Editing Tool-assisted speedrun (section)

===Re-recording emulators===
Tool-assisted speedrunning relies on the same series of inputs being played back at different times always giving the same results. The emulation must be [[deterministic]] with regard to the saved inputs, and [[random seed]]s must not change. Otherwise, a speedrun that was optimal on one playback might not even complete it on a second playback. This desynchronization occurs when the state of the emulated machine at a particular time index no longer corresponds with that which existed at the same point in the movie's production. Desyncs can also be caused by incomplete savestates, which cause the emulated machine to be restored in a state different from that which existed when it was saved. Desyncs can also occur when a user attempts to match inputs from an input file downloaded from TASVideos and fail to match the correct enemy reactions due to bad AI or RNG.