"you can't do both of them in the same frame"
if it's impossible by human limitations, I think it's OK to use it. If it's possible to recreate it real-time (with tools), than it's should use that way, otherwise the TASer exploits the nature of LMP. BTW from the doom wiki, I've thought it's possible in real time but hard to pull it off.
"It's trivial to hex-edit such LMPs, but is it possible to actually produce valid inputs within a game that lead to that result? In this case the answer's yes, it's been shown that it's possible."
Where? And... how can you proof that you are able to press an input on the very first frame without tampering with the LMP? Only "easy" thing comes in my mind is simply modifying the source code to warn the user about the first G_BuildTiccmd (ticcmd_t cmd) with the tic number.
edit: "This is easily detectable with basic tools" - I wonder how a judge would find 1 tic of 51 or whatever arbitrary strafe value in the midst of framecount*
140 4 bytes + header, but I guess they used some sort of utility to filter this out, right? not just blindly accepting user input without sanitizing first and just thinking "wow it runs in dosbox this is totally legit"
edit2: I've exported the 3 demos from doom.wad. Beginning of the demo files:
Demo1: 6*WT, GB4, 3*WT, GF50....
Demo2: GF15, 6*WT, GF11, 3*WT, GF1, WT...
Demo3: GF50, 5*WT, GF9, 4*WT, GF25....
Well, doesn't proves anything so far, I was expecting all of them starting with 6 WTs.
edit3: Tried to look up for SR50 technical background from doomworld. The
only post (Doom2 thread where probably Akse and Aqfaq discuss) I found about SR50 gives some verification to the above exported (doom1) Demo inputs: "for example you can only turn in the first tic of the next map, then on the 5th-8th tic but I don't know for sure about this"
Well, I'm kinda disappointed that a game released in 1993 and probably also the root of all TASes doesn't have all the techical informations or proofs what's possible, also considering that we have the source...