An example video encoder is configured to receive an indication of merge mode coding of a block within a parallel motion estimation region (PMER), generate a merge mode candidate list comprising one or more spatial neighbor motion vector (MV) candidates and one or more temporal motion vector prediction (TMVP) candidates, wherein motion information of at least one of the spatial neighbor MV candidates is known to be unavailable during coding of the block at an encoder, determine an index value identifying, within the merge mode candidate list, one of the TMVP candidates or the spatial neighbor MV candidates for which motion information is available during coding of the particular block, and merge mode code the block using the identified MV candidate.