A multimedia file and methods of generating, distributing and using the multimedia file are described. Multimedia files in accordance with embodiments of the present invention can contain multiple video tracks, multiple audio tracks, multiple subtitle tracks, a complete index that can be used to locate each data chunk in each of these tracks and an abridged index that can enable the location of a subset of the data chunks in each track, data that can be used to generate a menu interface to access the contents of the file and ‘meta data’ concerning the contents of the file. Multimedia files in accordance with several embodiments of the present invention also include references to video tracks, audio tracks, subtitle tracks and ‘meta data’ external to the file. One embodiment of a multimedia file in accordance with the present invention includes a series of encoded video frames, a first index that includes information indicative of the location within the file and characteristics of each encoded video frame and a separate second index that includes information indicative of the location within the file of a subset of the encoded video frames.

According to the disclosure of the present document, a residual sample can be derived by applying adaptive color transform (ACT) with respect to a current block on the basis of ACT-associated information, wherein the residual sample is derived by being clipped on the basis of a clipping boundary, wherein the clipping boundary is determined on the basis of a bit depth.

An apparatus for decoding video data and including an entropy decoder configured to separate at least an intra mode index, 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, 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; an intra predictor configured to restore an intra prediction mode of a current prediction unit using the intra mode index and generate a prediction block of the current prediction unit according to the intra prediction mode when the coded bit stream is coded in the intra prediction mode; 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 when the coded bit stream is coded in an inter prediction mode. Further, the motion vector is decoded using a motion vector predictor which is set equal to one of an effective spatial merge candidate and a temporal merge candidate, and a motion vector of the temporal merge candidate is a motion vector of a temporal merge candidate within a temporal merge candidate picture, and the quantization parameter is encoded using an average of two effective quantization parameters among a left quantization parameter, an upper quantization parameter and a previous quantization parameter of a current coding unit, When the quantized block is larger than a predetermined size, the quantized coefficient sequence is inversely scanned in a unit of sub-block using a scan pattern and a plurality of sub-blocks are inversely scanned using a scan pattern, and the scan pattern for inversely scanning the plurality of sub-blocks is the same as the scan pattern for inversely scanning the quantized coefficients sequence. Also, the scan pattern for inversely scanning the quantized coefficients is determined according to the intra prediction mode and a size of a transform unit when the coded bit stream is coded in the intra prediction mode.

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 video quality estimation apparatus used for an encoded video, to estimate a video quality value being a value quantifying a video quality being quality of the video felt by a user when viewing and listening to the video. The apparatus includes a maximum value calculator to calculate a maximum value of the video quality value from a resolution of the video and a frame rate of the video, and a video quality calculator to calculate an estimated video quality value corresponding to an encoding bit rate having been input, based on a predetermined relationship between the encoding bit rate of the video and the video quality value. The predetermined relationship is a relationship in which the video quality value increases while the encoding bit rate increases, and the video quality value converges on the maximum value calculated by the maximum value calculator.

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° content at 24 fps, using commodity encoder hardware and software that nominally supports 4K content at 60 fps.

A method and apparatus for video encoding and decoding with prediction offset in a video coding system are disclosed. A prediction offset for a current block is derived from a reconstructed residual signal of one or more coded blocks. At the encoder side, a residual signal for the current block is calculated by subtracting a prediction signal and the prediction offset from an original signal of the current block, and the residual signal is encoded to generate an encoded bitstream. At the decoder side, a residual signal for the current block is obtained from input data, a reconstructed signal for the current block is calculated by adding a prediction signal and the prediction offset to the residual signal, and the current block is decoded using the reconstructed signal.

An image processing method and device include parsing a code stream to obtain a first quantization parameter of a current image area in an original resolution coding scheme, a second quantization parameter of the current image area in a downsampling coding scheme, a coding scheme of a current image block in the current image area, a quantization coefficient of the current image block, and a prediction signal of the current image block, determining a quantization parameter of the current image block according to the coding scheme, and reconstructing the current image block based on the quantization parameter, the quantization coefficient, and the prediction signal to obtain a current reconstructed image block.

A multimedia file and methods of generating, distributing and using the multimedia file are described. Multimedia files in accordance with embodiments of the present invention can contain multiple video tracks, multiple audio tracks, multiple subtitle tracks, a complete index that can be used to locate each data chunk in each of these tracks and an abridged index that can enable the location of a subset of the data chunks in each track, data that can be used to generate a menu interface to access the contents of the file and ‘meta data’ concerning the contents of the file. Multimedia files in accordance with several embodiments of the present invention also include references to video tracks, audio tracks, subtitle tracks and ‘meta data’ external to the file. One embodiment of a multimedia file in accordance with the present invention includes a series of encoded video frames, a first index that includes information indicative of the location within the file and characteristics of each encoded video frame and a separate second index that includes information indicative of the location within the file of a subset of the encoded video frames.

Techniques are provided for temporal control of a spatially adaptive tone mapping (SATM). The techniques can be applied to a sequence of video images (e.g., high dynamic range (HDR) video). The temporal control may reduce flickering and other undesirable artifacts that can be introduced by SATM processing. An example system includes an SATM circuit configured to perform SATM on sequential image frames of an input video, to reduce the dynamic range of the video to a level suitable for display on a conventional (lower dynamic range) device. The SATM operation is based on frame parameters. The system also includes a parameter smoothing circuit configured to apply a smoothing filter to the parameters used on the current frame to generate a new set of parameters for use by the SATM circuit on the next frame. The system also includes an adaptation circuit to compress variation of SATM exposure correction over time.