validate() {

		let valid = true;

		for ( let i = 0; i < this.tracks.length; i ++ ) {

			valid = valid && this.tracks[ i ].validate();

		}

		return valid;

	}
Performs minimal validation on each track in the clip. Returns `true` if all
tracks are valid.

@return {boolean} Whether the clip's keyframes are valid or not.