US Patent 7457461 Video compression noise immunity

A method of improving run length video encoding commands is described in which all compression commands that require a current pixel value to be compared to a previously sent pixel value to determine whether compression can take place in a longer run is adjusted to relieve stringent match conditions. Instead of requiring an exact match, the compression engine subtracts one pixel value from another, and compares the absolute value of the result to a threshold value. In this way, run lengths can be lengthened for purposes of compression and compression efficiency can be increased.