I'm a TASer. TAS is not a user! The abbreviation for S is "SUPERPLAY", not "SPEEDRUN".
TAS = NOT PERFECT gameplay.

TAS(Tool-Assisted Speedrun also Tool-Assisted Superplay). It program uses "Emulators" to clear games quickly. It's a video that shows good results by playing it over and over again.

Depending on good the tools are he could slow down or go frame by frame and record an input. When something doesn't go his way he can reload into a previous state as many times as he needs to get the results he wants. Which can take many many redos.

I don't just play Tekken, but I play a lot of other games. also doing the Street Fighter, Virtua Fighter series. please don't ask for Tekken 6, Tekken TAG 2. Go to "tasvideos.org" and make a request. I'm not a game developer!!!