219 results about "Intra mode" patented technology

A method and apparatus for Intra prediction mode encoding or decoding based on multi-level most probable modes (MPMs) are disclosed. In one embodiment according to the present invention, the method and apparatus for encoding or decoding Intra prediction mode for 4×4 prediction unit (PU) use 19 Intra mode candidates to have full directional coverage or 35 Intra mode candidates as used by 8×8, 16×16 and 32×32 PUs. In another embodiment of the present invention, three MPMs are used to code the Intra modes. Various methods to derive the three MPMs based on the Intra modes of neighboring blocks are disclosed. In yet another embodiment of the present invention, the coding method for the remaining modes comprises fixed length coding. In addition, variable length coding for the remaining modes are also disclosed.

The temporal and / or spatial characteristics of a macroblock are analyzed in order to reduce the number of modes for which motion estimation and rate distortion efficiency calculations are to be performed. In one embodiment, macroblock mean and variance characteristics are analyzed to merge sub-blocks together within the macroblock. These merged sub-blocks may be used to identify both inter and intra modes for the macroblock.

The invention relates to a method and device for encoding digital video data corresponding to an original sequence of images and available in the form of a video stream consisting of successive pictures which are either INTRA pictures or INTER pictures. The INTRA pictures are called I-pictures and encoded by means of a so-called INTRA mode without any reference to any past or future picture. The INTER pictures are either monodirectionally predicted pictures, called P-pictures and encoded with reference to a past or future reference picture which is an INTRA or INTER picture, or bidirectionally predicted pictures, called B-pictures and encoded with reference to one or more reference picture(s). The INTRA pictures themselves comprise either I-pictures placed at the beginning of a new group of pictures corresponding to a scene change, where no temporal redundancy is available, and called scene change I-pictures, or I-pictures placed in other locations, where some temporal redundancy is available, and called refresh pictures. According to the invention, the method is characterized in that, before being quantized and encoded in INTRA mode, said INTRA refresh pictures are replaced by an INTER picture having quality and artefacts substantially similar to those of the last encoded INTER picture(s).

The invention discloses a fast and efficient video coding intra mode determining method. The fast and efficient video coding intra mode determining method includes the steps of prediction manner configuration and prediction mode selection. According to the prediction mode selection, the correlations between brightness intra prediction modes of a current CU layer and brightness intra prediction modes of CU layers above the current CU layer, the correlation between CBF and TU segmentation depth, and the correlations between chroma intra prediction modes of adjacent CU layers are utilized, and redundant intra mode prediction can be skipped, and therefore, coding computation complexity can be decreased. According to the correlation between a cost function and RDcost and the correlations between chroma intra prediction modes and brightness intra prediction modes, a minimum-cost prediction mode and an optimal brightness prediction mode in RMD are added in a brightness and chroma intra prediction process, and therefore, video coding efficiency and video quality can be ensured. Compared with high efficiency video coding (HEVC) standards in the prior art, the fast and efficient video coding intra mode determining method of the invention can greatly decrease coding computation complexity under the premise that bit rate and video quality are almost unchanged.

A method and apparatus for video coding of chroma coded in derived-mode Intra prediction are disclosed. If derived-mode (DM) Intra prediction is selected for a current chroma block, a corresponding luma block area is determined by locating a first upper-left pixel address of the corresponding luma block area corresponding to that of the current chroma block; one or more candidate luma coding modes are determined from a sub-block set consisting of one or more sub-blocks of the corresponding luma block area, where if the sub-block set consists of only one sub-block, the sub-block set excludes a corner sub-block located at a top-left corner of the corresponding luma block area; a current chroma Intra mode for the current chroma block is derived based on information comprising the candidate luma coding modes; and Intra-prediction encoding or decoding is applied to the current chroma block using the current chroma Intra mode derived.

Provided is a method for decoding video, which performs prediction in an intra mode. The method for decoding video according to the invention comprises steps of: creating a current table index using a code number and MPM index information; and deriving a current prediction mode by adopting an index mapping table in the current table index. According to the present invention, video encoding / decoding efficiency can be improved.

