Start:

When hotbar pops up in tutorial & yellow key/When in game clock changes time {7:51; 8:51} in all other levels (PC)

When black bars fully fade/When starting letter fully fades (Console & Mobile) {Use the one that occurs LAST}

End:

When black bars BEGIN to close/When yellow key is obtained (PC)

When the player stops moving/When the screen turns black in the tutorial (Console & Mobile)

Additional Notes:

Which you use depends on the level and platform you are on

Retimings will be done using https:/​/​github.​com/​Slush0Puppy/​retime

It is recommended that runs be uploaded to YouTube to be retimed using "SP's Retiming Tool" otherwise a frame-by-frame method will be used for videos on other platforms

For PC there always will be a 100-200 ms difference in timing due to hardware/loading time differences (starting on first input won't help since most levels are time-based)