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mlin

Combining Demos - Possible or Not?

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If the fastest time for each individual level run on COMPET-N was combined into one demo for the whole game, it would be completed in 23 minutes and 42 seconds. Does anyone know if demo-combining is possible?

Thanks in advance.

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Only with special tools, and only if it is planned that way in advance, so that the player has the right stats going into each map (that's how Doom Done Quick was done). It isn't possible to combine ordinary pistol start demos in the way you suggest.

If you want to see Doom2 done really quickly, then I recommend Sedlo's 30uv1617. :) Yes, that is 16 minutes, 17 seconds. It plays back fine with prboom/glboom (but not doom2.exe).

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It would be weird to see a demo patched together of ones that don't fit. Ammo would change, and all that other stuff. and it would be weird watching a different play style being used, unless the demo person is the same.

heh.

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Thanks again Grazza. The first site you gave me was great, but the 16 min run by Marijo uses "illegal" speed-boosting devices. I'm looking for the fastest legitimate time which can be played in Doom II without modifications of any sort.

Edit: whoops. The D2DQ2116.bat (Doom II Done Quick in 21:16 batch executable) is giving me the error message "Failed trying to allocate near-pointers". In Windows XP, both with and without Win 95 compat mode

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that is incorrect, although assisted, Sedlo's run was actually played by a human player; there are no "illegal" moves. Probably the single most amazing demo ever recorded for any FPS game.
and, yes, the 30nm demos are a greater feat of skill, but that in no way diminishes this run.

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Well, exactly what tools did he use to achieve such a time? In other words, what did he do in the demo that he CANNOT do in the regular Doom II? As the demo cannot be played in the original, legit Doom II, I have doubts. I know it's amazing gameplay, but I think something has been done to the modified game engine to make players able to run faster.

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The fastest known "legitimate" time, or a straightforward run through DOOM II on Ultra-Violence, with no editing or re-recording of any kind, would naturally be the fastest movie run. In other words, stx-Vile's 26:57 demo.

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Slow-motion and saves. The only reason it won't play back in Doom2.exe is that it was recorded with TASMBF (necessary to use those features in a multi-level demo), which doesn't have perfect demo compatibility with Doom2.exe.

In principle, everything he does in that demo could be done in Doom2.exe - it would just be insanely difficult. Actually, if you read Sedlo's text-file, you will see how extraordinarily difficult it was even with tool-assistance.

I don't regard TAS demos as a lower form of art than unassisted demos - it's just a different, more "scientific" one.

BTW, I recall Cameron Prosser saying that he considered a time around 13 minutes to be possible in a 30UV TAS run.

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mlin said:

Well, exactly what tools did he use to achieve such a time? In other words, what did he do in the demo that he CANNOT do in the regular Doom II? As the demo cannot be played in the original, legit Doom II, I have doubts. I know it's amazing gameplay, but I think something has been done to the modified game engine to make players able to run faster.


I think it's cool that you are watching these demos. Don't get me wrong. damn, I wish I could do these things.
but there is no 'cheating' in the TAS demos. They are assisted (that means recording with save-games and using slow-motion), but every move had to be 'played' by an actual player with a normal config.
in short, the 16:17 run (though extremely unlikely) could be duplicated without being assisted.

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DEMOn said:

in short, the 16:17 run (though extremely unlikely) could be duplicated without being assisted.

I've just now been wondering how unlikely it would be. If we assume that there are 20 things he does in that demo that only work 1 time in 5 (a conservative estimate, I think), then he'd need to make about 100 trillion non-TAS attempts in order to have a decent chance of a successful recording. Assuming 10 minutes per attempt, that's about 2 billion years.

DEMOn said:

Probably the single most amazing demo ever recorded for any FPS game.

Either that or qdqwav, IMO.

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DEMOn said:

I think it's cool that you are watching these demos. Don't get me wrong. damn, I wish I could do these things.
but there is no 'cheating' in the TAS demos. They are assisted (that means recording with save-games and using slow-motion), but every move had to be 'played' by an actual player with a normal config.
in short, the 16:17 run (though extremely unlikely) could be duplicated without being assisted.


Yep, makes me realize how freakin' much I could improve at Doom. I've been playing for a year now and need at least several hours to beat it :O

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Grazza said:If you want to see Doom2 done really quickly, then I recommend Sedlo's 30uv1617. :) Yes, that is 16 minutes, 17 seconds. It plays back fine with prboom/glboom (but not doom2.exe). [/B]


Off-hand, I can suggest DOOM.EXE. Several Andy Olivera's TAS demos of DOOM[] WADs (e.g. Cleimos2) go out of sync with both DOOM2.EXE and prBoom but play fine with the Ultimate DOOM executable.

