Emulator

When TASing, you're paused in Dolphin a lot to make precision movements. Unfortunately, Dolphin has an extra frame of latency when using controller inputs because it doesn't seem to apply your input until it's been held for an extra frame. I can demonstrate this when doing frame perfect jumps in Paper Mario: TTYD.

Even though I "hit" the button on the same frame in the TAS input window and on my controller, you can see that I get the landing lag cancel on the second try when I use the TAS input checkbox instead of hitting a button on my controller. If you rewatch the video, you can note that even though I'm hitting a button on my controller, the TAS input window doesn't light up until the next frame I advance when using controller input. Where as I can immediately set them while paused when actually checking the boxes.