1. An apparatus, comprising: a block processing pipeline configured to process blocks of pixels from a video frame; and a memory; wherein the block processing pipeline comprises a context-adaptive coding component; wherein the memory stores a plurality of context model states, each associated with one of a plurality of contexts; wherein the context-adaptive coding component comprises a cache configured to store context model states associated with one or more of the plurality of contexts; wherein, for each of a plurality of syntax elements, the context-adaptive coding component is configured to: determine a context for the syntax element; obtain a context model state for the context from the memory or from the cache; and code the syntax element, dependent on the obtained context model state; and wherein the context-adaptive coding component is further configured to: store a context model state in the cache, modify a context model state in the cache, or modify an interface of the cache dependent on having coded one or more of the syntax elements.