CN-114556933-B - Palette escape coding based image or video coding

CN114556933BCN 114556933 BCN114556933 BCN 114556933BCN-114556933-B

Abstract

According to the disclosure of this document, information used in palette coding mode can be effectively signaled. For example, information related to the availability of palette modes may be signaled and information related to quantization escape values may be signaled based on the information related to the availability of palette modes. In addition, as a quantization parameter of the quantization escape value, minimum quantization parameter information related to the transform skip mode may be signaled. Accordingly, information required for palette mode encoding can be efficiently signaled, and escape encoding efficiency in palette mode can be improved.

Inventors

ZHAO JIE
JIN SHENGHUAN
S. Paluli

Assignees

LG电子株式会社
LG电子株式会社

Dates

Publication Date: 20260421
Application Date: 20200826
Priority Date: 20200826

Claims (12)

1. An image decoding method performed by a decoding apparatus, the image decoding method comprising the steps of: Obtaining image information including information on whether a palette mode is enabled from a bitstream; deriving a quantization escape value for a current block based on the information on whether the palette mode is enabled; Deriving an escape value for the current block based on the quantization escape value and quantization parameter, and A reconstructed sample is generated based on the escape value, Wherein the image information includes minimum quantization parameter information in a transform skip mode, Wherein the quantization parameter is derived based on the minimum quantization parameter information in the transform skip mode, Wherein the range of quantized escape values is determined based on the bit depth bitDepth, an Wherein the quantization escape value is in the range of 0 to (1 < < BitDepth) -1.
2. The image decoding method of claim 1, wherein the quantization parameter has a value greater than or equal to a minimum quantization parameter value derived from the minimum quantization parameter information in the transform skip mode.
3. The image decoding method of claim 1, wherein the quantization escape value is included in the image information for the current block including at least one escape coded sample.
4. The image decoding method of claim 1, wherein the image information comprises a sequence parameter set SPS, Wherein the SPS includes the minimum quantization parameter information in the transform skip mode.
5. The image decoding method of claim 1, wherein the image information includes palette size information regarding a maximum index of a palette table, Wherein the palette size information is a preset value or is determined based on the size of the coding unit.
6. The image decoding method according to claim 1, the method further comprising the steps of: Configuring a palette table based on the palette entry information; Configuring a palette index map for the current block based on palette index information; deriving sample values for palette entries in the palette table based on the palette index map, and Generating the reconstructed samples based on the palette index map and sample values of the palette entries, Wherein the image information includes the palette entry information and the palette index information.
7. An image encoding method performed by an encoding apparatus, the image encoding method comprising the steps of: determining whether palette mode is enabled for the current block; Deriving an escape value for the current block based on whether the palette mode is enabled; deriving a quantization escape value based on the escape value and the quantization parameter, and Encoding image information including information on whether the palette mode is enabled or not and information on the quantization escape value, Wherein the image information includes minimum quantization parameter information in a transform skip mode, and Wherein the quantization parameter is derived based on the minimum quantization parameter information in the transform skip mode, Wherein the range of quantized escape values is determined based on the bit depth bitDepth, an Wherein the quantization escape value is in the range of 0 to (1 < < BitDepth) -1.
8. The image encoding method of claim 7, wherein the quantization parameter has a value greater than or equal to a minimum quantization parameter value derived from the minimum quantization parameter information in the transform skip mode.
9. The image encoding method of claim 7, wherein the quantization escape value is included in the image information for the current block including at least one escape encoded sample.
10. The image encoding method of claim 7, wherein the image information includes a sequence parameter set SPS, Wherein the SPS includes the minimum quantization parameter information in the transform skip mode.
11. The image encoding method of claim 7, wherein the image information includes palette size information regarding a maximum index of a palette table, Wherein the palette size information is a preset value or is determined based on the size of the coding unit.
12. The image encoding method according to claim 7, the method further comprising the steps of: generating palette entry information based on sample values of the current block; generating palette index information of the current block based on the palette entry information, and The image information including the palette entry information and the palette index information is encoded.

Description

Palette escape coding based image or video coding Technical Field The present disclosure relates to video or image coding, and for example to palette-based escape coded image or video coding techniques. Background Recently, there is an increasing demand for high resolution, high quality images/video such as 4K or 8K Ultra High Definition (UHD) images/video in various fields. As image/video resolution or quality becomes higher, relatively more information or bits are transmitted than with conventional image/video data. Therefore, if image/video data is transmitted via a medium such as an existing wired/wireless broadband line or stored in a conventional storage medium, the cost of transmission and storage is liable to increase. In addition, there is an increasing interest and demand for Virtual Reality (VR) and Artificial Reality (AR) content, as well as immersive media such as holograms, and broadcasting of images/videos (e.g., game images/videos) that exhibit different image/video characteristics from actual images/videos. Therefore, highly efficient image/video compression techniques are needed to efficiently compress and transmit, store or play high resolution, high quality images/videos exhibiting various characteristics as described above. In addition, a palette mode encoding technique that improves the encoding efficiency of screen content such as computer-generated video that contains a large amount of text and graphics is also discussed. In order to efficiently apply the technique, a method for encoding and signaling related information is required. Disclosure of Invention Technical purpose It is an object of the present disclosure to provide a method and apparatus for improving video/image coding efficiency. It is another object of the present disclosure to provide a method and apparatus for improving efficiency of palette mode coding. It is a further object of the present disclosure to provide methods and apparatus for efficiently configuring and signaling various types of information used in palette mode coding. It is a further object of the present disclosure to provide methods and apparatus for efficiently applying escape coding in palette mode. Technical proposal According to the embodiments of the present disclosure, information used in a palette coding mode can be effectively signaled. For example, information on whether the palette mode is enabled may be signaled through a Sequence Parameter Set (SPS), and information on an escape value of quantization may be signaled through a palette coding syntax based on the information on whether the palette mode is enabled. In addition, quantization parameter information for the quantization escape value may be signaled based on information regarding whether the palette mode is enabled. In addition, the quantization parameter information for the quantization escape value is based on minimum quantization parameter information in a transform skip mode for signaling in SPS. According to embodiments of the present disclosure, a quantization parameter for a quantization escape value may be derived based on minimum quantization parameter information for a transform skip mode to derive an escape value for a current block including at least one escape encoding sample. According to embodiments of the present disclosure, the range of quantization escape values in palette mode may be limited based on bit depth. For example, the range of quantization escape values may have values between 0 and (1 < < BitDepth) -1. According to embodiments of the present disclosure, entry size information may be defined in a palette table and may be signaled by a Sequence Parameter Set (SPS). According to an embodiment of the present disclosure, there is provided a video/image decoding method performed by a decoding apparatus. The video/image decoding method may include the method disclosed in the embodiments of the present disclosure. According to an embodiment of the present disclosure, a decoding apparatus for performing video/image decoding is provided. The decoding apparatus may perform the methods disclosed in the embodiments of the present disclosure. According to an embodiment of the present disclosure, there is provided a video/image encoding method performed by an encoding apparatus. The video/image encoding method may include the method disclosed in the embodiments of the present disclosure. According to an embodiment of the present disclosure, there is provided an encoding apparatus for performing video/image encoding. The encoding apparatus may perform the methods disclosed in the embodiments of the present disclosure. According to an embodiment of the present disclosure, there is provided a computer readable digital storage medium storing encoded video/image information generated according to a video/image encoding method disclosed in at least one of the embodiments of the present disclosure. According to an embodiment of the present disclosure, there is provided a c