Picture Block Decoding With Special Reference Pictures for Stream Switching

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Solution Overview

Problem

Existing video streaming methods face challenges in adjusting bit rates without causing mismatches in reconstructed reference pictures, leading to degraded video quality and inefficiencies in scalable video coding, especially during stream switching.

Innovation Solution

A method for decoding and encoding picture blocks using special reference pictures (SRPs) that are not displayed but used for reconstruction, allowing flexible stream switching with minimal bit rate overhead, applicable to both decoding and encoding devices, and suitable for multi-layer video coding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If stream switching is performed at inter-coded pictures (P or B pictures), then real-time bit rate adjustment is achieved, but mismatch of reconstructed reference pictures occurs resulting in incorrect picture reconstruction

Engineering Contradiction:

Improvereal-time bit rate adjustment capabilityVSAvoidpicture reconstruction accuracy

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary action by encoding special reference pictures (SRPs) in advance at potential stream switching points. These SRPs are prepared beforehand with the reference picture data needed for future switching operations, so when switching occurs, the decoder already has the correct reference pictures available, eliminating reconstruction errors while enabling real-time bit rate adjustment.

Inventive Principle:

Principle #10Preliminary action

2Adaptability or versatility

If Random Access Points (RAP) are assigned frequently to enable prompt stream switching, then stream switching capability is improved, but substantial bit rate overhead is introduced

Engineering Contradiction:

Improvestream switching flexibilityVSAvoidbit rate overhead

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent extracts the reference picture data that would normally be embedded in frequent RAP structures and separates it into dedicated special reference picture (SRP) units. By taking out only the essential reference picture information needed for switching and storing it in SRPs, the system achieves stream switching flexibility without the substantial bit rate overhead associated with frequent full RAP assignments.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses copying by creating special reference pictures that replicate the necessary reference picture data from the original stream. These SRPs are copies of the reference pictures needed for switching, allowing the decoder to reconstruct pictures correctly after switching without needing to receive complete RAP structures, thereby reducing bit rate overhead while maintaining switching flexibility.

Inventive Principle:

Principle #26Copying

3Adaptability or versatility

If scalable video coding is used to enable real-time bit rate adjustments, then adaptability to different bandwidths is achieved, but overall compression efficiency is degraded and computational complexity increases

Engineering Contradiction:

Improvebandwidth adaptabilityVSAvoidcomputational complexity of encoder and decoder

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent employs cheap short-living objects by using lightweight special reference picture (SRP) structures that are simple to encode and decode. These SRPs are disposable in the sense that they are created on-demand at switching points rather than maintaining complex multi-layer scalable structures continuously. This approach provides bandwidth adaptability through simple stream switching while avoiding the high computational complexity of full scalable video coding.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Data Source

PatentUS12445635B2Coding and decoding methods of a picture block, corresponding devices and data stream

Publication Date: 2025.10.14 INTERDIGITAL VC HOLDINGS INC

AI summary

A method for decoding a picture block is disclosed. The decoding method comprises: decoding (10) at least one stream S_diff into decoded data and into one information for identifying a reconstructed reference picture in a decoder picture buffer; reconstructing (12) a special reference picture from at least the identified reconstructed reference picture and from the decoded data; reconstructing (16) the picture block from at least the special reference picture, wherein the at least the special reference picture is not displayed.