摘要:
In video encoding, the video frames are spatio-temporally filtered for reduction of spatial and temporal redundancy before they are entropy encoded. Known filtering schemes consider temporally successive frames and are static. It is probable but not necessary that successive frames are most efficient to encode. Therefore, a plurality or all possible frame order permutations are considered for a group of frames (GOP) and evaluated based on a global criterion, which is the sum of local criterion values computed over disjoint sets of successive frames considered in the new order. The local criterion value is deduced from motion estimation processed on each considered set of frames. The best ordering is chosen as the one that minimizes the global criterion value.
摘要:
The process for coding the current block comprises a step of selecting the predicted block (2) from among candidate blocks, the selection being dependent on a difference D B drx,dry between the co-located block of the current image block lying in an image of type B and the block of a reference image, the latter block being designated by the motion vector with components drx, dry which is allocated to the co-located block and which is colinear with the motion vector Vp allocated to the current block and designating the candidate block. Applications relate to data compression, the transmission of digital images using the video coding standard comprising a direct prediction mode, for example the h263, MPEG4 or h261 standard.
摘要:
The invention relates to a process for coding images transmitted according to the so-called multiresolution technique. According to this process, a step of pixel level processing of so-called mixed blocks of pixels, that is to say those shared between at least one zone of a first resolution and at least one zone of a second resolution, is performed. A block is thus transmitted, the pixels of whose zone of the first resolution are assigned this first resolution and the pixels of whose zone of second resolution are assigned this second resolution.
摘要:
A method for encoding an interlaced sequence of digital video data decomposes the interlaced video sequence (I) into first (F1) and second (F2) fields, performs digital filtering (SF1) to get lower frequency (L) and higher frequency (H) component signals of the first fields (F1), and uses spatio-temporal filtering (STF) and motion estimation (ME1) for generating base layer signals (P, MV1) being suitable for reconstruction of a progressive mode video sequence (V1,V2) in a receiver. Advantageously, both the spatio-temporal filter (STF) at the encoder, and the inverse process (STS) at the receiver, can perform scaling in spatial and temporal dimension. The second fields (F2) are used to generate enhancement signals (FF2, MV2), which enable a receiver to reproduce an interlaced video sequence of the full, or scaled, spatial and/or temporal resolution.
摘要:
The process is characterized in that it performs the inverse operations (26, 27, 28) of the successive coding operations, in an inverse order, coefficient by coefficient rather than block by block. Applications relate to the compression of video data.
摘要:
The invention relates to a device for coding two-dimensional images representing viewpoints of a three-dimensional virtual scene, a movement in this scene, simulated by the successive displaying of images, being limited according to predetermined trajectories. In accordance with the invention, the device is characterized in that it comprises means for coding a trajectory with the aid of a graph (300) of successive nodes N i such that with each node N i is associated at least one two-dimensional source and one transformation of this image.
摘要:
The present invention relates to a device (1) for inserting error correcting codes into data streams (11) intended to be sent in packets in a network (8), a device (9) for reconstructing data streams (13), and corresponding methods and products. The insertion device comprises a unit (3) for identifying resynchronization indicators dispersed in the data streams and a unit (4) for determining successive segments in these streams, the segments forming partitions of the data lying between two consecutive resynchronization indicators. It also comprises a unit (6) for allocating a set of error correcting codes to each of these segments, these sets of codes having decreasing sizes between any two of the consecutive resynchronization indicators. Preferably, the device also comprises a data interleaving unit (7).
摘要:
The process is characterized in that, for a coded pixel group to be converted, if the mode of coding used is of the inter type with no residue(6), the conversion is performed by a copy (8, 10) of a converted pixel group of a preceding image (11) linked by the motion vector associated with said coded pixel group. Applications relate to the displaying and composing of images.