Patent application number | Description | Published |
20110274158 | Method and Apparatus of Adaptive Loop Filtering - In a block-based motion compensated system, coding noises may arise due to lossy operations such as quantization. Deblocking is often used to alleviate visibility of coding artifacts by applying filtering across block boundaries adaptively. In the recent HEVC development, adaptive loop filtering (ALF) is being adopted to process deblocked reconstruction frames. Adaptive loop filtering is applied to reconstructed video data across multiple frames to reduce visibility of coding artifacts in the temporal domain. In a HEVC system, conventional ALF can be selectively turned ON or OFF for each block in a frame or a slice. The advanced ALF disclosed here allows a choice of multiple filter sets that can be applied to the reconstructed video data adaptively. Furthermore, the advanced ALF adopts a new unit for the filtering process to apply so that more flexible and/or localized processing can be provided. Furthermore, the advanced ALF allows a decoder to derive respective information for applying the filtering process without side information. | 11-10-2011 |
20110305274 | APPARATUS AND METHOD OF ADAPTIVE OFFSET FOR VIDEO CODING - An apparatus and method for content adaptive offset restoration are described. In video processing system, due to various mathematic operations applied to the data, the mean intensity of the processed video data may be shifted from mean intensity of original data. The intensity offset will result in noticeable artifacts. Accordingly adaptive offset restoration is disclosed which derives intensity offset for a region of a picture based on the dynamic characteristics of underlying pixels. According to the characteristics measurement of underlying pixels, the pixels in each region are classified into classes and an intensity offset is determined for each class. The characteristics measurement may be based on pixel patterns at an underlying pixel and the characteristics may be related to edge, peak and valley at the underlying pixel. Alternatively, the characteristics measurement may be based on pixel intensity of an underlying pixel and the pixel intensity is partitioned into multiple bands for classification. | 12-15-2011 |
20110305277 | SYSTEM AND METHOD FOR CONTENT ADAPTIVE CLIPPING - A system and method of content adaptive pixel intensity processing are described. In video processing system, due to various mathematic operations applied to the data, the processed video data may be become exceeding a range of original data and result in artifacts. Content adaptive clipping method is disclosed which takes into account the dynamic characteristics of the video data. Accordingly the method configures the video data into a predefined set which can be a partial picture, a frame or a group of frames. The data range of the original associated with the predefined set is determined The processed video data is clipped according to the range computed for the predefined set. | 12-15-2011 |
20120039383 | CODING UNIT SYNCHRONOUS ADAPTIVE LOOP FILTER FLAGS - An apparatus and method for coding unit-synchronous adaptive loop filtering (ALF) for an image area that is partitioned into a plurality of coding units are disclosed. In a conventional approach, the slice-level bitstream cannot be generated until all coding units in a slice are processed since the ALF filter coefficients are determined based on reconstructed pixels and original pixels of a slice. According to one embodiment, the method processes the coding units in the image area one after the other to generate a CU-level bitstream. The method also reconstructs the coding units to from reconstructed coding units which are subject to adaptive loop filtering. Upon the availability of reconstructed coding units for the image area, the method derives filter coefficients for the ALF filter based on the reconstructed pixels and original pixels in the image area. The designed ALF filter is then tested for each coding unit to determine whether the ALF filter should be applied to the coding unit and the decision is indicated by an ALF flag. After all ALF flags are determined, an image area header is created by incorporating the filter coefficients and ALF flags in the header. The header and the CU-level data previously created are combined into an image area level bitstream. An apparatus to perform the steps recited in the method is also disclosed. | 02-16-2012 |
20120082241 | Method and Apparatus of Adaptive Loop Filtering - A method and apparatus for processing in-loop reconstructed video using an in-loop filter is disclosed. In the recent HEVC development, adaptive loop filtering (ALF) is being adopted to process in-loop reconstruction video data, where ALF can be selectively turned ON or OFF for each block in a frame or a slice. An advanced ALF is disclosed later that allows a choice of multiple filter sets that can be applied to the reconstructed video data adaptively. In the present disclosure, pixels of the in-loop reconstructed video data are divided into a plurality of to-be-filtered regions, and an in-loop filter from a filter set is determined for each to-be-filtered region based on a rate-distortion optimization procedure. According to one embodiment of the present invention, computation of cost function associated with the rate-distortion optimization procedure is related to correlation values associated with original video data and the in-loop reconstructed video data. Furthermore, the correlation values can be shared by the multiple candidate filters during the rate-distortion optimization procedure for said each to-be-filtered region. In another embodiment, the correlation values can be shared by multiple candidate to-be-filtered regions of an area of the in-loop reconstructed video data during the rate-distortion optimization procedure for the area of the in-loop reconstructed video data. | 04-05-2012 |
