摘要:
The invention proposes a digital signal coding method including a step (E1) of analysing the digital signal (IM) into a plurality of frequency sub-bands, at least one first sub-band having a lower frequency and at least one second sub-band having a higher frequency, characterised in that it includes, for each second sub-band, the steps of: dividing (E4) the second sub-bands into blocks (Bp,n), selecting (E9) first blocks which are to be coded by setting to a predetermined value and second blocks which are to be coded by trellis coded quantization, according to a selection criterion, linking (E16) the second blocks selected at the previous step in order to form a series of blocks, coding (E17) the series of blocks by trellis coded quantization of a series of coefficients extracted from the second blocks of the second sub-band.
摘要:
The method of coding a digital image, comprising a step of coding in a format comprising a lower definition layer and at least one higher definition layer further comprises: a step of determining at least one data rate and/or at least one distortion corresponding to a target definition between the lower definition and a higher definition and a step of associating, with the result of the coding step, information representing at least one data rate and/or at least one distortion corresponding to a target definition.
摘要:
Motion vectors of a first reference frame are permitted to point to a plurality of further reference frames. A method of storing the motion vectors comprises, when a block of the first reference frame has two motion vectors initially, selecting one of the two motion vectors, the non-selected motion vector not being stored. The selected motion vector may be scaled. This can reduce the motion vector memory size.
摘要:
Reference prediction mode values, also referred to as most probable modes, usable for encoding or decoding of a prediction mode related to a current coding unit, are derived. First and second reference prediction mode values are derived (S402) from respective prediction modes of at least two neighboring coding units of the current coding unit. The first and second reference prediction modes are different. A third reference prediction mode value is derived (S403) from the first and second reference prediction mode values. The third reference prediction mode is different from each of said first and second reference prediction mode values.By deriving three MPMs instead of two for comparison with the prediction mode of the current coding block the coding efficiency is improved. This is due to the increase in the probability that the prediction mode of the current coding block corresponds to one of the derived most probable modes.
摘要:
A temporal motion vector predictor is includable, together with one or more spatial motion vector predictors, in a set of motion vector predictors for a block to encode of a current frame. A method of determining the temporal motion vector predictor comprises selecting as the temporal predictor one motion vector from among motion vectors in a reference block of a reference frame different from the current frame. The reference block is a block of the reference frame collocated with the block to encode or a block of the reference frame neighboring the collocated block. The selection is based on a diversity criterion for achieving diversity among the predictors of the set.This can reduce the motion vector memory requirements with no or no significant additional coding efficiency penalty. Alternatively, even if the motion vector memory is not reduced in size, coding efficiency improvements can be achieved.
摘要:
A method and device for deriving motion information of an image portion of an image predicted by motion prediction with respect to at least one reference image, the method comprising for said image portion: obtaining a number i of motion information predictors 808 of a second set of motion information predictors 814 taken from a first set of motion information predictors for decoding the image portion; generating said second set of motion information predictors 814 consisting of said number i of motion information predictors, wherein there are no duplicates among the i motion information predictors of said second set. A method and device for of decoding a bitstream, and a method and device for encoding a sequence of image including a method for deriving motion information of an image portion of an image predicted by motion prediction with respect to at least one reference image as described above.
摘要:
The present invention concerns a method of coding a plurality of digital image signals in a bitstream, said signals each corresponding to a view of a scene, the said coding method comprising the use of a pre-determined predictive coding structure, the views being associated with input views in the coding structure. The coding method according to the invention comprises, for at least one pair of views of the scene, steps of determining a spatial intersection zone (E44) and of calculating a value representing the similarity between the signals corresponding to said views (E45), according to at least some of the signals contained in said spatial intersection zone. These steps are followed by a step of associating (E46) at least one view with an input view of the predictive coding structure according to at least one calculated similarity value. The invention applies both to fixed image signals and to image sequences.
摘要:
The method of processing a sequence of digital images, in the context of coding according to a bit stream comprising compressed output images organized according to at least two temporal hierarchy levels in accordance with a predetermined scalable format, comprises the following steps: obtaining and storing original images, and generating output images, by the transformation of original images and/or intermediate images, and/or output images, in a first chosen order so that the number of images to be stored, simultaneously necessary for the transformation of the original images into output images, is minimal.
摘要:
To identify data losses in a video sequence transmitted between a server and at least one client over a communication network, the sequence comprising a plurality of video data containers coded using scalable video coding employing a predetermined number of hierarchical levels, the video data containers being transmitted over the network via a series of data transport packets: a process (311) is carried out of detecting losses and of locating the video data affected by those losses, without decoding the video data, by combining information coming from transport packets and information coming from video data container headers.Application for improving decoding on receiving a video sequence.
摘要:
The method of scalable coding of moving images using at least one reference image for at least one image to code, comprises, at least on passing, for a so-called “current” image, from an initial quality level to an intended quality level different from the initial quality level: a step (705) of coding the current image as far as the intended quality level to provide a coded current image, a step (710) of reconstructing the current image at the intended quality level to provide a reconstructed current image of intended quality level, a step (715) of obtaining at least one reference image of the current image at the initial quality level, to provide a prediction image for the initial quality level, a step (720, 725) of determining a differential texture refinement depending on the prediction image for the initial quality level and on the reconstructed current image of intended quality level and a step (730) of coding the differential texture refinement.