Demo playing

Okay, I have a real demo problem here. I can't use the original DOOM executable since it's pure DOS and doesn't work well under XP, I can't use Doom95 because any demo I play always goes horribly out of sync, and for some strange reason I can't play them with zDoom because "v1.9 demos are no longer supported". If they aren't, then what is? And why?

Prboom is compatible with the original DOOM/DOOM2 demo's in 99.999% of cases. I use it in XP and it works great. Also has an opengl version.

the 0.001% of demos it wont play are the weird bugs from the original DOOM code. It's not something I've encountered.

99.999%? I haven't encountered a single 1.9 demo that won't play back in PrBoom.

The only problems I was having with doom2 running on XP, is the music was sounding shitty, but after a quick driver upgrade, things have improved.

Fredrik said:

99.999%? I haven't encountered a single 1.9 demo that won't play back in PrBoom.

PrBoom is great for playing 1.9 demos (I use it all the time), but the compatibility isn't quite that perfect:
* STRAIN demos will virtually always desync when there are holobots on the level (since PrBoom doesn't handle them correctly)
* Ledmeister's Blacktwr demo (blackbug.lmp) desyncs
* Vile's HR2 map32 max demo only has a chance of playing back with Doom2.exe - no chance with PrBoom
* Vile's E4M1 NM demo (n4m1-035) desyncs - a telefrag doesn't quite work right
[edit]* Hacx demos will virtually always desync when there are Terminatrixes on the level (since PrBoom doesn't handle them correctly) - there are some other problems too[/edit]

I'm sure I've come across others (incl. one or two recent compet-n demos), but that is enough to refute any claim that more than 99.999% of 1.9 demos play back OK in PrBoom.

Still, the answer to the original question is that PrBoom is definitely the best solution. Or try running Doom2.exe from a DOS prompt and with -nosound.

Allright, I'll try that. Though it's nice to have one thing that is OK for everything; why does zDoom not play them?

ZDoom cant play Doom demos cos its really playing the Doom levels in Hexen format, cos Hexen was like the last "Doom" format exe so it had a lot of extra fx and stuff for editers to use in Doom (i.e. all the new type stuff the Hexen ppl/map makers could play with)...

and i cant remember but their are a few more old compet-n demos for Final Doom and some wouldnt work.. but yeah i had Xp ;) and the -nosound thing should work, i setup the .cfg to use no sound card and it played the game just fine, just no sound or music :\

hope/glad we helpped you out :)

Sokko said:

why does zDoom not play them?

In general, demos will only play back with the same program (and same version) with which they were recorded. (And in the case of many versions of Zdoom, they don't necessarily play back then!). There is a fair degree of compatibility between the various versions of Legacy, and some compatibility between Boom, vanilla, MBF and the various TAS programs, but you never know whether they will work until you've tried.

AFAIK, the incompatibilities are due to differences in the game physics and the random number generation (a lot of things in Doom are determined by "random" numbers - if they are not generated in the exact same way, a demo will desync). I'm not expert on this, BTW; other people will doubtless be able to provide more accurate info.

The demo compatibility of PrBoom was only achieved thanks to a great deal of effort by the PrBoom team.

The text file that accompanies a demo normally indicates which program was used to record it. It will often also indicate if it will play back correctly with other programs. Compatibility between 1.9 and PrBoom is so good though that you can generally assume it will play back OK, unless it is specifically mentioned otherwise.

BTW, I have been recording with PrBoom's 1.9 compatibility mode recently. The only demo of mine that desyncs in 1.9 is my NM Pacifist/Speed on Nuts.wad. It goes totally haywire well before it crashes with a memory error; the UV Pacifist/Speed demo is fine up until it crashes with a memory error :)

Sweet Prince said:

and i cant remember but their are a few more old compet-n demos for Final Doom and some wouldnt work.

You need to be careful with Final Doom demos. Some were recorded with the Final Doom exes, and others with doom2.exe (and -file plutonia.wad or -file tnt.wad). It should always say in the textfile.