20120082244 | Method and Apparatus of Region-Based Adaptive Loop Filtering - In a block-based motion compensated system, coding noises may arise due to lossy operations. Adaptive loop filter (ALF) is a technique used to improve the quality. A pixel adaptive (PA) ALF method was developed that uses the Sum-modified Laplacian Measure (SLM) to classify pixels and applies a respective ALF filter to each pixel according to the SLM. While the PA ALF achieves better performance over a conventional single filter (SF) based ALF, the PA ALF causes higher complexity and consumes more power due to the high complexity and per-pixel filter switching. Accordingly region based ALF scheme is disclosed which allows adaptive filter selection on a region by region basis and does not require per-pixel filter switching. In one embodiment according to the present invention, a picture is divided into M×N regions. The region based ALF also allows region merging for the M×N regions to improve performance. In another aspect of the present invention, the optimal ALF design also takes into consideration of the system complexity by using rate-distortion-complexity optimization (RDCO). The RDCO technique is also applied to sample adaptive offset (SAO) design. | 04-05-2012 |
20120106622 | Method and Apparatus of Slice Grouping for High Efficiency Video Coding - In the H.264/AVC standard, one of the new characteristics is the possibility of dividing an image in regions called slice groups. The use of slice groups provides various possible advantages such as prioritized transmission, error resilient transmission, and etc. The slice groups can be formed by flexible macroblock ordering (FMO), where each picture can be divided into slice groups in different scan patterns of the macroblocks. In the high efficiency video coding (HEVC) under development, a more flexible block structure, called coding unit (CU), is used as the unit to process video data. The picture is first divided into largest CUs (LCUs) and each LCU is adaptively split into smaller CUs using a quadtree until leaf CUs are reached. In the current HEVC development, there is neither slice nor slice group structure being considered. The LCU size used for HEVC is 16 times as large as the macroblock size used in the H.264/AVC standard. Therefore, it is very desirable to develop slice and slice group structure suited for HEVC to offer various benefits of error resilience, parallel processing, reduced line (row) buffer requirement, and etc. Accordingly, slice group types including raster scan type, vertical stripe type, regions of interest type and full flexibility type are developed for HEVC. Furthermore, various syntax elements are incorporated in the sequence header or the picture header to convey information associated with the slice group structure. | 05-03-2012 |
20120106624 | Method and Apparatus of Slice Boundary Filtering for High Efficiency Video Coding - An apparatus and method for video coding having intra-slice deblocking, intra-slice adaptive loop filter, and intra-slice adaptive offset are disclosed. In a video coding system, a picture is often divided into slices and each slice is independently processed so that errors or missing data from one slice cannot propagate to any other slice within the picture. In the recent high efficiency video coding (HEVC) development, deblock filtering (DF), adaptive loop filter (ALF) and adaptive offset (AO) may be applied to reconstructed slices. When the processing is applied across slice boundaries, it may rely on pixels outside the current slice and cause dependency of the current slice on other slice(s). Consequently, the DF/ALF/AO processing on a reconstructed slice may have to wait until the reconstructed slices that it is dependent from complete the DF/ALF/AO processing. To overcome the slice boundary issue, intra-slice DF/ALF/AO is developed that does not rely on any pixel outside the currently slice. An optional slice boundary filter may be applied to slice boundaries after all slices are processed by the intra-slice DF/ALF/AO. | 05-03-2012 |
20120106652 | Apparatus and Method for High Efficiency Video Coding Using Flexible Slice Structure - An apparatus and method for video coding based on flexible slice structure are disclosed. In the recent high efficiency video coding (HEVC) development, the slice may contain multiple LCUs instead of macroblocks. The LCU size being considered is 64×64 pixels which is much larger than the macroblock size of 16×16 pixels. Compared with the macroblock aligned slice for H.264, the LCU-aligned slice for HEVC does not provide enough granularities for dividing video frames. Consequently, a flexible slice structure is developed where slice partition is based on smaller coding units. In the flexible slice structure, the first LCU and the last LCU of the slice are allowed to be a fractional LCU, which is derived from a whole LCU using quadtree partition. Syntax elements are also developed to enable conveyance of flexible slice structure between an encoder and a decoder efficiently. | 05-03-2012 |
