Abstract:
Methods for coding syntax related to palette coding generated in a video coding system are disclosed. According to one embodiment, the current block size checked against the pre-defined block size. If the current block size is larger than the pre-defined block size, a current coding mode is selected from a coding group excluding a palette coding mode. If the current block size is smaller than or equal to the pre-defined block size, the current coding mode is selected from a coding group including the palette coding mode. In another embodiment, if the current block size is greater than a maximum transform size, a current coding mode is selected from a coding group excluding a palette coding mode. If the current block size is smaller than or equal to the maximum transform size, the current coding mode is selected from a coding group including the palette coding mode.
Abstract:
A method of video coding using the palette coding mode with reduced complexity by sharing context(s) between context-based entropy coding of syntax element for the last run type mode and context-based entropy coding of syntax element for the run type mode is disclosed. A method with reduced complexity for binarization of the syntax element associated with the number of palette indices of the current block is disclosed, where Rice parameter is derived for the number of palette indices without the need for a division or table lookup operation. In another method, the syntax element to specify whether transpose process is applied to associated palette indices of the current block is signalled in the bitstream for the current block in a location after the syntax element to specify a last run type mode for the current block.
Abstract:
A method of video coding with reduced implementation cost by reusing transform coefficient buffer palette for palette coding is disclosed. If the current prediction mode is an Intra prediction mode or the Inter prediction mode, information related to transform coefficients for prediction residual of the current block resulted from Intra prediction or Inter prediction is stored in the transform coefficient buffer. If the current prediction mode is the palette coding mode, information related to palette data associated with the current block is stored in the transform coefficient buffer. The current block is then encoded or decoded based on the information related to the transform coefficients if the current block is coded in the Intra prediction mode or the Inter prediction mode, or the information related to the palette data stored in the transform coefficient buffer if the current prediction mode is the palette coding mode.
Abstract:
A method of video coding with reduced implementation cost by reusing transform coefficient buffer palette for palette coding is disclosed. If the current prediction mode is an Intra prediction mode or the Inter prediction mode, information related to transform coefficients for prediction residual of the current block resulted from Intra prediction or Inter prediction is stored in the transform coefficient buffer. If the current prediction mode is the palette coding mode, information related to palette data associated with the current block is stored in the transform coefficient buffer. The current block is then encoded or decoded based on the information related to the transform coefficients if the current block is coded in the Intra prediction mode or the Inter prediction mode, or the information related to the palette data stored in the transform coefficient buffer if the current prediction mode is the palette coding mode.
Abstract:
Methods for coding a block of video data using palette coding in a video coding are disclosed. According to one embodiment, the palette transpose flag is signaled conditionally depending on the maximum index value or the palette size. If the maximum index value or the palette size is equal to or greater than a threshold size, the palette transpose flag is signaled at an encoder side or parsed at a decoder side. Otherwise, the palette transpose flag is not signaled or parsed. In another embodiment, the last palette and the last palette size are updated by the current palette with the current palette size conditionally. For example, updating the last palette and the last palette size by the current palette with the current palette size is skipped if the current coding unit is coded using a pulse-coded modulation (PCM) mode or the current palette size is zero.
Abstract:
A method of video coding using palette coding mode for color video in a non-444 color format is disclosed. The non-444 video data can be converted to the 444 format so that the palette designed for the 444 format can be used for the non-444 video data. For the 4:2:0 color format, each chroma sample collocated with corresponding quad luma samples is padded with three chroma samples to form converted quad chroma samples. For the 4:2:0 color format, if a current pixel does not belong to the color palette, one or more escape values are signaled for the current pixel and the escape value associated with the chroma sample of the current pixel for each color component is not signaled for three of the quad chroma sample locations collocated with corresponding quad luma samples.
Abstract:
An apparatus and method of coding a palette table using a palette predictor list operate by receiving input data associated with a current block in a picture, receiving a current palette for a current block in the picture, and receiving the palette predictor list for the current palette. For a current position of the palette predictor list, the operations determine a current palette predictor run, wherein a distance between the current position of the palette predictor list and a next position of a next palette entry of the palette predictor list corresponds to the current palette predictor run. Further, the operation constrains a syntax element representing the current palette predictor run to a range of values to cause the next palette entry of the palette predictor list to be within the palette predictor list, and signal or parse the syntax element in a bitstream for the current block.
Abstract:
Methods to overcome issues associated with predictors being an Escape pixel in palette coding using a copy mode are disclosed. According to one embodiment, if the predictor for a copy-above mode is an Escape pixel, the pixel value of the current Escape pixel is transmitted so that it can be reconstructed using the transmitted pixel value. In another embodiment, restriction is applied to the encoder side, where in the copy-above mode, the copy-above run is terminated or the copy-above mode is not selected for the current pixel whenever an above pixel located above a current pixel is an Escape pixel. In yet another embodiment, directly copying the Escape value is used, where both the Escape index and Escape value, or the reconstructed pixel value of the predictor is directly copied to reconstruct a current pixel when the predictor is an Escape pixel.
Abstract:
In a palette prediction that includes a copy-above mode for predicting one or more first pixels based on one or more above pixels located above said one or more first pixels correspondingly, a method of palette mode coding using palette prediction for a picture includes receiving input data associated with a current block and determining a current coding mode for one or more current pixels. If the current coding mode corresponds to the copy-above mode, then the method identifies one or more above pixels located above said one or more current pixels correspondingly, wherein said one or more above pixels are restricted to be non-Escape pixels. The method further encodes the one or more current pixels by using said one or more above pixels as predictors.
Abstract:
A simplified syntax signalling for the number of palette indices is disclosed, where the syntax element corresponding to the total number of palette indices minus one is signalled and the palette indices are associated with the copy-index modes in the current block. In another embodiment, a syntax corresponding to the number of palette indices minus 1 is signalled, where the palette indices are associated with the copy-index modes in the current block. According to this embodiment, the syntax is constrained to a range from 0 to block size minus 1. In yet another embodiment, conformance constraint is imposed on the palette predictor run. For a current position of the palette predictor list, a syntax element corresponding to a current palette predictor run is parsed from the input bitstream and the syntax element is constrained to a range of values access valid entries in the palette predictor.