Reference Picture Selection Feedback Loop for Video Coding Efficiency

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Solution Overview

Problem

Existing video coding technologies face challenges in selecting optimal reference pictures for encoding and decoding, leading to potential errors and reduced coding efficiency due to limitations in communication between video encoders and decoders, particularly in real-time applications like video conferencing and live streaming.

Innovation Solution

A method where a video decoder communicates information to a video encoder to select reference pictures from a buffer, ensuring high certainty that the selected pictures are available for decoding, allowing the encoder to choose from a plurality of candidate reference pictures for inter-prediction, thereby enhancing coding efficiency and reducing error propagation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the video encoder selects reference pictures from a limited set or uses fixed reference picture selection, then the device complexity and communication overhead are reduced, but the coding efficiency and adaptability to real-time conditions deteriorate

Engineering Contradiction:
Improvecoding efficiencyVSAvoidreference picture selection complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent implements a feedback mechanism where the video decoder provides information about acknowledged reference pictures to the video encoder. This feedback loop enables the encoder to adapt its reference picture selection based on actual decoder capabilities and buffer status, resolving the contradiction between coding efficiency and system complexity by using targeted information exchange rather than full-state synchronization

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The reference picture selection process is made dynamic and adaptive rather than fixed. The encoder adjusts its reference picture choices in real-time based on feedback about which pictures are available and acknowledged at the decoder, allowing the system to optimize coding efficiency for each specific moment while maintaining manageable complexity through conditional logic

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If the video encoder and decoder use different reference picture buffers or have different reference picture availability, then the flexibility and adaptability of the system improve, but the reliability and error propagation increase

Engineering Contradiction:
Improvereference picture buffer flexibilityVSAvoidreference picture availability reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The feedback mechanism directly addresses reliability by having the decoder explicitly acknowledge which reference pictures are available in its buffer. This allows the encoder to verify reference picture availability before using them, preventing errors from mismatched references while maintaining the flexibility to adapt to different buffer states

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs beforehand cushioning by having the decoder acknowledge reference pictures in advance before the encoder uses them. This preventive check ensures that referenced pictures are actually available at the decoder, cushioning against potential errors and synchronization issues that would arise from using different reference sets

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Productivity

If the video encoder uses real-time communication with the video decoder to select reference pictures, then the coding efficiency and error reduction improve, but the loss of time and bandwidth usage increase

Engineering Contradiction:
Improvecoding efficiencyVSAvoidcommunication time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The system applies partial action by having the decoder communicate only the essential information about acknowledged reference pictures rather than complete buffer states. This selective feedback reduces communication overhead and time loss while maintaining sufficient information for the encoder to make optimal reference picture selections

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The feedback mechanism enables efficient real-time adaptation with minimal communication by exchanging only the necessary reference picture availability information. This targeted feedback allows the encoder to optimize coding efficiency without requiring extensive communication protocols, thus minimizing time and bandwidth losses

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3078193B1Reference picture selection
Publication Date: 2018.10.03 QUALCOMM INC
  • EP3078193B1 patent drawingFigure 1
  • EP3078193B1 patent drawingFigure 2
  • EP3078193B1 patent drawingFigure 3

AI summary

Techniques are described where a device that includes a video decoder outputs information identifying a picture to a device that includes a video encoder. The video encoder may determine pictures that could have been used to inter-prediction encode the identified picture and/or pictures following the identified picture in coding order. The video encoder may inter-prediction encode a current picture based on one or more of the determined pictures and/or the identified picture.