A method for decoding a video bitstream is disclosed. The method comprises: entropy decoding a first portion of a video bitstream, wherein first portion of video bitstream is associated with a video frame, thereby producing a first portion of decoded data; entropy decoding a second portion of video bitstream, wherein second portion of video bitstream is associated with video frame, thereby producing a second portion of decoded data, wherein entropy decoding second portion of video bitstream is independent of entropy decoding first portion of video bitstream; and reconstructing a first portion of video frame associated with video bitstream using first portion of decoded data and second portion of decoded data.

A computer implemented method for controlling a transmission of a video stream is provided. The method comprises estimating a number of bits for a group of pictures, GOP, of the video stream to be transmitted, setting a latency requirement for the transmission of the video stream, determining an average minimum video bitrate across the GOP based on the estimated number of bits and a time corresponding to a time period represented by a duration of the GOP, for video frames in the GOP setting an output bitrate for transmission of a video frame based on the latency requirement and the average minimum video bitrate, and transmitting the video frame using the output bitrate.

A computer implemented method for controlling a transmission of a video stream is provided. The method comprises estimating a number of bits for a group of pictures, GOP, of the video stream to be transmitted, setting a latency requirement for the transmission of the video stream, determining an average minimum video bitrate across the GOP based on the estimated number of bits and a time corresponding to a time period represented by a duration of the GOP, for video frames in the GOP setting an output bitrate for transmission of a video frame based on the latency requirement and the average minimum video bitrate, and transmitting the video frame using the output bitrate.

Systems and methods for controlling compression of image data by a quality controller include obtaining a desired target number of bits to be generated from compression of a current image area using a predetermined compression protocol, determining a calculated quantisation level based on the desired number of bits using a predetermined relationship between the number of bits and quantisation level, selecting a discrete quantisation level from a plurality of predetermined discrete quantisation levels based on the calculated quantisation level, determining a predicted number of bits that would result from compression of the current image area at the selected discrete quantisation level using the predetermined relationship, determining whether the predicted number of bits exceeds the desired number of bits and, if not, providing to an encoder information to enable the encoder to determine a set of compression parameters associated with the selected discrete quantisation level.

Video decoding innovations for multithreading implementations and graphics processor unit (“GPU”) implementations are described. For example, for multithreaded decoding, a decoder uses innovations in the areas of layered data structures, picture extent discovery, a picture command queue, and/or task scheduling for multithreading. Or, for a GPU implementation, a decoder uses innovations in the areas of inverse transforms, inverse quantization, fractional interpolation, intra prediction using waves, loop filtering using waves, memory usage and/or performance-adaptive loop filtering. Innovations are also described in the areas of error handling and recovery, determination of neighbor availability for operations such as context modeling and intra prediction, CABAC decoding, computation of collocated information for direct mode macroblocks in B slices, reduction of memory consumption, implementation of trick play modes, and picture dropping for quality adjustment.

Video decoding innovations for multithreading implementations and graphics processor unit (“GPU”) implementations are described. For example, for multithreaded decoding, a decoder uses innovations in the areas of layered data structures, picture extent discovery, a picture command queue, and/or task scheduling for multithreading. Or, for a GPU implementation, a decoder uses innovations in the areas of inverse transforms, inverse quantization, fractional interpolation, intra prediction using waves, loop filtering using waves, memory usage and/or performance-adaptive loop filtering. Innovations are also described in the areas of error handling and recovery, determination of neighbor availability for operations such as context modeling and intra prediction, CABAC decoding, computation of collocated information for direct mode macroblocks in B slices, reduction of memory consumption, implementation of trick play modes, and picture dropping for quality adjustment.

Video decoding innovations for multithreading implementations and graphics processor unit (“GPU”) implementations are described. For example, for multithreaded decoding, a decoder uses innovations in the areas of layered data structures, picture extent discovery, a picture command queue, and/or task scheduling for multithreading. Or, for a GPU implementation, a decoder uses innovations in the areas of inverse transforms, inverse quantization, fractional interpolation, intra prediction using waves, loop filtering using waves, memory usage and/or performance-adaptive loop filtering. Innovations are also described in the areas of error handling and recovery, determination of neighbor availability for operations such as context modeling and intra prediction, CABAC decoding, computation of collocated information for direct mode macroblocks in B slices, reduction of memory consumption, implementation of trick play modes, and picture dropping for quality adjustment.

An image decoding method and an image decoding apparatus is provided. The method comprises recovering a first motion vector corresponding to a first decoding reference picture based on the entropy decoded bit stream, calculating a second motion vector corresponding to a second decoding reference picture by scaling the first motion vector based on a first temporal distance between the current picture and the first decoding reference picture and a second temporal distance between the current picture and the second decoding reference picture, generating a prediction block relating to a current block in the current picture, based on the calculated second motion vector, generating a residual block relating to the current block through a residual data decoding process based on the entropy decoded bit stream, and recovering the current block based on the prediction block and the residual block.

An image decoding method and an image decoding apparatus is provided. The method comprises recovering a first motion vector corresponding to a first decoding reference picture based on the entropy decoded bit stream, calculating a second motion vector corresponding to a second decoding reference picture by scaling the first motion vector based on a first temporal distance between the current picture and the first decoding reference picture and a second temporal distance between the current picture and the second decoding reference picture, generating a prediction block relating to a current block in the current picture, based on the calculated second motion vector, generating a residual block relating to the current block through a residual data decoding process based on the entropy decoded bit stream, and recovering the current block based on the prediction block and the residual block.

A video encoding device includes a local decode generation unit for generating a reference image based on a result of encoding of a divided image, a compression unit for compressing the reference image to generate a compressed data, a reference image storage determination unit for determining whether to store the compressed data in a memory, and an inter-prediction unit for performing motion vector search for inter-coding based on a reference image stored in the memory. The reference image storage determination unit sets an allowable data amount used for storing the reference image for each determined area of the moving image data, and determines whether or not to store the compressed data obtained by compressing the reference image in the memory based on the allowable data amount. Inter-prediction unit sets the reference image corresponding to the compressed data stored in the memory as the search range of motion vector search.