JPEG packed block data structure for enhanced image processing

Abstract

An intermediate data format which is readily convertible to or from JPEG compliant data streams and to or from image data provides, in most circumstances, accelerated encoding and decoding in a degree sufficient to allow additional processing without necessitating increase of processor power even in relatively time-critical applications such as high-speed printers and image browsers. The format features flags which indicate if S>8 (indicating that extra bits are required to uniquely encode an orthogonal transform coefficient value) or runs of zero-valued orthogonal transform coefficients longer than sixteen are present in a block of data. The block of data can be tested for these conditions and flags set once per block or once per image. Extensive processing can thus be omitted if either or both of these conditions are not present, as will generally be the case.

1 - 6 . (canceled)  
     
     
         7 . A data format for a block of encoded data including 
 a first pair of bytes representing to a decoder a block number, a Klast value and at least one flag indicating if all said coefficient values in said block are coded in eight bits or fewer or if any requires more than eight bits to be uniquely coded,    a second pair of bytes respectively representing to said decoder an R/S value and a coefficient value.    
     
     
         8 . A data format as recited in  claim 7 , further including 
 at least one additional pair of bytes including a EOB byte and a padding byte.    
     
     
         9 . A data format as recited in  claim 7 , wherein said first pair of bytes further includes 
 another flag indicating if any runs of consecutive zero-valued coefficients greater than sixteen are present in said block.    
     
     
         10 . A data format as recited in  claim 7 , wherein said Klast value provides an index of a last non-zero coefficient value in a block.