EFFICIENT VIDEO BLOCK MODE CHANGES IN SECOND PASS VIDEO CODING

This disclosure describes techniques for second pass video coding in a multi-pass video coding scenario. The coding modes for some video blocks encoded during a second pass may be changed relative to the coding modes used for such video blocks in the first pass. However, motion information does not change for those video blocks that have the changed modes. In particular, mode changes can be made in the second coding pass relative to the modes used in the first coding pass without changing the manner in which motion information will be derived at the decoder, e.g., due to similarities between the original modes of the first pass and changed modes used in the second pass. The second pass coding techniques may also include quantization parameter adjustments, and the mode changes can cause such quantization parameter adjustments to have more profound refinements effects on the second pass coding.