Although the length of this movie is 21:50.6 when timed with our standard method, applying the timing method used by most Zelda speedrunners (until last hit on Ganon) would result in a final time of 18:46.85. It's important to note this so that there's no confusion about which runs are faster than the others.
In this TAS of The Legend of Zelda: Ocarina of Time, the author aims to beat the game as quickly as possible. He achieves this by exploiting a large sequence break which involves "tricking" the game into warping Link directly from the Deku Tree (the first dungeon) to Ganon's Castle. Child Link then goes on conquering the whole Castle without a single thought about becoming an Adult beforehand.
Despite how quickly this game can be beaten these days, this run is almost one minute faster than its predecessor thanks to a new trick at the Tower Collapse Sequence and many small improvements throughout the run.
This TAS was done using the Japanese version of the game. The reason for this is that the text is significantly faster than in the English version, which means that far less time is spent waiting for text boxes and cut scenes to end before getting back to the action.
The author's notes explain in great detail many of the things done in this TAS, which may be confusing to those who aren't familiar with Ocarina of Time speedrunning. Reading them is strongly advised.
Note: There are encodes of higher resolutions in the discussion thread.