A host decoder and accelerator communicate across an acceleration interface. The host decoder receives at least part of a bitstream for video, and it manages certain decoding operations of the accelerator across the acceleration interface. The accelerator receives data from the host decoder across the acceleration interface, then performs decoding operations. For a given frame, settings based on an uncompressed frame header can be transferred in a different buffer of the acceleration interface than a compressed frame header and compressed frame data. Among other features, the host decoder can assign settings used by the accelerator that override values of bitstream syntax elements, can assign surface index values used by the accelerator to update reference frame buffers, and can handle skipped frames without invoking the accelerator. Among other features, the accelerator can use surface index values to update reference frame buffers, and can handle changes in spatial resolution at non-key frames.