20120114034 | Method and Apparatus of Delta Quantization Parameter Processing for High Efficiency Video Coding - In the current high efficiency video coding development, each LCU has its own quantization parameter (QP) and the difference between a current QP and a reference QP is transmitted instead of the QP value itself. Since the LCU is much larger than the macroblock of AVC/H.264, using one delta QP per LCU may cause rate control unable to adapt to the bitrate quickly enough. Consequently there is a need to adopt delta QP in units smaller than LCU to provide more granular rate control. Furthermore, it is desirable to develop a system that is capable of facilitating more flexible delta QP. Accordingly, adaptive quantization parameter processing is disclosed where a QP minimum CU size for incorporating or deriving a delta QP is indicated selectively in the slice level or in the sequence/picture level. In one variation, the delta QP is incorporated or derived only if nonzero quantized transform coefficients exist in a leaf CU that is larger than the QP minimum CU size. In another variation, quantization parameter information is only incorporated or derived when a leaf CU has any nonzero quantized transform coefficient. In yet another variation, a flag is used to indicate whether one delta QP per LCU is transmitted if the LCU has any nonzero quantized transform coefficient or one delta QP per leaf CU is transmitted if the leaf CU has any nonzero quantized transform coefficient. | 05-10-2012 |
20120177103 | APPARATUS AND METHOD OF EFFICIENT SAMPLE ADAPTIVE OFFSET - For sample adaptive offset, classification may be used to classify the pixels into multiple categories and pixels in each category are offset compensated using an offset value for the category. The classification may be based on values of the current pixel and its neighboring pixels before SAO compensation. Therefore, the SAO compensated pixel cannot be written back to the current pixel location until the category for all pixels are determined. An embodiment of the present invention stores the relation between the current pixel and said one or more neighboring pixels so that the SAO compensated current pixel can replace the current pixel without buffering the to-be-processed pixels for classification. The SAO process may be performed on a region by region basis to adapt to the local characteristics of the picture. Rate-distortion optimization (RDO) is often used to guide the mode decision, such as region splitting/region merging decision. Computations associated with the RDO process usually are very computational intensive. Accordingly, distortion reduction estimation is developed which can substantially reduce the required computation associated with RDO. | 07-12-2012 |
20120177107 | Apparatus and Method of Sample Adaptive Offset for Video Coding - An apparatus and method for sample adaptive offset to restore intensity shift of processed video data are described. In a video coding system, the video data are subject to various processing such as prediction, transformation, quantization, deblocking, and adaptive loop filtering. Along the processing path in the video coding system, certain characteristics of the processed video data may be altered from the original video data due to the operations applied to video data. For example, the mean value of the processed video may be shifted. Therefore, the pixel intensity shift has to be carefully compensated or restored to alleviate the artifacts. Accordingly a sample adaptive offset scheme is disclosed that can take into consideration of the dynamic characteristics within a frame using a region partition scheme. Furthermore, the sample adaptive offset scheme also supports multiple SAO types that can be tailored to the characteristics of processed video data and achieve better quality. | 07-12-2012 |
20120207227 | Method and Apparatus for Slice Common Information Sharing - A method and apparatus for sharing information in a video coding system are disclosed. Embodiments according to the present invention use an information sharing flag to determine whether to share in-loop filter information in the picture level. The information sharing flag may be incorporated in the sequence level, the picture level or the slice level to indicate whether information sharing is enabled. Multiple information sharing flags may also be used to adaptively control information sharing. Furthermore, method and apparatus of using multiple Adaptation Parameter Sets (APSs) for information sharing of in-loop filters are disclosed. APS identifiers of in-loop filters may be incorporated in the slice header to allow each of the in-loop filters select respective filter information from the multiple APSs. A flag is incorporated in SPS to indicate whether multiple APS or single APS is used. Various exemplary syntax designs are disclosed to illustrate information sharing. | 08-16-2012 |
20120294353 | Apparatus and Method of Sample Adaptive Offset for Luma and Chroma Components - A method and apparatus for processing reconstructed video using in-loop filter in a video coding system are disclosed. The method uses chroma in-loop filter indication to indicate whether chroma components are processed by in-loop filter when the luma in-loop filter indication indicates that in-loop filter processing is applied to the luma component. An additional flag may be used to indicate whether the in-loop filter processing is applied to an entire picture using same in-loop filter information or each block of the picture using individual in-loop filter information. Various embodiments according to the present invention to increase efficiency are disclosed, wherein various aspects of in-loop filter information are taken into consideration for efficient coding such as the property of quadtree-based partition, boundary conditions of a block, in-loop filter information sharing between luma and chroma components, indexing to a set of in-loop filter information, and prediction of in-loop filter information. | 11-22-2012 |
