Patent ID: 6891889

Claim:
A method of determining a quantization parameter for video compression, the method comprising: quantizing a block characteristic for blocks in a video frame, producing a quantized block characteristic; using the quantized block characteristic to obtain a candidate quantization parameter; using the quantized block characteristic as an index to a look-up table of possible quantization parameter values, wherein producing the look-up table comprises defining a joint probability density function of a quantization parameter and a picture type, applying vector quantization to convert the joint probability density function to a set of code vectors, quantizing the block characteristic, and producing a look-up table with the quantized block characteristic as a table index and the code vectors as the values; summing a number of bits for the blocks in the video frame producing a candidate bit rate, wherein the quantized block characteristic and the candidate quantization parameter determine the number of bits per block; and setting the candidate quantization parameter as the quantization parameter for the frame, if the candidate bit rate is greater than a predetermined bit threshold.