Patent ID: 8452113

Claim:
Method of encoding an image divided into non-overlapping macroblocks themselves divided into non-overlapping blocks of N by N pixels into a binary stream comprising the steps of: transforming each of said block into a transformed block of coefficients comprising one low frequency coefficient and N 2 -1 coefficients, called high frequency coefficients, of higher frequencies than said low frequency; quantizing each coefficient of each of said transformed blocks with a quantizing parameter; encoding said quantized coefficients into a binary stream; wherein the low frequency coefficients of said transformed blocks are quantized with a same first quantizing parameter and the high frequency coefficients of a same macroblock are quantized with a same second quantizing parameter wherein said second quantizing parameter is computed as the sum of said first quantizing parameter and of an increment, wherein said increment depends on whether the macroblock belongs to a skin region, to a flat region and further depends on a level of average luminance of said macroblock.