Thomson Licensing

Lila Huguenel

Edouard Francois

Dominique Thoreau

Philippe Guillotel

Olivier Le Meur

Edouard François

The method comprises a coding of a source block according to a coding mode wherein the selection of the coding mode is carried out, for a source block, according to coding error estimations and source block coding cost estimations for the different coding modes tested, the coding error being estimated, for a coding mode, according to the sum of the absolute values of coefficients obtained after a mathematical transformation in the frequency domain of the residue block related to this coding mode and as a function of the sum of absolute values of quantized coefficients corresponding to this coding mode. An application is the decision of the coding mode for data using the MPEG 2 or MPEG4-AVC standard.

Method and device for coding a video image with a coding error estimation algorithm

The invention relates to a method of locally adjusting a quantization step for each region of an image with respect to a setpoint quantization step. The method comprises the steps of:

Method for locally adjusting a quantization step and coding device implementing said method

The invention relates to a method of locally adjusting a quantization step for each region of an image in a sequence of n images. The method comprises the following steps; calculating, for each image of the sequence, a first difference of bits saved on the potential masking region when quantizing it with a first quantization step and a second difference of bits required by the region of interest when quantizing it with a second quantization step; and in each image of the sequence, assigning to the potential masking region the first quantization step and if the sum of the n first differences of bits is higher than the sum of the n second differences of bits assigning said second quantization step to said region of interest and otherwise assigning a third quantization step such that the sum of said n first differences of bits is distributed between the regions of interest according to a reconstruction quality criterion.

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Rennes, France

Lila Huguenel