A method of encoding video data, the method comprising: obtaining a plurality of intra-prediction modes available for coding a current block of video data; computing an approximate cost for each intra-prediction mode identified in a current set of intra-prediction modes of the plurality of intra-prediction modes that includes a pre-defined set of intra-prediction modes having at least one intra-prediction mode, wherein the current set of intra-prediction modes includes fewer intra-prediction modes than the plurality of intra-prediction modes available for coding the current block of the video data; computing an approximate cost for one or more most probable intra-prediction modes for the current block determined based on intra-prediction modes used to encode one or more neighboring blocks of video data adjacent to the current block; comparing each of the approximate costs computed for the one or more most probable intra-prediction modes to a threshold; replacing one or more of the intra-prediction modes identified in the current set of intra-prediction modes with the one or more most probable intra-prediction modes if the comparison satisfies the threshold; performing a rate distortion analysis with respect to each intra-prediction mode identified in the current set of intra-prediction modes to determine a rate distortion cost for each intra-prediction mode identified in the current set of intra-prediction modes after said replacing one or more of the intra-prediction modes identified in the current set of intra-prediction modes with the one or more most probable intra-prediction modes based on the comparisons; and performing intra-prediction coding with respect to the current block in accordance with one of the intra-prediction modes identified in the current set of intra-prediction modes based on the determined rate distortion costs to encode the current block. obtaining a plurality of intra-prediction modes available for coding a current block of video data; computing an approximate cost for each intra-prediction mode identified in a current set of intra-prediction modes of the plurality of intra-prediction modes that includes a pre-defined set of intra-prediction modes having at least one intra-prediction mode, wherein the current set of intra-prediction modes includes fewer intra-prediction modes than the plurality of intra-prediction modes available for coding the current block of the video data; computing an approximate cost for one or more most probable intra-prediction modes for the current block determined based on intra-prediction modes used to encode one or more neighboring blocks of video data adjacent to the current block; comparing each of the approximate costs computed for the one or more most probable intra-prediction modes to a threshold; replacing one or more of the intra-prediction modes identified in the current set of intra-prediction modes with the one or more most probable intra-prediction modes if the comparison satisfies the threshold; performing a rate distortion analysis with respect to each intra-prediction mode identified in the current set of intra-prediction modes to determine a rate distortion cost for each intra-prediction mode identified in the current set of intra-prediction modes after said replacing one or more of the intra-prediction modes identified in the current set of intra-prediction modes with the one or more most probable intra-prediction modes based on the comparisons; and performing intra-prediction coding with respect to the current block in accordance with one of the intra-prediction modes identified in the current set of intra-prediction modes based on the determined rate distortion costs to encode the current block.