In various embodiments, an encoding optimization application encodes a source video sequence. The encoding optimization application partitions a source video sequence associated with a media title into multiple subsequences that include a first subsequence and a second subsequence. The encoding optimization application then generates a first encoded subsequence based on the first subsequence and a first resolution. The encoding optimization application generates a second encoded subsequence based on the second subsequence and a second resolution. Notably, the second resolution is higher than the first resolution. The encoding optimization application then aggregates the first encoded subsequence and the second encoded subsequence to generate an encoded video sequence. At least a portion of the encoded video sequence is subsequently streamed to an endpoint device during a playback of the media title.

A method of rate control in coding of a video sequence to generate a compressed bit stream is provided that includes computing a sequence base quantization step size for a sequence of pictures in the video sequence, computing a picture base quantization step size for a picture in the sequence of pictures based on the sequence base quantization step size, a type of the picture, and a level of the picture in a rate control hierarchy, and coding the picture using the picture base quantization step size to generate a portion of the compressed bit stream.

Methods and apparatus for processing of video content to optimize codec bandwidth. In one embodiment, the method includes capturing panoramic imaging content (e.g., a 360° panorama), mapping the panoramic imaging content into an equi-angular cubemap (EAC) format, and splitting the EAC format into segments for transmission to maximize codec bandwidth. In one exemplary embodiment, the EAC segments are transmitted at a different frame rate than the subsequent display rate of the panoramic imaging content. For example, the mapping and frame rate may be chosen to enable the rendering of 8K, 360-degree content at 24 fps, using commodity encoder hardware and software that nominally supports 4K content at 60 fps.

An intra prediction mode encoding and decoding method, an image decoding device, and an image encoding device operate by deriving most probable modes (MPMs) from surrounding prediction units adjacent to a current prediction unit and deriving an intra prediction mode of the current prediction unit on the basis of an MPM flag indicating whether an MPM having the same prediction mode as the intra prediction mode of the current prediction unit exists among the derived MPMs.

A combined prediction mode for encoding or decoding a pixel block of a video picture is provided. When it is determined that the combined prediction mode is used, a video codec generates an intra predictor for the current block based on a selected intra-prediction mode and a merge-indexed predictor for the current block based on a selected merge candidate from a merge candidates list. The video codec then generates a final predictor for the current block based on the intra predictor and the merge-indexed predictor. The final predictor is then used to encode or decode the current block.

An encoder includes circuitry and memory. Using the memory, the circuitry performs: deriving a plurality of reference samples positioned on a first line, for intra prediction; and generating a prediction image using the plurality of reference samples. The deriving includes interpolating a value on a second line perpendicular to the first line using values of encoded pixels on the second line to generate an interpolated value, and deriving one of the plurality of reference samples by projecting the interpolated value onto the first line.

Methods and apparatus are provided for determining quantization parameter predictors from a plurality of neighboring quantization parameters. An apparatus includes an encoder for encoding image data for at least a portion of a picture using a quantization parameter predictor for a current quantization parameter to be applied to the image data. The quantization parameter predictor is determined using multiple quantization parameters from previously coded neighboring portions. A difference between the current quantization parameter and the quantization parameter predictor is encoded for signaling to a corresponding decoder.

An image encoding method can include determining an intra prediction mode of a current prediction unit; constructing a mode group including three intra prediction modes using valid intra prediction modes of left and top blocks of the current prediction unit; determining a mode group indicator and a prediction mode index of the current prediction unit; and encoding the mode group indicator and the prediction mode index, in which the mode group indicator indicates whether or not the intra prediction mode of the current prediction unit belongs to the mode group, when the mode group indicator indicates that the intra prediction mode of the current prediction unit belongs to the mode group, the prediction mode index specifies the intra prediction mode of the current prediction unit in the mode group, when the mode group indicator indicates that the intra prediction mode of the current prediction unit does not belong to the mode group, the prediction mode index specifies the intra prediction mode of the current prediction unit among intra prediction modes besides the three intra prediction modes in the mode group.

An intra prediction mode encoding and decoding method, an image decoding device, and an image encoding device operate by deriving most probable modes (MPMs) from surrounding prediction units adjacent to a current prediction unit and deriving an intra prediction mode of the current prediction unit on the basis of an MPM flag indicating whether an MPM having the same prediction mode as the intra prediction mode of the current prediction unit exists among the derived MPMs.

An apparatus for decoding video data, the apparatus comprising an entropy decoder configured to separate at least motion information, a quantization parameter and a quantized coefficient sequence from a coded bit stream by decoding the coded bit stream; an inverse quantizer/inverse transformer configured to convert the quantized coefficient sequence to a quantization block using a scan pattern, inversely quantize coefficients of the quantization block using the quantization parameter to generate a transform block, and inversely transform the transform block to generate a residual block; and a motion compensation predictor configured to generate a prediction block of a current prediction unit using a reference index and a motion vector derived from the motion information, wherein the inverse quantizer/inverse transformer inversely quantizes the coefficients of the quantization block by selecting two effective quantization parameters that are available and exist among left, upper, and previous quantization parameters according to an order of priority levels set for the left, upper, and previous quantization parameters and using an average of the two effective quantization parameters, and wherein the motion vector is decoded using a motion vector predictor which is set equal to one of an effective spatial motion vector candidate and an effective temporal motion vector candidate.