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Grimm said:

Saving is all right, but slo-mo ain't cool in my book.

well, it depends upon how you look at it... these are assisted demos where they don't hide the fact they've been assisted.
Ever played DOOM in slow-mo, it doesn't make it all that much easier. :)

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Never_Again said:
Off-hand, I can suggest DOOM.EXE. Several Andy Olivera's TAS demos of DOOM[] WADs (e.g. Cleimos2) go out of sync with both DOOM2.EXE and prBoom but play fine with the Ultimate DOOM executable.


There must be Lost Souls in those demos then. And Doom95 can also be used in most places Doom works and others fail.

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Grimm said:

Saving is all right, but slo-mo ain't cool in my book.

Just view it as a different category of demo. As long it is clearly stated and the extra possibilities given by the different recording method are used to their full, what's the problem?

Never_Again (and myk): This is a TASMBF demo, not TASDOOM or DOSDOOM. It also plays back OK with MBF, of course.

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I just finished watching Sedlo's demo. It's awesome.

I played it using PRBoom; it doesn't work in Doom95.exe as NEVER_AGAIN said.

I wish there could be some kind of a converter that can convert demos between all of the popular source ports.

I'm a newbie at this, but what is "strafe 50"? Sedlo mentions it frequently in his text.

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mlin said:

I wish there could be some kind of a converter that can convert demos between all of the popular source ports.

Not really feasible. A demo is just a recording of the player's actions. The reason a demo recorded with one exe will not generally play back with another is that there are small (or large!) differences in the game physics and the algorithms used to calculate things.

The best we're likely to get is a port that has lots of different compatibility modes, and so can emulate lots of other ports. Prboom is pretty good in that respect for the older exes (indeed, this is one of its main aims), but obviously has no chance with Zdoom, Legacy and jDoom demos.

mlin said:

I'm a newbie at this, but what is "strafe 50"? Sedlo mentions it frequently in his text.

It is the fastest way to run. Strafe 40 is pressing run, move forward and strafe right (or some similar combination). Strafe 50 is pressing pressing run, move forward, strafe right, strafe on and turn right (or some similar combination). You move a bit faster and at a slightly larger angle. It's kind of difficult to control until you've got a fair amount of experience with it and a convenient set-up for implementing it.

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Grazza said:

Never_Again (and myk): This is a TASMBF demo, not TASDOOM or DOSDOOM. It also plays back OK with MBF, of course.


Oh ... My bad, should have read it right the first time.

Strafe 40 is pressing run, move forward and strafe right (or some similar combination). Strafe 50 is pressing pressing run, move forward, strafe right, strafe on and turn right (or some similar combination).


Strafe-40 is normal strafing, when you press either strafe key (default keys are "," and ".", IIRC). That way you move sideways at 40 units/sec. Your strafe-50 description is correct, except the turning part: you cannot turn while strafe-50ing. That's what makes it hard to execute.
on the other hand, you do get a 10 unit/sec boost.

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mlin said:

I'm a newbie at this, but what is "strafe 50"? Sedlo mentions it frequently in his text.


It is also used for 2 very long jumps(192 units) in ultimate doom. Without strafe50 it is impossible (except with a rl). With strafe50 is hard enough, imo. :P

Read about them here:

E1M9's Jump and

E4M3's Jump.

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Strafe-40 is normal strafing, when you press either strafe key [...] That way you move sideways at 40 units/sec.

Wrong and wrong. Strafe 40 is when you strafe sideways and run forward at the same time. And it does not mean that you walk 40 units/sec - if that was true, it'd take about two minutes to run through E1M1. I'm not sure, but I think 40 refers to the angle between the direction you're facing and the direction you're moving in. Strafe40 is IIRC equal to running straight forward with turbo 125.

Your strafe-50 description is correct, except the turning part: you cannot turn while strafe-50ing. That's what makes it hard to execute.
on the other hand, you do get a 10 unit/sec boost.

His description was correct as he meant the key input, not the result - which, as you point out, is that you can't turn.

But again, the boost is not 10 units/second, it is (I repeat - IIRC) a difference of 10 degrees of direction. Strafe50 is equal to running straight forward with turbo 141.

I know AdamH could clarify the details.

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Fredrik said:

But again, the boost is not 10 units/second, it is (I repeat - IIRC) a difference of 10 degrees of direction. Strafe50 is equal to running straight forward with turbo 141.

