What is a demo?

[[ITA]DDOOMER46]

sorry if this question might seem a bit silly, but what is a demo? I want to know the simple terms, I don't want an explanation taken from the doom wiki or something

[Quill]

Basically, a demo is a recording of your game session. Except instead of recording a video, it records the exact inputs of the player.

Edited January 5, 2023 by Quill

[Sneezy McGlassFace]

https://doomwiki.org/wiki/Demo

 

edit: sorry, your message is very strangely formatted and didn't show up whole.

Demo is a list of recorded actions of the player and all the monsters behaviour, and everything that happened in the game. There's more to it but this is the tl;dr

Edited January 5, 2023 by Sneezy McGlassFace

[thelamp]

Let me try this analogy, maybe it will help you.

 

Recording video is akin to a record, the grooves in a record are what "store" the music. A record player must be used to playback the record, and it will sound the way it was when it was recorded. Same as video, some program (probably VLC) must be used to play it, and it will appear as it was recorded.

 

A demo, on the other hand, is more like a drum (or other device) made for a player piano. Key difference here, is that an actual instrument is being used for playback, not just a program/device (the record player/VLC). In the same way that a player piano "plays itself", a demo is the game "playing itself" it is not recorded music/video. The playback will be affected by the device you use to play it back, and so it must be setup correctly in order to playback correctly.

 

in short:

a video/record is a recording of the thing itself

whereas a demo/player piano is a series of instructions that tell the game/piano how to play the thing

Edited January 5, 2023 by thelamp

[Shepardus]

It's a replay, like what you see in the background of the main menu (unless you're using a source port that doesn't play back vanilla demos, e.g. ZDoom).

[DoomGater]

An LMP is a MIDI-File

when a Video is an MP3   :-)

 

Confused? OK. LMP- and MIDI-files are just a bunch of commands gathered together in a file to tell the engine what to exactly do.

"Turn right, make 10 steps an fire" could be the clear text translation of an LMP. "Select a bass sound and play an E2 note with medium velocity"

could be the clear text translation of a MIDI File.

BOTH are useless without some interpreter/engine/MIDI Device.

 

MP3 and Videofile are just containers holding the visible/audible mediastream representing the result of playing back the aforementined files.

MIDI Files and LMPs save space, are convenient and can easily be edited and sent.

 

Edited January 7, 2023 by DoomGater

[No-Man Baugh]

You know that "attract mode" in arcade games and old console games that plays the game for a short bit while the title screen sits idle?

 

 

Well Doom has that too! And it lets you make your own attract mode file (which are know in the community as "demos") by punching in the -record parrameter and also lets you play back demos like you would with a wad file with the -playdemo parrameter

 

The relative ease of recording playing and sharing demos in comparison to digital video at the time of Doom's hayday made demos the go-to for Doom's speedrunning community (which probably makes it the most well-preserved early speedrun communities afaik)

[xX_Lol6_Xx]

On 1/5/2023 at 11:10 AM, [ITA]DDOOMER46 said:

I don't want an explanation taken from the doom wiki or something

I mean, the explanation of the DoomWiki is not that complicated.

Quote

A demo lump is a sequence of instructions which tells the game engine what actions the player will perform: when he will take a step forward, turn around, shoot, switch weapons, etc. It is interpreted by the engine as keyboard and mouse input, thereby allowing anyone to watch a recreation of the original recorded actions.

 

If no game or demo is begun immediately when launching vanilla Doom (either from the in-game menus or by using command line arguments), three built-in demos soon begin to play repeatedly, evoking an arcade game's attract mode.

Sources: https://doomwiki.org/wiki/Demo#Technical_information

https://doomwiki.org/wiki/Demo#Built-in_demos

But if you want something even simpler, it's the recording of your inputs, that the engine can play back to replicate your game session.

[TheMagicMushroomMan]

A demo is a demonstration of a democrat demolishing demons for the sake of demoralizing and demobilizing the democracy of the demons. It's a little bit like porn - you aren't in on the action, but you can learn a lot by watching.

[Devalaous]

What is a demo? A miserable little pile of inputs!

[roadworx]

i don't mean to make you feel bad or anything op, but how can you possibly manage to mess up your formatting that badly