tasvideos.org DOS L1 thread

[Simon]

TASVideos is a community for tool-assisted speedrunning. They have a thread about DOS Lemmings 1 with some action from 2014, but it slept for 4 years.

Now, in December 2018, there is new action:
http://tasvideos.org/forum/viewtopic.php?p=478352#478352

Nobody has concrete plans to TAS L1, but a few prolific TASers are discussing first ideas. I'll happily share information there about the L1 physics. I'm not the most knowledgeable of all Lemmings Forumers, but I hope it's still worth it.

-- Simon

[ccexplore]

I'm most curious to learn about what tooling they have since developed to support TAS on DOS games.  The last time I used DOSBox from a few years ago, there was really no tooling for TAS, not even savestates.  In 2014 I wouldn't think it'd be feasible to TAS anything DOS even if there was interest.

If they have now developed tooling for saved replays (which I'd consider a minimum tooling requirement for TAS) for DOS Lemmings, I'm happy to take a stab at trying to convert some of our (well, probably mostly Clam's) Lemmix replays to whatever file format they are using.

I'd also suggest pointing them to our forum where they can reference our existing threads for challenge solutions and glitches for example.

[ccexplore]

So I read up more on libTAS on TASVideos.org.  Looks like it's a Linux-only tool, so that might limit participation somewhat.

It sounds like the setup is to use libTAS against DOSBox, and run the game inside DOSBox.  Reading some of the caveats made in libTAS's FAQ page, I wonder how usable and reliable this approach is; indeed had anyone even tried it for real for an actual TAS project involving a DOS game?   Maybe someone here who uses Linux regularly can actually try it out can report back.

The movie file format of libTAS is at least documented, although a little lacking in some key details.  Still, given it's basically a record of keyboard and mouse inputs with timestamps, I guess it should be feasible in theory to translate a Lemmix replay file into their format, though it might be a bit of a pain if Lemmix replays don't record mouse cursor positions (I don't recall for sure but I strongly suspect it doesn't).

To be honest, we have a perfectly good* TAS tool for DOS Lemmings already IMHO, and it's called Lemmix. I pretty much steered EricLang's initial development of Lemmix with TAS-like support in mind, even though at the time I didn't even know that kind of thing is called TAS.  The only "problem" is that technically it's not running the actual game, and there are a few well-documented miscellaneous game mechanics differences compared to the actual game.

*or at least proven to be valuable; I'd concede that general usability is somewhat lacking, and it could definitely use a few more advanced features to achieve true parity with mature TAS tools seen in other platforms like consoles

[Simon]

For DOS TASing, there was JPC-RR, a DOS PC emulator for re-recording. This has been around since 2012 or earlier. The 2014 Jazz TAS was made with JPC-RR.

People complain about JPC-RR, it seems very hard to use. In particular, every input is recorded with timestamps, not with frames, and that makes rebasing TASed segments difficult. For example, in Jazz, input had to be sub-frame precise because order during the same frame mattered. Although I wonder how to do it differently with any other solution because DOS machines aren't normed.

I can't tell how easy libTAS is compared to JPC-RR -- I use Linux, but I'm not looking to TAS anytime soon.

I will link to our forum's glitch threads the next time I post in the tasvideos L1 thread!

-- Simon