A prediction mode for encoding data is selected using a reduced number of rate-distortion cost computations. This reduction in rate-distortion cost computations is caused by filtering the number of potential intra prediction modes based on two criteria. First, the number of potential prediction modes is reduced based on at least one characteristic of a quantization procedure performed during the encoding procedure. Second, the number of potential prediction modes is reduced based on an error value calculated for each of the potential prediction modes.

A video encoder / decoder utilizes a bistream syntax that provides an independently decodable, partial picture unit, which may be in the form of a unit containing one or more contiguous rows of macroblocks (called a slice). This slice layer provides a flexible combination of error-resilience and compression efficiency. The slice layer encodes an efficient addressing mechanism (e.g., a syntax element specifying a beginning macroblock row of the slice layer), as well as an efficient mechanism to optionally retransmit picture header information. The slice layer provides decoding and reconstruction independence by disabling all forms of prediction, overlap and loop-filtering across slice-boundaries. This permits a slice coded in intra-mode to be reconstructed error-free, irrespective of errors in other regions of the picture.

Disclosed herein is an adaptive motion estimation and mode decision apparatus and method for an H.264 video codec. The apparatus includes a background image detection unit, an inter mode inspection unit, an intra mode inspection unit and a mode inspection skip unit. The background image detection unit inspects whether a fixed background or slowly and regularly moving block exists, and skips the step of dividing a first corresponding macroblock into smaller sized blocks and performing block mode inspection. The inter mode inspection unit inspects whether an irregularly or fast moving macroblock exists, and determines whether to divide a corresponding macroblock into smaller sized blocks and to perform block mode inspection on the smaller sized blocks. The intra mode inspection unit performs AZCB inspection on the macroblocks, and determines whether to divide a corresponding macroblock into smaller sized blocks block and to perform mode inspection on the smaller sized blocks. The mode inspection skip unit skips the block mode inspection for the smaller sized blocks.

A method and device for coding a digital image using intra-mode block prediction, wherein a list of prediction modes for each combination of prediction modes of the neighboring blocks is obtained. The modes assigned to each combination of prediction modes may be divided into two groups. The first group includes n (where n is smaller than the overall number of available modes) most probable prediction modes and the second group includes the remaining modes. The modes in the first group are ordered according to their probability. This order may be specified as a list of modes ordered from most probable to the least probable mode. The modes belonging to the second group may be ordered in some predetermined manner, which may be specified depending on the information already available to the decoder.

A video signal coding method is provided which finds proper decision curves according to characteristics of input frames and encodes the optimal macroblock by using the decision curves instead of a fixed motion / no-motion compensation curve and intra / inter coding curve. The optimal mode is selected for each macroblock of input frame and it is determined through a step of judging whether the input frame is intra mode using a given function, a step of judging whether the input frame is inter mode when it is not intra mode using a given function, a step of controlling quantizer using a predetermined critical value when it is not inter mode, and step of performing skip when the quantizer controlling step is not carried out.

A method and apparatus are provided for effectively predicting a video frame that use all of the advantages of an intra mode and an intra BL mode in multi-layer structure based-video coding. The method includes reconstructing the intra block of a lower layer using the previously reconstructed first neighboring blocks of the intra block; subtracting the first neighboring blocks from previously stored the second neighboring blocks of an upper layer corresponding to the first neighboring blocks; creating a differential predicted block based on a predetermined intra prediction mode by performing intra prediction using virtual differential neighboring blocks that are created as a result of the subtraction; adding the differential predicted block and the reconstructed intra block; and subtracting a predicted block, which is created as a result of the addition, from a block of the upper layer corresponding to the intra block.

The vector detecting unit detects a motion vector even for a block that is encoded in the intra mode, and the detected motion vector is stored in the reference vector storing unit. Even for a block that has been encoded in the intra mode, the initial vector calculating unit calculates an initial point with the use of a reference vector, the initial point serving as an initial point used in a motion vector detection process during hierarchical block matching. Thus, it is possible to calculate an initial point with a high precision level with the use of motion information from the vicinity of a target block for which a motion vector is to be detected.