Grouping palette index at the end and index coding using palette size and run value

Patent metadata

Field	Value
Publication number	US-10448058-B2
Application number	US-201615158795-A
Country	US
Kind code	B2
Filing date	May 19, 2016
Priority date	May 21, 2015
Publication date	Oct 15, 2019
Grant date	Oct 15, 2019

Abstract

A device for decoding video data is configured to determine, based on first entropy encoded data in the bitstream, a set of run-related syntax element groups for a current block of a current picture of the video data; determine, based on second entropy encoded data the bitstream, a set of palette index syntax elements for the current block, the first entropy encoded data occurring in the bitstream before the second entropy encoded data, wherein: each respective run-related syntax element group of the set of run-related syntax element groups indicates a respective type of a respective run of identical palette mode type indicators and a respective length of the respective run and each respective palette index syntax element of the set of palette index syntax elements indicates an entry in a palette comprising a set of sample values; and reconstruct, based on the sample values in the palette, the current block.

First claim

What is claimed is:

1. A method of decoding video data, the method comprising:
receiving a bitstream of encoded video data;
determining, based on first entropy encoded data in the bitstream, a set of run-related syntax element groups for a current block of a current picture of the video data;
determining, based on second entropy encoded data in the bitstream, a set of palette index syntax elements for the current block, the first entropy encoded data occurring in the bitstream before the second entropy encoded data, wherein:
each respective run-related syntax element group of the set of run-related syntax element groups comprises a respective syntax element indicating a length of the respective run, and
each respective palette index syntax element of the set of palette index syntax elements indicates an entry in a palette comprising a set of sample values;

wherein determining the set of run-related syntax element groups for the current block comprises, for each respective run-related syntax element group of the set of run-related syntax element groups:
selecting, from a plurality of entropy coding contexts, a respective entropy coding context for the respective run-related syntax element group, wherein the selecting is:
not dependent on any of the palette index syntax elements, and
dependent on one or both of a position within the current block of a starting pixel of a respective run corresponding to the respective run-related syntax element group or a size of the palette, and

entropy decoding, based on the selected entropy coding context, a bin of the respective run-related syntax element group;

wherein determining the set of palette index syntax elements comprises, for each respective palette index syntax element of the set of palette index syntax elements:
obtaining, from the bitstream, data corresponding to a respective one of the palette index syntax elements; and
entropy decoding the data corresponding to the respective palette index syntax element to determine a respective entry in the palette;

reconstructing, based on the respective syntax elements indicating the respective entries in the palette and the respective syntax elements indicating the length of the respective runs, the current block; and
outputting video data comprising a decoded version of the reconstructed current block.

2. The method of claim 1 , wherein determining the set of palette index syntax elements further comprises:
for each respective palette index syntax element of the set of palette index syntax elements:
entropy decoding the data corresponding to the respective palette index syntax element to determine a binarized version of the respective palette index syntax element;
determining, based on a number of consecutive locations with the same palette index, a binarization method; and
determining the respective palette index syntax element using the determined binarization method to debinarize the binarized version of the respective palette index syntax element.

3. The method of claim 1 , wherein determining the set of palette index syntax elements further comprises:
for each respective palette index syntax element of the set of palette index syntax elements:
entropy decoding the data corresponding to the respective palette index syntax element to determine a binarized version of the respective palette index syntax element;
determining, based on a palette size, a binarization method; and
determining the respective palette index syntax element using the determined binarization method to debinarize the binarized version of the respective palette index syntax element.

4. The method of claim 1 , wherein determining the set of palette index syntax elements further comprises:
for each respective palette index syntax element of the set of palette index syntax elements:
entropy decoding the data corresponding to the respective palette index syntax element to determine a binarized version of the respective palette index syntax element;
determining, based on a palette size and a number of consecutive locations with the same palette index, a binarization method; and
determining the respective palette index syntax element using the determined binarization method to debinarize the binarized version of the respective palette index syntax element.

5. The method of claim 1 , further comprising:
receiving a flag indicating whether an index value for the set of palette index syntax elements is predictable using a list of index predictors.

6. The method of claim 1 , further comprising:
decoding a syntax element that indicates a maximum run value indicating in the set of run-related syntax element groups used for the current block; and
decoding a run value using the maximum run value as a truncation value.

7. The method of claim 1 , further comprising:
determining a first maximum palette index value;
determining a second maximum palette index value, wherein the second maximum palette index value comprises a maximum palette index value for when a run is greater than or equal to a run threshold value, and wherein the second maximum palette index value is less than the first maximum palette index value;
when a run value is greater than or equal to the run threshold value, coding an index value using truncated binary coding with a truncation value equal to the second maximum palette index value; and
when the run value is less than the run threshold value, coding the index value using truncated binary coding with a truncation value equal to the first maximum palette index value.

8. The method of claim 1 , further comprising:
decoding one or more index values for the one or more palette entries, at least one index value of the one or more index values belonging to a first region of the palette and at least one other index value of the one or more index values belonging to a second region of the palette, wherein index values of the second region are coded in a sequential scanning order according to a restriction, the restriction indicating that the index values are to appear in the second region in the sequential scanning order, wherein the first region of the palette comprises a first group of one or more sequential palette entries and the second region of the palette comprises a second group of one or more sequential palette entries that are different than the first group.

9. The method of claim 1 , further comprising;
receiving the video data at a receiver of a wireless communication device;
storing the video data on a memory of the wireless communication device; and
processing, by one or more processors, the video data stored in the memory to reconstruct the current block.

10. The method of claim 9 , wherein the wireless communication device comprises a cellular telephone, and wherein receiving the video data at the receiver comprises demodulating the video data according to a cellular communication standard.

11. A device for decoding video data, the device comprising:
a memory configured to store a bitstream of video data; and
one or more processors configured to:
determine, based on first entropy encoded data in the bitstream, a set of run-related syntax element groups for a current block of a current picture of the video data;
determine, based on second entropy encoded data in the bitstream, a set of palette index syntax elements for the current block, the first entropy encoded data occurring in the bitstream before the second entropy encoded data, wherein:
each respective run-related syntax element group of the set of run-related syntax element groups comprises a respective syntax element indicating a length of the respective run,
each respective palette index syntax el

Assignees

• Qualcomm Inc

Inventors

• Karczewicz Marta
• Zou Feng
• Seregin Vadim
• Pu Wei
• Joshi Rajan Laxman

Classifications

• H04N19/186

  the unit being a colour or a chrominance component · CPC title

• H04N19/70

  characterised by syntax aspects related to video coding, e.g. related to compression standards · CPC title

• H04N19/187

  the unit being a scalable video layer · CPC title

• H04N19/463

  by compressing encoding parameters before transmission · CPC title

• H04N19/124

  Quantisation · CPC title