Interlaced Video Coding Using Flag-Controlled IRAP Picture Ordering
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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
A flag, such as a sequential field flag, is introduced in the bitstream to allow leading pictures to precede or be positioned between IRAP and non-leading pictures, enabling interlaced video coding in VVC systems by adjusting decoding and encoding orders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If VVC systems enforce the constraint that leading pictures must immediately follow IRAP pictures, then decoding order is simplified and system reliability is improved, but interlaced video coding capability is lost
Solution Approach 1:
The patent introduces a dynamic flag mechanism (field_seq_flag) that allows the system to switch between two different decoding order configurations. When the flag is set to false, leading pictures immediately follow IRAP pictures (standard VVC mode). When the flag is set to true, non-leading pictures can be positioned between IRAP pictures and leading pictures (interlaced mode). This dynamic adaptability resolves the contradiction by allowing the system to maintain reliability through standardized operation while gaining versatility when needed.
Solution Approach 2:
The patent changes the parameter of picture decoding order by introducing a control flag that modifies the sequence constraints. The flag enables the system to alter the positional relationship between IRAP pictures, non-leading pictures, and leading pictures. This parameter change allows interlaced video coding to be supported without breaking the fundamental VVC framework, thus resolving the contradiction between system reliability and coding versatility.
2Adaptability or versatility
If VVC systems support interlaced video coding with non-leading pictures positioned between IRAP and leading pictures, then interlaced video coding capability is improved, but decoding complexity and device complexity increase
Solution Approach 1:
The dynamic flag mechanism allows the decoder to adapt its behavior based on the flag value without requiring fundamentally different decoding architectures. When the flag indicates interlaced mode, the decoder simply adjusts the picture insertion logic to place non-leading pictures in the appropriate position. This dynamic approach adds minimal complexity compared to implementing entirely separate decoding paths for different video types.
Solution Approach 2:
The patent creates a universal decoding framework that handles both standard VVC sequences and interlaced video sequences through a single codebase. The flag-based mechanism allows the same decoder to operate in multiple modes, avoiding the need for separate specialized decoders. This multi-functionality reduces overall system complexity while maintaining interlaced video coding capability.
3Adaptability or versatility
If leading pictures are positioned after non-leading pictures in decoding order, then interlaced video coding is enabled, but the constraint violation increases system complexity
Solution Approach 1:
The patent uses a simple binary flag parameter to control the decoding order configuration. This parameter change approach allows the system to switch between standard and interlaced modes without complex reconfiguration. The flag encapsulates the entire mode difference, making the system adaptable while keeping the implementation simple and manageable.
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.