A method and an apparatus of image compression, and a memory to store a
data structure for compression. The method includes, for an ordered
series of quantized coefficients of a transform of an image block,
forming from the series events that are a run of non-zero-valued
coefficients in a first contiguous region defined by a breakpoint, a run
of zero-valued coefficients in the first region, or a run of zero-valued
coefficients that ends in a non-zero-amplitude coefficient in a second
region defined by the breakpoint. A codeword is formed for each runlength
of non-zero-valued and zero-valued coefficients in the first region using
a first and a second coding method, respectively, and, and encoding the
runs of zero-valued coefficient that end in a non-zero value in the
second region according to a third coding method, including providing an
exception codeword when the ending amplitude is not 1.