1. A method of coding video data, the method comprising: determining a first target reference index representing a first reference picture to which a candidate motion vector predictor for a current motion vector refers; coding at least one of a slice header or a picture parameter set (PPS) including data representing a predetermined value for an additional target reference index representing a second reference picture different than the first reference picture; determining that the first reference picture comprises a long-term reference picture; and in response to determining that the first reference picture comprises the long-term reference picture, coding, during temporal motion vector prediction (TMVP) of the current motion vector using the candidate motion vector predictor, the current motion vector such that a reference index for the current motion vector has the predetermined value of the additional target reference index instead of the first target reference index of the candidate motion vector predictor.