Abstract: 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.

Abstract: 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.

Abstract: 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: assigning, to said region of interest, a first quantization step, lower than or equal to said setpoint quantization step; determining a second quantization step higher than or equal to said setpoint quantization step and lower than or equal to a third quantization step such that the number of bits required by the region of interest is lower than the number of bits saved on the potential masking region; and assigning, when such a second quantization step exists, said second quantization step to said potential masking region, otherwise assigning said third quantization step to said potential masking region.

Abstract: 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.

Abstract: 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: assigning, to said region of interest, a first quantization step, lower than or equal to said setpoint quantization step; determining a second quantization step higher than or equal to said setpoint quantization step and lower than or equal to a third quantization step such that the number of bits required by the region of interest is lower than the number of bits saved on the potential masking region; and assigning, when such a second quantization step exists, said second quantization step to said potential masking region, otherwise assigning said third quantization step to said potential masking region.

Abstract: 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.