Abstract: The invention relates to a method of synchronizing first and second digital signals presenting digital elements to be put into correspondence, on the basis of time references. The method includes preliminary synchronization of the two digital signals using time references, by putting time references recognized as having the same value in the first and second digital signals into correspondence; and fine synchronization on the basis of a characteristic parameter obtained from the binary streams of the digital elements, and computed for each of the first and second digital signals.

Abstract: The invention relates to a method of transmitting an audio and/or video program via a transmission channel at adjustable bit rates, the method implementing an adjustment of at least one encoding and/or transmission parameter as a function of at least one setpoint vector having at least one dimension and representing a quality of reception desired by said end user.

Abstract: The invention provides a method of evaluating the quality of an audiovisual sequence by: a) training, comprising allocating a subjective score NSi to each of N0 training sequences Si (where i=1, 2, . . . , N0) presenting degradations identified by a training vector MO1 which is given to each sequence Si in application of a first vectorizing method, in order to build up a database of N0 training vectors MOi with subjective scores NS1; b) classifying the N0 training vectors MOi into k classes of scores as a function of the subjective scores NS1 that have been allocated to them, so as to form k training sets EA (where j=1, 2, . . . , k) which have k significant training scores NSRj allocated thereto; c) for each audiovisual sequence to be evaluated, generating a vector MO using said first vectorization method; and d) allocating to the audiovisual sequence for evaluation the significant training score NSRj that corresponds to the closest training set EAj.

Abstract: The invention concerns a method for synchronising a video image (IM) spatial position to find the position of an initial digital coding grid (GI), by said image (IM) coding blocks, characterised in that it consists in the following steps: a) moving along the direction of the image (IM) lines and/or along the direction perpendicular to the image (IM) lines, an analysis grid (GA) consisting of coding blocks and corresponding to at least part of the image (IM); b) determining for each position of the analysis grid (GA), the transformed coefficients Fu,v of each block of the analysis grid (GA), using a discrete cosine transform (TCD); and computing for each analysis grid (GA) position, an activity parameter (AM, ES) representing the image activity; c) determining the analysis grid (GA) position for which said activity parameter (AM, ES) has a minimal value.

Abstract: The invention concerns a method for assessing the degradation of a video image coded by blocks of picture elements or pixels, comprising the following steps: a) selecting an input image and determining its spatial activity (SA) in an analysis window according to the following sub-steps: i) determining for each block (n, m) the transformed coefficients Fn m (i, y) by a block transform; ii) determining from the transformed coefficients Fn, m (i, y) each block spatial activity bsa; iii) determining the analysis window global spatial activity SA1; b) selecting the output image corresponding to the input image and determining said global spatial activity SA2 of the output image; c) comparing the spatial activities (SA2) and (SA1)

Abstract: The invention relates to a method of synchronizing first and second digital signals presenting digital elements to be put into correspondence, on the basis of time references.