Image Number 11 for United States Patent #8121427.
A method, and apparatus, and logic encoded in one or more computer-readable tangible medium to carry out a method of determining a breakpoint position in an ordered sequence of quantized transform coefficients of a block of image data for a hybrid variable length coding the ordered sequence. The breakpoint location in the sequence is between a low-frequency region and a high-frequency region. The hybrid variable length coding method includes coding the low-frequency region using a selected low-frequency variable length coding method; coding the high-frequency region using a selected high-frequency variable length coding method; and coding the position in the sequence of the breakpoint. The breakpoint location is determining uses a relatively simple and fast method based on pre-defined cost criteria. A method is included that instead of coding the breakpoint separately, codes the breakpoint jointly with coefficient events.