A rate control method for motion JPEG 2000

In Motion JPEG2000 each frame of a video is encoded with JPEG2000. In JPEG2000, the post-coding rate distortion optimisation (PCRD-opt) technique is recommended for rate control. The advantage of using PCRD-opt for rate control is that at any given rate the optimum visual quality can be achieved for that rate. However, implied in the optimisation procedure each code-block is over-coded. Since the encoding process in JPEG2000 is one of the slower operations, too much over-coding is undesirable especially in video applications. Over-coding also results in more memory than necessary for buffering the intermediate compressed data. This paper proposes a technique that minimises the amount of over-coding in the arithmetic encoding step while maintaining image quality. This is achieved by terminating the encoding process of a code-block once terminating conditions have been met. The terminating conditions are a set of rules based on the coding of the current code-block and other heuristics. The terminating conditions will be discussed fully in detail in this paper. Visually the image quality using the proposed rate control scheme is comparable to that of using PCRD-opt. Furthermore, the proposed rate control strategy produces a fully compliant JPEG2000 codestream.