Interlaced Video Reference List Construction for Coding Efficiency
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Solution Overview
Problem
Current encoding solutions for interlaced video data, such as those in the SVC standard, do not effectively address the need for constructing reference lists that accommodate interlaced video coding, leading to inefficiencies in encoding and decoding processes, particularly in handling bi-directionally predicted frames and interlaced field pairs.
Innovation Solution
The method involves constructing reference lists for interlaced video by ensuring that if a reference to another frame is included, both fields of that frame are referenced separately and in direct sequence, with specific rules for referencing same-type and opposite-type fields, and using different quantization parameters for top and bottom fields to improve coding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional reference list construction is used for interlaced video, then the encoding process can proceed with existing frameworks, but coding efficiency deteriorates due to inability to optimize for interlaced field pairs
Solution Approach 1:
The invention segments the reference list construction process by separately handling top fields and bottom fields. Each field type maintains its own reference list, allowing independent optimization for interlaced video coding. This segmentation enables the encoder to selectively reference appropriate fields (e.g., bottom field referencing top field of same frame) without being constrained by conventional frame-based reference lists.
Solution Approach 2:
The invention transitions from frame-based reference lists to field-based reference lists, adding a new dimension of granularity. Instead of referencing entire frames, the system references individual fields (top or bottom), enabling more precise prediction for interlaced video. This dimensional change from frame level to field level is crucial for optimizing interlaced video coding efficiency.
2Measurement precision
If bi-directional prediction is used for B frames, then prediction accuracy improves, but reference list management becomes more complex due to need to handle multiple reference frames and fields
Solution Approach 1:
The invention segments the reference list into separate lists for top fields and bottom fields. This segmentation simplifies bi-directional prediction management by allowing independent control over which fields can reference which. For example, bottom fields can reference top fields of the same frame, while top fields reference bottom fields, creating a structured approach to bi-directional prediction that reduces management complexity.
Solution Approach 2:
The invention applies local quality by allowing different reference patterns for different field types. Top fields and bottom fields have different reference capabilities and constraints. This local differentiation enables optimized prediction for each field type while maintaining overall system manageability through consistent field-based organization.
3Productivity
If quantization parameters are uniformly applied to all frames, then processing is simplified, but coding efficiency deteriorates due to inability to optimize for different temporal levels and field types
Solution Approach 1:
The invention applies local quality by assigning different quantization parameters to different field types and temporal levels. Top fields and bottom fields can have different QP values, as can fields at different temporal levels within the same frame. This localized optimization allows the encoder to adjust quantization fine-grained to match the specific requirements of each field, improving coding efficiency while maintaining manageable complexity through systematic QP assignment rules.
Data Source
AI summary
Often hierarchical bi-directionally predicted frame structures are used for encoding a video picture sequence. The frames may consist of interlacing fields. A method for encoding interlaced video, wherein inter-prediction of fields is used and reference lists are assigned to the fields for indicating reference frames or fields, comprises that, if within such reference list a reference to another frame is included, then references to both fields of the other frame are included separately in direct sequence. Further, a temporal level is assigned to each of the frames according to their display order, and for the frames of all except one temporal level the quantization parameter is higher for one type of fields than for the other type of fields.