Interlaced Video Coding with Flag-Based Leading Picture Order
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Solution Overview
Problem
Existing video coding systems, such as VVC, do not support interlaced video coding with leading pictures, violating constraints that require leading pictures to immediately follow intra-random access point (IRAP) pictures, which hinders efficient implementation of interlaced video coding.
Innovation Solution
Incorporation of a flag, like the sequential field flag, to allow flexible ordering of pictures in the bitstream, enabling interlaced video coding by allowing leading pictures to precede or be separated by non-leading pictures from the IRAP picture, thereby supporting interlaced video coding within VVC systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If VVC systems use the standard constraint that leading pictures must immediately follow IRAP pictures in decoding order, then the coding structure is simple and easy to implement, but interlaced video coding cannot be supported
Solution Approach 1:
The patent introduces a flag (field_seq_flag) that dynamically changes the decoding order rules based on the video type. When the flag is set to indicate interlaced video, the decoder allows non-leading pictures to appear between IRAP pictures and leading pictures, flexing the rigid constraint to adapt to interlaced coding requirements while maintaining the same basic bitstream structure
Solution Approach 2:
The patent modifies the decoding order parameter by introducing a flag that changes the sequence of picture decoding. When the flag indicates interlaced video, the decoding order allows non-leading pictures to be positioned between IRAP pictures and leading pictures, changing the standard decoding sequence to support interlaced video while keeping the overall structure similar
2Adaptability or versatility
If VVC systems allow flexible picture ordering to support interlaced video, then interlaced video coding becomes possible, but the constraint violation requires additional flag handling complexity
Solution Approach 1:
The patent segments the picture types into distinct categories (IRAP pictures, leading pictures, non-leading pictures) and uses a flag to control their relative positioning. This segmentation allows the decoder to handle different picture types with different ordering rules without requiring complete redesign of the decoding architecture
Solution Approach 2:
The flag acts as an intermediary signal that mediates between the encoder's interlaced video requirements and the decoder's standard processing logic. Instead of requiring fundamental changes to the decoder architecture, the flag provides a simple control mechanism that enables flexible picture ordering by triggering specific decoding behavior
3Productivity
If VVC systems maintain the standard picture coding order, then processing is efficient and straightforward, but leading pictures cannot be properly positioned for interlaced video
Solution Approach 1:
The patent makes the decoding process dynamic by using a flag to adaptively adjust picture positioning based on video type. For progressive video, the standard efficient decoding order is maintained. For interlaced video, the flag triggers a modified ordering that allows non-leading pictures to be positioned between IRAP and leading pictures, maintaining efficiency while adding flexibility
Data Source
AI summary
A video coding mechanism is disclosed. The mechanism includes receiving a bitstream comprising a flag and a plurality of coded pictures including an intra random access point (IRAP) picture and one or more non-leading pictures associated with the IRAP picture. When the flag is set to a first value any leading pictures associated with the IRAP picture precede, in decoding order, all non-leading pictures associated with the IRAP picture. When the flag is set to a second value a non-leading picture precedes, in decoding order, an initial leading picture associated with the IRAP picture. The IRAP picture, any leading pictures associated with the IRAP picture, and the one or more non-leading pictures associated with the IRAP picture are decoded in decoding order based on the flag.