If they were recorded with the Final Doom exes, then you need to play them back as follows:
prboom -iwad plutonia.wad -playdemo demoname
prboom -iwad tnt.wad -playdemo demoname

If they were recorded with Doom2.exe, then you need to play them back as follows:
prboom -iwad doom2.wad -file plutonia.wad -playdemo demoname
prboom -iwad doom2.wad -file tnt.wad -playdemo demoname

In XP you may need to give the full file paths. Oh yeah, and for demos on TNT.wad map31, you will need to download the bugfix.

Hope this helps.

Grazza said:

I'm sure I've come across others (incl. one or two recent compet-n demos), but that is enough to refute any claim that more than 99.999% of 1.9 demos play back OK in PrBoom.

From the last Compet-N demo pack (03/19/03), all of the following demos go out of sync under PRBoom:

AF04-437.LMP
af04-547.lmp
av32-441.lmp
e1nm0646.lmp
lv17-159.lmp
lv17-201.lmp
pp08-239.lmp

And yes, I was using Doom v1.9 and the vanilla Doom compatibility option on.
So from what I am experiencing, PRBoom can play MOST of the demos (99.999%?) but not ALL.

Still, the answer to the original question is that PrBoom is definitely the best solution. Or try running Doom2.exe from a DOS prompt and with -nosound.

Argh!

Cacodreams said:

From the last Compet-N demo pack (03/19/03), all of the following demos go out of sync under PRBoom:

All the ones you list play back fine for me. I'm using GLBoom, but that certainly shouldn't make any difference.

Sounds like something is fundamentally wrong... Did all the other demos in the update play back OK for you?

Are you using the right version of PrBoom (2.2.3)?

I should emphasize that when I said about "one or two" other compet-n demos that desync, I watch all compet-n demos, and the number where there were problems in recent months was literally one or two. And it's quite possible (I don't remember) that they were tnt.wad demos recorded with Doom2, where I forgot about the advice I gave above! EDIT: I've remembered one of them, and in that case at least wasn't just me being stupid: Ryback's HR18-348.LMP desyncs in PrBoom.

BTW, you don't need to specify the compatibility level when playing back demos - the program automatically detects it.

Addendum to a post above, regarding ther NutsNP52.lmp demo that I referred to: to see the weird desync (which occurs at the point you enter the second room), you need to free up a large amount of resources for Doom2.exe - otherwise the memory crash intervenes first.

The demo I'm talking about also does not work with PrBoom. It's a NM Speed demo of the whole game, filename 30nm3143 I believe. It screws up on the second level, <speech slows as realization sinks in> right... near... the... shotgun... seargent...

...which is where that weird bug is where the LOS or something is calculated incorrectly! Either the demo was recorded on a fixed version and PrBoom doesn't fix this, or it was recorded on a unfixed version and PrBoom does fix this. Either way would cause a bug. The exact point where it messes up goes by way too fast to see, but it's somewhere right near that cell. The player starts making a few freaky movements that don't make sense, then something kills him, which obviously shouldn't happen. He then starts the level again when he wasn't supposed to, causing him to run around randomly and shoot the walls. He probably just stays there forever, because in his random shooting he actually manages to pick off the guys on the ledge. So, what _AM_ I going to do?

P.S. Is there a program that will lump a bunch of demos into one big demo? If not, when will we ever get a source port that has you select demos from a list of files, rather than running it from the command line every time?

Sokko said:

P.S. Is there a program that will lump a bunch of demos into one big demo? If not, when will we ever get a source port that has you select demos from a list of files, rather than running it from the command line every time?

They used such a program for Doom done quick... But I can't remember it's name...

Grazza said:

You need to be careful with Final Doom demos.
....
Hope this helps.

thanks! yeah it had a lil table telling if a demo from the pack would play under DOS or Doom95... also they said they used the Doom2.exe not fdoom and using the -file... cos they wanted the 31 always run thing... i just set no sound card or music card in the cfg and played it with the DOS exe... i always forget about the -nosound but now i have Win98SE and i dont need the -nosound anymore but i always rembember it now lol