Quantizer with automatic pre-threshold

摘要

An improved video encoder performs quantization after run length conversion. This is in contrast to the conventional encoder wherein quanization takes place before run-level conversion. The inventive encoder design provides a unique look forward process for controlling the number of run-level pairs and thus the number of coded bits. In addition, the stringent speed requirements on the quantizer are reduced because only run-level pairs rather than all DCT coefficients are quantized.