Disclosed is a method of encoding a video sequence according to a first set of encoding parameters is presented, including redimensioning the video sequence, generating encoding data of the redimensioned video sequence according to a second set of encoding parameters, determining first encoding data of the video sequence by respective scale transposition of encoded data generated for the redimensioned video sequence, determining, for at least one encoding block of an image of the video sequence, respective pixel residuals from predictive coding data obtained by encoding the redimensioned video sequence applying a block transformation to the pixel residuals determined, and inserting the transformed pixel residuals and the first encoding data into a binary encoding stream of the video sequence.

Systems, methods and computer readable mediums are presented for encoding a stream of input video frames, in which the input video frames are down sampled and the down sampled frames are encoded in a first encoding pass to generate a set of first pass coded frames forming a single first pass I frame and a plurality of first pass P frames formed into first pass sub-groups of pictures (SUB-GOPs). First pass encoding statistics are generated for individual first pass SUB-GOPs, and the statistics are used to encode the input video frames in a second encoding pass to generate a set of second pass coded frames.

Systems, methods and computer readable mediums are presented for encoding a stream of input video frames, in which the input video frames are down sampled and the down sampled frames are encoded in a first encoding pass to generate a set of first pass coded frames forming a single first pass I frame and a plurality of first pass P frames formed into first pass sub-groups of pictures (SUB-GOPs). First pass encoding statistics are generated for individual first pass SUB-GOPs, and the statistics are used to encode the input video frames in a second encoding pass to generate a set of second pass coded frames.

Embodiments feature families of rate allocation and rate control methods that utilize advanced processing of past and future frame/field picture statistics and are designed to operate with one or more coding passes. At least two method families include: a family of methods for a rate allocation with picture look-ahead; and a family of methods for average bit rate (ABR) control methods. At least two other methods for each method family are described. For the first family of methods, some methods may involve intra rate control. For the second family of methods, some methods may involve high complexity ABR control and/or low complexity ABR control. These and other embodiments can involve any of the following: spatial coding parameter adaptation, coding prediction, complexity processing, complexity estimation, complexity filtering, bit rate considerations, quality considerations, coding parameter allocation, and/or hierarchical prediction structures, among others.

Embodiments feature families of rate allocation and rate control methods that utilize advanced processing of past and future frame/field picture statistics and are designed to operate with one or more coding passes. At least two method families include: a family of methods for a rate allocation with picture look-ahead; and a family of methods for average bit rate (ABR) control methods. At least two other methods for each method family are described. For the first family of methods, some methods may involve intra rate control. For the second family of methods, some methods may involve high complexity ABR control and/or low complexity ABR control. These and other embodiments can involve any of the following: spatial coding parameter adaptation, coding prediction, complexity processing, complexity estimation, complexity filtering, bit rate considerations, quality considerations, coding parameter allocation, and/or hierarchical prediction structures, among others.

A method is provided to better detect a scene change to provide a prediction to an encoder to enable more efficient encoding. The method uses a Motion Compensated Temporal Filter (MCTF) that provides motion estimation and is located prior to an encoder. The MCTF provides a Motion Compensated Residual (MCR) used to detect the scene change transition. When a scene is relatively stable, the MCR score is also relatively stable. However, when a scene transition is in process, the MCR score behavior changes, Algorithmically, the MCR score is used by comparing the sliding mean of the MCR score to the sliding median. This comparison highlights the transition points. In the case of a scene cut, the MCR score exhibits a distinct spike. In the case of a fade or dissolve, the MCR score exhibits a transitional period of degradation followed by recovery. By implementing the above detection using the MCR, the location of the I-pictures in the downstream encoding process can be accurately determined for the encoder.

A method is provided to better detect a scene change to provide a prediction to an encoder to enable more efficient encoding. The method uses a Motion Compensated Temporal Filter (MCTF) that provides motion estimation and is located prior to an encoder. The MCTF provides a Motion Compensated Residual (MCR) used to detect the scene change transition. When a scene is relatively stable, the MCR score is also relatively stable. However, when a scene transition is in process, the MCR score behavior changes, Algorithmically, the MCR score is used by comparing the sliding mean of the MCR score to the sliding median. This comparison highlights the transition points. In the case of a scene cut, the MCR score exhibits a distinct spike. In the case of a fade or dissolve, the MCR score exhibits a transitional period of degradation followed by recovery. By implementing the above detection using the MCR, the location of the I-pictures in the downstream encoding process can be accurately determined for the encoder.

An image decoding method according to the present invention can comprise the steps of: deriving first reference samples located at the upper end and on the left side of a current block; deriving second reference samples located on the right side and at the lower end of the current block; and acquiring a prediction sample for the current block on the basis of the first reference samples and the second reference samples, wherein the second reference samples can be derived on the basis of the first reference samples and temporary prediction samples generated by performing temporary intra prediction on the current block on the basis of a temporary intra prediction mode.

An image decoder includes a processor and a memory. The memory includes instructions configured to cause the processor to perform operations. The operations receive an encoded image, perform a first decoding of the encoded image to generate a first decoded image, store the first decoded image in the memory, process the first decoded image for displaying, perform a second decoding of the first decoded image and generate a second decoded image, and process the second decoded image for displaying.

An image decoder includes a processor and a memory. The memory includes instructions configured to cause the processor to perform operations. The operations receive an encoded image, perform a first decoding of the encoded image to generate a first decoded image, store the first decoded image in the memory, process the first decoded image for displaying, perform a second decoding of the first decoded image and generate a second decoded image, and process the second decoded image for displaying.