Abstract: Implementations of sample adaptive offset (SAO) processing a reconstructed picture in an image or video coding system are described. In one example implementation, a method may receive input data associated with the reconstructed picture. The method may also perform multiple stages of SAO filtering operations on a SAO processing unit of at least a portion of the reconstructed picture. Information related to a SAO parameter set that signals one or more SAO types, one or more SAO subtypes, one or more SAO offset values, or a combination thereof, used by the multiple stages of SAO filtering operations are encoded or decoded.

Abstract: A method and apparatus for encoding or decoding SAO (sample adaptive offset) parameters in a video encoder or decoder are disclosed. Embodiments according to the present invention encode or decode signs and magnitudes of SAO offset values separately for a region using band offset, where the signs are coded using bypass mode coding or fixed length coding. In one embodiment, the magnitudes of the SAO offset values for a region are grouped and coded together. If the SAO type is not band offset, the signs of the SAO offset values are omitted from the compressed data associated with the region. In another embodiment, the magnitude of the SAO offset value for band offset is checked to determine whether it is zero. If the magnitude of the SAO offset value is zero, there is no need to incorporate the sign of the SAO offset value in the compressed data.

Abstract: A method and apparatus for sharing information in a video decoding system are disclosed. The method derives reconstructed data for a picture from a bitstream, where the picture is partitioned into multiple slices. An information-sharing flag is parsed from the bitstream associated with a current reconstructed slice. If the information-sharing flag indicates information sharing, shared information is determined from a part of the bitstream not corresponding to the current reconstructed slice, and in-loop filtering process is applied to the current reconstructed slice according to the shared information. If the information-sharing flag indicates filter no information sharing, individual information is determined from a part of the bitstream corresponding to the current reconstructed slice, and in-loop filtering process is applied to the current reconstructed slice according to the individual information. A method for a corresponding encoder is also disclosed.

Abstract: 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.

Abstract: A method and apparatus for inter-layer prediction for scalable video coding are disclosed. Embodiments of the present invention utilize weighted prediction for scalable coding. The weighted prediction is based on the predicted texture data and the inter-layer Intra prediction data derived from BL reconstructed data. The inter-layer Intra prediction data corresponds to the BL reconstructed data or up-sampled BL reconstructed data. The predicted texture data corresponds to spatial Intra prediction data or motion-compensated prediction data based on the second EL video data in the same layer as the current EL picture. Embodiments of the present invention also utilize the reference picture list including an inter-layer reference picture (ILRP) corresponding to BL reconstructed texture frame or up-sampled BL reconstructed texture frame for Inter prediction of EL video data. The motion vector is limited to a range around (0,0) when the ILRP is selected as a reference picture.

Abstract: A motion prediction method is provided. The method has the following steps of: determining a plurality of candidate units corresponding to a current unit of a current frame; obtaining a plurality of motion vectors of the candidate units; calculating a plurality of temporal scaling factors of the candidate units according to a plurality of temporal distances between a plurality of reference frames of the motion vectors and the current frame; scaling the motion vectors of the candidate units according to the temporal scaling factors to obtain a plurality of scaled motion vectors; and selecting a motion vector predictor for motion prediction of the current unit from the candidate units according to the scaled motion vectors.

Abstract: An apparatus and method for sample adaptive offset (SAO) to restore intensity shift of processed video data are disclosed. In an encoder side, the processed video data corresponding to reconstructed video data, deblocked-reconstructed video data, or adaptive loop filtered and deblocked-reconstructed video data are partitioned into regions smaller than a picture. The region partition information is signaled in a video bitstream located in a position before intensity offset values syntax. At the decoder side, the processed video data is partitioned into regions according to the partition information parsed from the bitstream at a position before intensity offset values syntax. Region-based SAO is applied to each region based on the intensity offset for the category of the region-based SAO type selected.

Abstract: A method and apparatus for sample adaptive offset (SAO) compensation of reconstructed video data are disclosed. In one embodiment, the relation between the current pixel and said one or more neighboring pixels is stored 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.

