In some embodiments, a method determines a combination of sub-bitstream chunks from a plurality of sub-bitstreams for a video. The combination of sub-bitstream chunks includes a quality measurement. The method exchanges a sub-bitstream chunk in the combination of sub-bitstream chunks with another sub-bitstream chunk from another sub-bitstream in the plurality of sub-bitstreams based on a relationship of a change in bitrate to a change in quality due to the exchanging. The method continues to exchange a sub-bitstream chunk in the combination of sub-bitstream chunks with another sub-bitstream chunk until the quality measurement of the combination of sub-bitstream chunks meets a target quality and outputs the combination of sub-bitstream chunks.