Timing OoT

Full runs of The Legend of Zelda: Ocarina of Time are timed using a real clock. As the PAL N64 version of Ocarina runs at 5/6 the speed of NTSC and GameCube versions, PAL is at a massive disadvantage on full speedrun, unless you scale your time to match.

Start and end points

It is not entirely obvious when one should start and finish timing. Here are your options:

Start points

• Obviously the first point one could BEGIN timing at is the instant that the N64 is switched on. However, at this point, gameplay itself has not begun. It still remains to create a file and sit through the intro.
• You could begin timing at the instant that the player presses Start after beginning a new game file. If a file is set up beforehand and the player just mashes A to get through the initial intro and menus, this can be about 11 or 12 seconds later. However, gameplay proper still doesn't begin yet, because there are 3 minutes and 34 seconds of introductory dialogue to page through as well.
• Lastly, you can begin timing at the instant control is turned over to the player: the point when Link's house is first shown from above.

End points

• Most people stop timing at the end of gameplay proper: this is the moment that control is lost when Link delivers the final blow to Ganon's head.
• Dialogue, that is, player interaction, ceases when Zelda says "The way you are supposed to be", 3 minutes and 31 seconds later.
• To be extra-thorough, the game itself finishes when the music stops another 7 minutes and 42 seconds after THAT. (I'll ignore the repetitions of the Scarecrow Song which play if you leave the game long enough.)

All in all that yields nine ways to time the game, more than half of which are utterly stupid.

When to time between?

Speed Demos Archive

Speed Demos Archive begins timing when Link jumps out of bed and stops timing when the final blow is delivered to Ganon.

Twin Galaxies

Twin Galaxies begins timing when Start is pressed on a new file, and stops timing when the final blow is delivered to Ganon. It's unknown why the initial dialogue is included in the time, but the trailing dialogue is not.

Tool-Assisted Speedrun

The current 2:33:25 TAS of OoT begins timing the instant the console (emulator in this case) is turned on and stops timing after the final dialogue is completed. A time of 2 hours 29.8 minutes is given for the final blow on Ganon.