In a video coding system, an encoder may include a coding engine to predictively code input video, a decoder to reconstruct reference pictures generated by the coding engine, a reference picture cache to store the reconstructed reference pictures, a patch cache to store prediction patches generated from other sources, and a prediction search unit to search among the reference picture cache and the patch cache to generate prediction references for use by the coding engine while coding input video. The prediction patches may be assembled from a variety of sources including: predefined image content, reference pictures being evicted from the reference picture cache, image content of prior coding sessions and image data stored by applications on a common terminal where the encoder resides. A decoder may store prediction patches in its own patch cache for synchronous decoding.