Implicit Collocated Picture Determination in Video Compression

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Solution Overview

Problem

Current video compression systems, particularly HEVC, face inefficiencies in encoding and decoding due to the need for explicit signaling of collocated pictures, which increases bitstream overhead and complexity.

Innovation Solution

Implementing an implicit method for determining collocated pictures within the encoder and decoder, allowing them to select reference pictures from lists without explicit communication, thereby reducing the need for signaling flags like collocated_from_l0_flag and optimizing the encoding and decoding processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If explicit signaling is used to indicate collocated picture selection, then the decoder can accurately determine which reference picture to use, but the bitstream overhead increases

Engineering Contradiction:

Improveaccuracy of collocated picture determinationVSAvoidbitstream overhead

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The patent extracts and removes the explicit signaling flag (collocated From L0 flag) from the bitstream. By taking out this redundant information, the system eliminates the need for explicit communication while maintaining reliable collocated picture determination through implicit rules-based selection.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The encoder and decoder independently determine the collocated picture using the same implicit rules without requiring communication between them. Each side serves itself by applying the same determination logic, eliminating the need for signaling while maintaining synchronization.

Inventive Principle:

Principle #25Self-service

2Reliability

If explicit signaling flags are used to indicate collocated picture selection, then the decoder can correctly identify the reference picture, but the encoding and decoding complexity increases

Engineering Contradiction:

Improvecorrect identification of reference pictureVSAvoidencoding and decoding complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the collocated From L0 flag and associated signaling mechanisms from the system. This extraction simplifies the encoder and decoder by eliminating the need to process, transmit, and interpret these flags, while the correct reference picture identification is maintained through implicit determination rules.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Both encoder and decoder use the same implicit rules to independently determine the collocated picture without requiring complex signaling interactions. This self-service approach reduces the complexity of coordination between encoding and decoding sides while maintaining reliable reference picture identification.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS9300959B2Implicit determination of collocated picture for temporal prediction

Publication Date: 2016.03.29 GOOGLE TECHNOLOGY HOLDINGS LLC

AI summary

In one embodiment, a method determines a block of a current picture and a prediction type associated with the block. Also, the method determines one of a first list of reference pictures and a second list of reference pictures for the block. An encoder or a decoder selects the one of the first list of reference pictures or the second list of reference pictures implicitly without communication of information between the encoder and the decoder indicating which of the first list of reference pictures or the second list of reference pictures was selected. Then, the method sets a reference picture in the selected one of the first list of reference pictures and the second list of reference pictures as a collocated picture for the block. The selected reference picture is used in a temporal prediction process for the block.