In this post I gave what I think are the correct details.

And yes, I am well aware that you can't turn when SR50ing.

Actually, there is some ambiguity in the use of these terms. SR40 and SR50 tend to be the terms used by speedrunners to refer to the combination of running forward and moving to the side (since that is overwhelmingly the most common use). However, when you analyse a demo with LMPC, the SR40/SR50/SL40/SL50 just refers to the sideways movement. The forward or backward movement is shown separately, as GF50/GB50.

BTW, does anyone know exactly what the maximum speed-boost from wall-running is? I recently recorded a demo with what I thought was an SR50-only jump (192 units), but later found it was possible with just SR40 + wall-running.

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Grazza said:

Actually, there is some ambiguity in the use of these terms. SR40 and SR50 tend to be the terms used by speedrunners to refer to the combination of running forward and moving to the side (since that is overwhelmingly the most common use). However, when you analyse a demo with LMPC, the SR40/SR50/SL40/SL50 just refers to the sideways movement. The forward or backward movement is shown separately, as GF50/GB50.

One must remember that the LMPC inputs are not the same as those the game use. SR50 really means SR40 + TRx (don't know the value) + Strafe on. So you can't cheat by inputting SR50 + TRx to LMPC to make the player turn while using Strafe50 or something like that.

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That's not what I was getting at, though I think you can create "illegal" actions by editing LMPC output (or building it from scratch) and then (re-)compiling it. I'm not 100% sure though - on the very rare occasions when I've made a built demo, I've kept them "legal" in that respect.

My point was that when Never_Again referred to strafe-40 and strafe-50 purely in terms of the sideways movement (ignoring any forwards or backwards movement) this wasn't entirely nonsensical. Indeed, the numbers 40 and 50 only really make sense in that context.

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Grazza said:

That's not what I was getting at, though I think you can create "illegal" actions by editing LMPC output.

If it was possible, I'm pretty sure someone would've discovered and exploited it already ;)

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Fredrik said:

If it was possible, I'm pretty sure someone would've discovered and exploited it already ;)

Well, Jonathan Rimmer's bt11-008 demo (E1M1 UV Speed in 8 seconds) starts with the following gametic:

Quote

GF50 SL50 TR46

You'll agree that this would be "illegal" in a standard demo (or any TAS demo, for that matter). [In his text-file, Jonathan stated "I always felt 0:08 on E1M1 was possible with full Strafe50 usage, but a Built demo is the only way to do it", so he was quite open about this - fair enough.] There are several other such gametics in the demo.

In case you're thinking that the game engine will reject this gametic, and process it as if it were GF50 SL40 TR46, I edited the text to make it precisely that, and recompiled. The demo desynched.

I've attached a zip containing the original demo and text, the "source" (.src) from LMPC, the modified source, and the modified (desynching) demo.

EDIT: OK, I think I see what you mean - that, e.g., GF50 SL50 TR46 would be interpreted as GF50 SL40 TR(46-x). I tested that with x=1 and x=5, but it still desynched. If you can supply the value of x that you think is correct, I'll test it.

EDIT2: Actually, your post just confuses me. How do you think the game engine would interpret this tic?

bt11.zip

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Fredrik said:

Wrong and wrong. Strafe 40 is when you strafe sideways and run forward at the same time. And it does not mean that you walk 40 units/sec - if that was true, it'd take about two minutes to run through E1M1. I'm not sure, but I think 40 refers to the angle between the direction you're facing and the direction you're moving in. Strafe40 is IIRC equal to running straight forward with turbo 125.

I get a feeling we're not talking about the same thing here. Strafe40 is just a regular strafe, there's no forward motion involved. The units are obviously not the same used in level design, though what exactly they are beats me =).
My sources are LMPC and the FAQ at Compet-N. What are yours?

His description was correct as he meant the key input, not the result - which, as you point out, is that you can't turn.

That doesn't make sense to me. If you can't turn, why press "turn" and not any other, random key?

But again, the boost is not 10 units/second, it is (I repeat - IIRC) a difference of 10 degrees of direction.

Do you mean "the difference between strafe-40 and strafe-50 is 10 degrees of direction"? AFAIK, there is no difference, it's 45 degrees in both cases.

I know AdamH could clarify the details.

Emailed.

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Fredrik said:

...is quite easy to perform with regular Strafe40.

I believe you meant the E1M4 exit jump.


damnit, remind me to not post, when I am half sleeping. :)
Yeah, i meant e1m4, not e1m9. The e1m9 jump is deadly easy.

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