20130128986 | Method and Apparatus of Slice Boundary Padding for Loop Filtering - A method and apparatus for video processing of reconstructed video in a reconstruction loop are disclosed. An embodiment according to the present invention performs padding for the blocks in the slice boundaries according to a processing order. Each of the one or more reconstructed blocks at slice boundaries is padded according to a padding order. In-loop filtering is applied to the reconstructed slice according to the processing order, wherein the reconstructed slice is filtered by referencing the one or more padded blocks. The padding order can be vertical-edge first and then horizontal-edge, or horizontal-edge first and then vertical-edge. Various embodiments are disclosed regarding whether padding for a later padded block in the processing order is skipped or not in the overlapped area. The present invention is also applied to adaptation blocks for block-based in-loop filtering in slice boundaries. | 05-23-2013 |
20130215959 | Method of Filter-Unit Based In-Loop Filtering - Methods for filter-unit based in-loop filtering in a video decoder and encoder are disclosed. In one embodiment, filter parameters are selected from a filter parameter set for each filter based on a filter index. In another embodiment, the picture is partitioned into filter units according to filter unit size, which can be selected between a default size and other size. When other size is selected, the filter unit size may be conveyed using direct size information or ratio information. In another embodiment, a merge flag and a merge index are used to convey filter unit merge information. A method for filter-unit based in-loop filtering in a video encoder for color video is disclosed. In one embodiment, the method incorporates filter syntax in the video bitstream by interleaving the color-component filter syntax for the FUs. | 08-22-2013 |
20130259117 | Method and Apparatus of Adaptive Loop Filtering - A method and apparatus for processing of coded video using adaptive offset (AO) are disclosed. Embodiments of the present invention divide reconstructed video data into multiple filter units and apply adaptive offset to the filter units to generate filtered video data, where boundaries of filter units correspond to boundaries of coding units and each of said filter units contains at least one coding unit. Furthermore, two or more of the multiple filter units can be merged as indicated by a merge index to share the applied adaptive offset. A filter control flag can be used to indicate filter ON/OFF control. The luma and chroma components may also share the same filter information. In another embodiment, the filter information sharing among filter units can be applied regardless whether the boundaries of the filter units are aligned with the boundaries of the coding units. | 10-03-2013 |
20130322523 | METHOD AND APPARATUS FOR REDUCTION OF IN-LOOP FILTER BUFFER - A method and apparatus for in-loop processing of reconstructed video are disclosed. The method and apparatus configure the in-loop processing so that the processing requires no pixel or reduced pixels from other side of a virtual boundary. When the in-loop processing of the to-be-processed pixel requires a pixel from the other side of the virtual boundary, the pixel from the other side of the virtual boundary is replaced by a replacement pixel. The in-loop processing can also be configured to skip the pixel when the processing requires a pixel from other side of the virtual boundary. The in-loop processing can also be configured to change ALF filter shape or filter size when the in-loop processing requires a pixel from other side of the virtual boundary. A filtered output can be combined linearly or nonlinearly with the to-be-processed pixel to generate a final filter output. | 12-05-2013 |
20130329784 | Method and Apparatus for Line Buffer Reduction for Video Processing - A method and apparatus of line buffer reduction for context adaptive entropy processing are disclosed. The context formation for context adaptive entropy processing depends on block information associated with one or more neighboring Determining context formation for processing a blocks. When the neighboring block is on a different current syntax element of a current block in a region, side of a region boundary from the current block, the wherein the context formation depends on block block information is replaced by replacement block information associated with a neighboring block information to reduce or remove line buffer requirement for storing the block information of neighboring blocks on the other side of the region boundaries from the current block. The context adaptive entropy Replacing the block information associated with a processing is CABAC encoding, CABAC decoding, neighboring block by replacement block information if CAVLC encoding, or CAVLC decoding. | 12-12-2013 |
20140003495 | Method and Apparatus of Scalable Video Coding | 01-02-2014 |
20140072033 | Method and Apparatus of Scalable Video Coding - A method and apparatus for scalable video coding are disclosed, wherein the video data is configured into a Base Layer (BL) and an Enhancement Layer (EL) and wherein the EL has higher spatial resolution or better video quality than the BL. According to embodiments of the present invention, information from the base layer is exploited for coding the enhancement layer. The information coding for the enhancement layer includes CU structure, motion information, motion information, MVP/merge candidates, intra prediction mode, residual quadtree information, texture information, residual information, context adaptive entropy coding, Adaptive Lop Filter (ALF), Sample Adaptive Offset (SAO), and deblocking filter. | 03-13-2014 |
