Abstract:
In an example, aspects of this disclosure relate to a method of coding data that includes coding a sequence of bins according to a context adaptive entropy coding process. A current coding cycle used to code at least one bin of the sequence of bins includes determining a context for the bin; selecting a probability model based on the context, wherein the probability model is updated based on a value of a previous bin coded with the context and coded at least two coding cycles prior to the current coding cycle; applying the probability model to code the bin; and updating the probability model based on a value of the bin.
Abstract:
In an example, a method includes coding significance information for transform coefficients in a set of transform coefficients associated with the residual video data according to a scan order in one or more first passes. The method also includes coding a first set of one or more bins of information for the transform coefficients according to the scan order in one or more second passes, where the first set of one or more bins are coded in a first mode of a coding process. The method also includes coding a second set of one or more bins of information for the transform coefficients according to the scan order in one or more third passes, where the second set of one or more bins are coded in a second mode of the coding process.
Abstract:
At least one particular method and apparatus provide an enhanced quality low resolution image extracted from a scalable high resolution bit stream in a DCP bit stream. In various implementations, an enhancement layer is used to produce the enhanced low resolution image. The enhancement layer may include, for example, spatial-domain or frequency-domain information to be used to enhance the typical low resolution image extracted from a DCP bit stream. One specific process includes encoding a digital image into an encoded image. The encoded image is capable of being processed to provide a higher resolution decoding of the digital image and to provide a lower resolution decoding of the digital image. The process further includes encoding additional information for enhancing the lower resolution decoding to provide an enhanced lower resolution image. A complimentary signal and decoding process are also provided, as well as structures for performing the processes.
Abstract:
This disclosure describes techniques for coding video data. In particular, this disclosure describes techniques for entropy coding of residual transform coefficients generated by a video coding process. In one example, a method selects a bin 2 context for coding a bin 2 level of one or more transform coefficients in the vector according to the entropy coding process. The method further codes the bin 2 level of one or more transform coefficients in the vector according to the selected bin 2 context. Selecting the bin 2 context comprises selecting the bin 2 context for a current transform coefficient in the vector based on the bin 2 level of one or more previously coded transform coefficients in the vector.
Abstract:
In one example, a method for coding video data includes identifying a scan path for scanning significance information associated with a quantized transform coefficient. The method also includes determining a context support neighborhood for entropy coding the significance information associated with the quantized transform coefficient, wherein the context support neighborhood excludes one or more context support elements that are located in the scan path. The method also includes coding the significance information using the modified context support neighborhood.
Abstract:
In an example, aspects of this disclosure relate to a method of coding video data that includes determining a quantization parameter (QP) for coding residual video data, where the QP is indexed to a quantizer step size. The method also includes determining a quantization scaling value for scaling the quantizer step size, and applying the quantization scaling value scaling to the quantizer step size. The method also includes coding the residual video data using the scaled quantizer step size.
Abstract:
In one example, a device for coding video data includes a video coder, such as a video encoder or a video decoder, that is configured to code information indicative of whether a transform unit of the video data is square or non-square, and code data of the transform unit based at least in part on whether the transform unit is square or non-square. In this manner, the video coder may utilize non-square transform units. The video coder may be configured to use non-square transform units for certain situations, such as only for chrominance or luminance components or only when a corresponding prediction unit is non-square. The video coder may further be configured to perform an entropy coding process that selects context for coding data of the transform unit based on whether the transform unit is square or non-square.
Abstract:
In an example, aspects of this disclosure relate to a method for decoding transform coefficients in a video decoding process that includes decoding a one-dimensional array of transform coefficients, and performing a scan on the one-dimensional array of transform coefficients according to a sub-block scan order and a coefficient scan order to produce a block of transform coefficients, where the sub-block scan order comprises an order in which each sub-block of a plurality of sub-blocks within the block is scanned, and where the coefficient scan order comprises an order in which the transform coefficients corresponding to each sub-block of the plurality of sub-blocks are scanned.
Abstract:
A video decoder converts a block-based LSC indicator into a scan-based LSC indicator. The block-based LSC indicator indicates coordinates of a last significant coefficient of a block of transform coefficients according to a scanning order. The scan-based LSC indicator indicates an ordinal position of the LSC according to the scanning order. The video decoder may decode, based on the scan-based LSC indicator, a significance map for the block.
Abstract:
In one example, an apparatus is disclosed for coding coefficients associated with a block of video data during a video coding process, wherein the apparatus includes a video coder configured to code x- and y-coordinates that indicate a position of a last non-zero coefficient within the block according to a scanning order associated with the block when the scanning order comprises a first scanning order, and code interchanged x- and y-coordinates that indicate the position of the last non-zero coefficient within the block according to the scanning order when the scanning order comprises a second scanning order, wherein the second scanning order is different than the first scanning order.