspect it is for one of those reasons: high memory, FILES, or possibly BUFFERS. I know that the memory addresses changed, because I had to update my scripts. This page says BUFFERS controls "the number of disk buffers that will be available for use during data input," which sounds like it could affect disk load times. The boot prompts, for each line of fdconfig.sys, whether you want to run it. I copied the choice of lines from [2247] DOS Mega Man by DarkKobold in 02:23.55 and didn't experiment with alternative selections. It was to say Y to every line, except don't run autoexec.bat.
dos=high[Y,n]?Y
lastdrive=z[Y,n]?Y
buffers=20[Y,n]?Y
files=40[Y,n]?Y
device=himem.exe[Y,n]?Y
shell=cmd80x86.com command.com /K autoexec.bat[Y,n]?N
A:\>\autoexec.bat [Yes=ENTER, No=ESC] ? n
I'm not able to do any tests just now, but after a few days I can try running lines of fdconfig.sys in isolation and see if there is a single one that affects load times. The game doesn't open very many files at once. I would guess that it has a maximum of 1 or 2 open file handles at a time. While loading a stage, it opens 4 files (.bin, .frm, .scn, .blk), but it closes one before opening the next; unless, of course there is a file handle leak I didn't notice, or some other detail I misunderstood.
Post subject: Re: Loading fdconfig.sys saves 55 frames
Sand
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Sand wrote:
I'm not able to do any tests just now, but after a few days I can try running lines of fdconfig.sys in isolation and see if there is a single one that affects load times.
I ran some tests at Post #479329 with the surprising outcome that loading fdconfig.sys and saying N to every line is faster than skipping fdconfig.sys with F5, and even faster than loading fdconfig.sys and saying Y to every line. I don't know why it is so. I only tested the title screen, but:
  • Skip fdconfig.sys with F5: 129 frames
  • Run fdconfig.sys, say Y: 122 frames
  • Run fdconfig.sys, say N: 120 frames
DrD2k9
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Those are interesting (and rather strange) results of your testing. It makes me wonder what else may be affected in the run. Unfortunately, this likely isn't something than can be generalized across all DOS games simply due to the insane variety of programs for DOS.
Post subject: Re: Loading fdconfig.sys saves 55 frames
Sand
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Sand wrote:
I ran some tests at Post #479329 with the surprising outcome that loading fdconfig.sys and saying N to every line is faster than skipping fdconfig.sys with F5, and even faster than loading fdconfig.sys and saying Y to every line. I don't know why it is so. I only tested the title screen, but:
  • Skip fdconfig.sys with F5: 129 frames
  • Run fdconfig.sys, say Y: 122 frames
  • Run fdconfig.sys, say N: 120 frames
I reworked the whole run with this change, and it saves an additional 25 frames total.
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Nice! Are you planning to do some further tests and checks before we actually publish this?
Warning: When making decisions, I try to collect as much data as possible before actually deciding. I try to abstract away and see the principles behind real world events and people's opinions. I try to generalize them and turn into something clear and reusable. I hate depending on unpredictable and having to make lottery guesses. Any problem can be solved by systems thinking and acting.
Sand
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feos wrote:
Nice! Are you planning to do some further tests and checks before we actually publish this?
No, unless I get some sudden inspiration, I'm not planning to do any more tests.
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Awesome work, good to see one of my runs get slaughtered. Are you going to attempt Mega Man 3 PC? It definitely needs a TAS as well. Also, I support the move to Moons. This run is actually more interesting and clean than the shitty predecessor movie.
Sage advice from a friend of Jim: So put your tinfoil hat back in the closet, open your eyes to the truth, and realize that the government is in fact causing austismal cancer with it's 9/11 fluoride vaccinations of your water supply.
Post subject: Re: #6192: David Fifield's DOS Mega Man in 01:46.94
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TASVideoAgent wrote:
If we had another E Tank, we would use it at one of these pits for another major skip. But we have only one E Tank, and it saves more time in Volt Man's stage than it would in this stage. We could farm a second E Tank in Sonic Man's stage (the only other E Tank in the game is in the middle of Volt Man's stage), but it would take more time to do that than it would save here (I think).
