A component of an entropy encoding stage of a block processing pipeline (e.g., a CABAC encoder) may, for a block of pixels in a video frame, accumulate counts indicating the number of times each of two possible symbols is used in encoding a syntax element bin. An empirical probability for each symbol, an estimated entropy, and an estimated rate cost for encoding the bin may be computed, dependent on the symbol counts. A pipeline stage that precedes the entropy encoding stage may, upon receiving another block of pixels for the video frame, calculate and use the estimated rate cost when making encoding decisions for the other block of pixels based on a cost function that includes a rate cost term. The symbol counts or empirical probabilities may be passed to the earlier pipeline stage or written to a shared memory, from which components of the earlier stage may obtain them.