We need a tempo parameter, which could be different from a part of the piece to another (precise tempo change, accelerando...). We will take tempo values between 0 and 256, which will correspond to the number of beats pro minute.
Note position and note duration are also needed for start time errors, duration errors and lack of regularity errors. Duration will be the "relative" duration of the note, i.e. the note value (1, 1/2, 1/4, etc...) linked to the current tempo.