20140086323 | METHOD AND APPARATUS FOR CODING OF INTRA PREDICTION MODE - Embodiments according to the present invention configure the intra prediction mode candidates into multi-level MPM sets, which comprise at least a first-level MPM set and a second-level MPM set. Encoding or decoding a current intra prediction mode is based on the multi-level MPM sets, where one syntax element of the syntax information to be generated or decoded respectively is associated with evaluating the current intra prediction mode using the first-level MPM set. A method and apparatus for spectively is associated with evaluating the current intra prediction mode using the first-level MPM set. A method and apparatus for chroma intra prediction mode encoding and decoding are also disclosed. The chroma intra prediction mode set includes a Luma-based chroma prediction Mode (LM), a Direct Mode (DM) and four other modes. The codeword set comprises variable-length codewords and fixed-length codewords, and the fixed-length codewords are longer than the variable-length codewords. The variable-length codewords are used for the DM and LM, and the fixed-length codewords are used for the four other modes. | 03-27-2014 |
20140146891 | Method and Apparatus of Scalable Video Coding - A method and apparatus for scalable video coding are disclosed, wherein the video data is configured into a Base Layer (BL) and an Enhancement Layer (EL) and wherein the EL has higher spatial resolution or better video quality than the BL. According to embodiments of the present invention, information from the base layer is exploited for coding the enhancement layer. The information coding for the enhancement layer includes CU structure, motion information, motion information, MVP/merge candidates, intra prediction mode, residual quadtree information, texture information, residual information, context adaptive entropy coding, Adaptive Lop Filter (ALF), Sample Adaptive Offset (SAO), and deblocking filter. | 05-29-2014 |
20140192861 | METHOD AND APPARATUS FOR REORDERED BINARIZATION OF SYNTAX ELEMENTS IN CABAC - A method and apparatus of context-based adaptive binary arithmetic encoding/decoding for syntax elements of one or more blocks are disclosed. According to one embodiment of the present invention, the binarization results of the x and y positions of the last significant coefficient of a transform unit are reordered by collecting the bypass bins together. According to another embodiment of the present invention, binarization results of syntax elements from two or more of four Intra N×N prediction units, including prev_intra_luma_pred_flag, rem_intra_luma_pred_mode, and mpm_idx are reordered by collecting the bypass bins together. In yet another embodiment according to the present invention, the binarization results of other syntax elements are also reordered by collecting bypass bins together. Furthermore, the above reordering of binarization results may be used for binarization results corresponding to a block and its neighboring blocks. | 07-10-2014 |
20140198840 | METHOD AND APPARATUS FOR ADAPTIVE LOOP FILTER WITH CONSTRAINED FILTER COEFFICIENTS - Methods and apparatuses for processing of coded video using ALF are disclosed. Embodiments according to the present invention apply ALF with constrained data range to reconstructed video data. The ALF parameters comprise a center coefficient, one or more non-center coefficients, and an offset term. As an example, the constrained data range for the center coefficient is selected from [0.0, 2.0) and [0.5, 1.5). In another example, the constrained data range for said one or more non-center coefficient is selected from [−1.0, 1.0) and [−0.5, 0.5). The constrained data range can also be applied to the offset term. For example the range of [−2 | 07-17-2014 |
20140247884 | METHOD AND APPARATUS FOR MV SCALING WITH INCREASED EFFECTIVE SCALING RATIO - A method and apparatus for deriving a scaled MV (motion vector) for a current block based on a candidate MV associated with a candidate block are disclosed. Embodiments according to the present invention increase effective scaling factor of motion vector scaling. In one embodiment, a distance ratio of a first picture distance between a current picture and a target reference picture pointed to by a current motion vector of the current block to a second picture distance between a candidate picture corresponding to the candidate block and a candidate reference picture pointed to by the candidate MV is computed. The scaled MV is then generated based on the candidate MV according to the distance ratio, where the scaled MV has an effective scaling ratio between −m and n, and wherein m and n are positive integers greater than 4. The values of m and n can be 8, 16 or 32. | 09-04-2014 |
20150016506 | METHOD AND APPARATUS FOR LOOP FILTERING ACROSS SLICE OR TILE BOUNDARIES - A method and apparatus for loop filter processing of video data in a video encoder or decoder are disclosed. Embodiments according to the present invention conditionally allow sharing of loop filter parameters. In one embodiment, sharing of loop filter information between the current block and a neighboring block is determined according to a condition. If the condition indicates that sharing of loop filter information is allowed, a merge flag is coded and incorporated in the video bitstream in an encoder, and a merge flag is parsed from the video bitstream and decoded in a decoder. In one embodiment, the condition depends on region partitioning of the picture, where region partitioning partitions the picture into regions and the region may correspond to a slice or a tile. The condition is set to indicate that sharing of loop filter information is allowed if the block and the neighboring block are in a same slice/tile. | 01-15-2015 |