Palette Map Construction for Video Signal Restoration
Solution Overview
Problem
Current video compression techniques face challenges in efficiently encoding and decoding high-resolution, high-quality video signals, particularly for 3D video content, due to increased data size and transmission/storage costs.
Innovation Solution
A method and apparatus for constructing a palette map and deriving a palette index in a block encoded/decoded in palette mode, using scanning orders like horizontal or vertical traverse scans, and employing index or copy modes to restore samples, with an escape mode for out-of-range values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-resolution and high-quality video signals are used, then image quality is improved, but data size increases
Solution Approach 1:
The patent applies parameter changes by transforming the video signal representation from direct pixel values to palette indices. The video signal is converted using a palette map where each pixel is represented by an index pointing to a color entry in the palette, rather than storing full color values. This parameter transformation significantly reduces the number of bits required to represent each pixel while maintaining visual quality, directly resolving the contradiction between image quality and data size.
2Quantity of substance
If video data size increases, then transmission and storage costs increase
Solution Approach 1:
The patent reduces video data size by changing the parameter representation from full-color pixel values to compact palette indices. Each pixel is encoded as an index (typically requiring fewer bits) that references a color definition in the palette map. This parameter transformation directly reduces the quantity of data that needs to be transmitted and stored, thereby reducing transmission and storage costs as indicated in the patent.
3Productivity
If palette mode is used for encoding, then compression efficiency is improved, but decoding complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-defining the palette map before encoding the actual video data. The palette map, which contains all the color definitions and their corresponding indices, is constructed and transmitted first. During decoding, the palette map is reconstructed first, and then the video data is simply decoded by looking up indices in this pre-established palette map. This preliminary preparation simplifies the decoding process compared to generating the palette dynamically, thereby reducing decoding complexity while maintaining compression efficiency.
Data Source
AI summary
Provided is a method for decoding a video signal. Such a method may include constructing a palette map for a current block encoded in a plate mode, the palette map comprises at least one palette entry and a map index that for identifying the palette entry, deriving a palette index according to a predetermined scan order of the current block on a sample-by-sample basis, and reconstructing each sample of the current block by using a palette entry having a map index of the same value as the derived palette index from the palette map.