How easy is it to exit a completed level? Does the E tank reappear on death?
A hundred years from now, they will gaze upon my work and marvel at my skills but never know my name. And that will be good enough for me.
Post subject: Re: #6192: David Fifield's DOS Mega Man in 01:46.94
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Ferret Warlord wrote:
How easy is it to exit a completed level? Does the E tank reappear on death?
You can't return to levels that you've completed. However, I just verified using DOSBox that the E-tank in Sonic Man's stage respawns after a game over but not after a regular death. You don't even have to return to the level select screen after the game over. Just choose to continue--which actually means to start from the beginning of the level--and you can farm another tank. EDIT: This was already addressed by Sand here and here.
Current Projects: TAS: Wizards & Warriors III.
Post subject: Re: #6192: David Fifield's DOS Mega Man in 01:46.94
Sand
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Ferret Warlord wrote:
TASVideoAgent wrote:
If we had another E Tank, we would use it at one of these pits for another major skip. But we have only one E Tank, and it saves more time in Volt Man's stage than it would in this stage. We could farm a second E Tank in Sonic Man's stage (the only other E Tank in the game is in the middle of Volt Man's stage), but it would take more time to do that than it would save here (I think).
How easy is it to exit a completed level? Does the E tank reappear on death?
You can't re-enter a completed stage. The E Tank doesn't respawn on every death, but only on a continue (when you run out of lives and it forces you to start from the beginning of the stage or choose another stage). You have to die 3 times to make the E Tank respawn. Dying is pretty fast because you can suicide with Esc+F10. The death animation lasts about 65 frames, and it takes about 300 frames to reach the E Tank. So while the first E Tank is nearly free, each additional E Tank costs 3×65 + 300 = 495 frames. The skip in Dyna Man's stage would save a max of about 415 frames (probably less because you have to wait for a bee to damage you). It's close, but not quite worth it. I reached these figures by reading frame numbers off of my run.
  • start Sonic: 703
  • collect E Tank: 1001
  • above Dyna pit: 3870
  • below Dyna pit: 4285
There's another potential avenue to explore. Lizstar, who will be running the game at AGDQ next week, had a run where, in the corridor before the Volt Man refight, there was apparently no collision with enemies. The Force Field would normally kill the Met and the Spydroborgs, but she just walks right through them. https://www.twitch.tv/videos/351849325?t=01h40m58s I vaguely the same thing happening to me, but at the time I dismissed it as a bug in the enemy AI in this corridor. (Similar to how, in the Volt Man refight, contact with the shield staggers you but does 0 damage.) But it only happens sometimes, and I haven't been able to reproduce it. (Since it happens right after the Sonic Man refight, I wonder if it has something to do with the camera desync glitch that DarkKobold noted.) Anyway, if the glitch has something to do with collision, there's a chance that it could avoid collision-based death.
Sand
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DarkKobold wrote:
Awesome work, good to see one of my runs get slaughtered.
Thanks :) Your run was one of the first things I looked up when I started to get into this game.
DarkKobold wrote:
Are you going to attempt Mega Man 3 PC? It definitely needs a TAS as well.
No, I don't think so. I looked a little bit at the code and it seems to be a rather different game (different engine and file compression), so I don't know if much of my knowledge would transfer. Which, by the way, I'm hoping to make a GameResources page to present what are now just fragmentary notes in my source code. Stuff like memory addresses, the RNG, and enemy AI.
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Good to know! Enjoyed regardless.
A hundred years from now, they will gaze upon my work and marvel at my skills but never know my name. And that will be good enough for me.
Post subject: Movie published
TASVideoAgent
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This movie has been published. The posts before this message apply to the submission, and posts after this message apply to the published movie. ---- [3888] DOS Mega Man by Sand in 01:46.94