Video rate control

A method comprising:

• determining multiple less probable symbol (LPS) reduction ratios across a range of multiple threshold band half-widths, each respective LPS reduction ratio of the multiple LPS reduction ratios corresponding to a respective threshold band half-width of the multiple threshold band half-widths;
• determining a targeted bit-count for a current bit plane;
• calculating a desired bit-count reduction ratio using the targeted bit-count for the current bit plane and a complexity of the current bit plane;
• ascertaining a desired LPS reduction ratio based on the desired bit-count reduction ratio and responsive to a model parameter;
• and
• selecting a minimal respective threshold band half-width from among the multiple threshold band half-widths such that the corresponding respective LPS reduction ratio of the multiple LPS reduction ratios is not smaller than the desired LPS reduction ratio.

A device comprising:

• one or more processors;
• and
• one or more processor-accessible storage media storing processor-executable instructions implemented by the one or more processors for carrying out acts comprising:
• initializing a model parameter, a buffer size, and a buffer fill level, wherein the model parameter comprises a ratio of a less probable symbol (LPS) reduction ratio and a bit-count reduction ratio;
• calculating a complexity of a bit plane of an image;
• calculating a plurality of less probable symbol (LPS) reduction ratios across a range of threshold band half-widths so that each LPS reduction ratio corresponds to one of a plurality of threshold band half-widths within the range;
• calculating a targeted bit-count based on a target frame rate and the buffer size;
• and
• selecting a threshold band half-width from the plurality of threshold band half-widths, each respective threshold band half-width of the plurality of threshold band half-widths corresponding to one of the respective LPS reduction ratios of the plurality of LPS reduction ratios, wherein the selecting is responsive to a desired LPS reduction ratio that reflects a desired bit-count reduction ratio, wherein the desired LPS reduction ratio, further reflects the specified model parameter, wherein the desired bit-count reduction ratio is derived from the calculated targeted bit-count, wherein in the selecting the threshold band half-width further comprises:
• calculating the desired bit-count reduction ratio using the targeted bit-count and the complexity of the bit plane;
• ascertaining the desired LPS reduction ratio based on the desired bit-count reduction ratio and the specified model parameter;
• selecting a minimal respective threshold band half-width, from among the plurality of threshold band half-widths, that corresponds to a respective LPS reduction ratio, from among the plurality of LPS reduction ratios calculated, that is not smaller than the desired LPS reduction ratio;
• providing the selected minimal respective threshold band half-width for use in encoding the bit plane;
• encoding the bit plane based on the selected minimal threshold band half-width to produce an encoded bit plane;
• calculating an actual bit count reduction ratio from the encoded bit plane;
• calculating an interim updated model parameter based on the actual bit count reduction ratio calculated from the encoded bit plane;
• smoothing the calculated interim updated model parameter to produce an updated model parameter;
• and
• providing the updated model parameter for processing a next bit plane.

One or more processor-accessible storage media comprising processor-executable instructions that, when executed, direct a device to perform actions comprising:

• determining an entropy-based complexity of a bit plane of an image;
• determining a targeted bit-count for the bit plane of the image;
• selecting a threshold band half-width based on a desired bit-count reduction ratio and a model parameter, by:
• calculating the desired bit-count reduction ratio using the targeted bit-count and the complexity of the bit plane;
• ascertaining a desired LPS reduction ratio based on the desired bit-count reduction ratio and the model parameter;
• selecting a minimal respective threshold band half-width, from among a plurality of threshold band half-widths, that corresponds to a respective LPS reduction ratio, from among a plurality of LPS reduction ratios calculated, that is not smaller than the desired LPS reduction ratio;
• encoding the bit plane based on the selected minimal threshold band half-width to produce an encoded bit plane;
• calculating an updated model parameter based on the encoded bit plane;
• and
• providing the updated model parameter for processing a next bit plane.