Abstract: The invention provides a motion prediction method. First, a plurality of motion vector predictors is obtained to be included in a candidate set for motion prediction of a current unit of a current frame. Whether the current frame is a non-reference frame which is not referred to by other frames for motion prediction is then determined. When the current frame is not the non-reference frame, any motion vector predictor corresponding to a previously coded frame is removed from the candidate set, and a motion vector of the current unit is predicted according to the motion vector predictors of the candidate set.

Abstract: A method and apparatus for sharing context among different SAO syntax elements for a video coder are disclosed. Embodiments of the present invention apply CABAC coding to multiple SAO syntax elements according to a joint context model, wherein the multiple SAO syntax elements share the joint context. The multiple SAO syntax elements may correspond to SAO merge left flag and SAO merge up flag. The multiple SAO syntax elements may correspond to SAO merge left flags or merge up flags associated with different color components. The joint context model can be derived based on joint statistics of the multiple SAO syntax elements. Embodiments of the present invention code the SAO type index using truncated unary binarization, using CABAC with only one context, or using CABAC with context mode for the first bin associated with the SAO type index and with bypass mode for any remaining bin.

Abstract: 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.

Abstract: 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.

Abstract: A method of SAO (sample-adaptive offset) processing is disclosed, where EO classification is based on a composite EO type group. The composite EO type group comprises at least one first EO type from a first EO type group and at least one second EO type from a second EO type group. The first EO type group determines the EO classification based on the current reconstructed pixel and two neighboring reconstructed pixels, and the second EO type group determines the EO classification based on weighted outputs of the current reconstructed pixel and a number of neighboring reconstructed pixels. A method of inter-layer SAO processing is also disclosed. An inter-layer reference picture for an enhancement layer is generated from the BL reconstructed picture and the inter-layer SAO information is determined, where at least a portion of the inter-layer SAO information is predicted or re-used from the BL SAO information.

Abstract: A method and apparatus for 3D video coding system are disclosed. Embodiments according to the present invention apply SAO process (sample adaptive offset process) to at least one dependent-view image of the processed multi-view images if processed multi-view images are received. Also embodiments according to the present invention apply the SAO process to at least one dependent-view image of the processed multi-view images or at least one depth map of the processed multi-view depth maps if both processed multi-view images and the processed multi-view depth maps are received. The SAO can be applied to each color component of the processed multi-view images or the processed multi-view depth maps. The SAO parameters associated with a target region in one dependent-view image or in one depth map corresponding to one view may share or may be predicted by second SAO parameters associated with a source region corresponding to another view.

Abstract: 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.

Abstract: A method and apparatus for loop processing of reconstructed video in an encoder system are disclosed. The loop processing comprises an in-loop filter and one or more adaptive filters. The filter parameters for the adaptive filter are derived from the pre-in-loop video data so that the adaptive filter processing can be applied to the in-loop processed video data without the need of waiting for completion of the in-loop filter processing for a picture or an image unit. In another embodiment, two adaptive filters derive their respective adaptive filter parameters based on the same pre-in-loop video data. In yet another embodiment, a moving window is used for image-unit-based coding system incorporating in-loop filter and one or more adaptive filters. The in-loop filter and the adaptive filter are applied to a moving window of pre-in-loop video data comprising one or more sub-regions from corresponding one or more image units.

Abstract: 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 [?2D/N, (2D?1)/N) can be applied to the offset term, wherein D denotes pixel bit depth and N is a power-of-two integer. Alternatively, the constrained data range for the offset term can be [?2M,2M), wherein M is an integer.

Abstract: 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.

Abstract: A method and apparatus for texture image compression in a 3D video coding system are disclosed. Embodiments according to the present invention derive depth information related to a depth map associated with a texture image and then process the texture image based on the depth information derived. The invention can be applied to the encoder side as well as the decoder side. The encoding order or decoding order for the depth maps and the texture images can be based on block-wise interleaving or picture-wise interleaving. One aspect of the present invent is related to partitioning of the texture image based on depth information of the depth map. Another aspect of the present invention is related to motion vector or motion vector predictor processing based on the depth information.

Abstract: 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.