Interlace Frame Coding Mode Decision via Intensity Fluctuation Analysis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing video compression techniques for interlaced video frames often inaccurately determine whether to use field coding or frame coding, leading to suboptimal rate-distortion performance due to reliance on variance in sample values alone, which can misclassify blocks with strong vertical intensity fluctuations and fail to effectively alleviate jagged artifacts.
Innovation Solution
A method that analyzes interlaced video frames by calculating vertical intensity fluctuation ratios between neighboring and alternating lines, comparing these ratios with thresholds, and considering horizontal intensity fluctuations to accurately classify blocks as interlace effect or non-interlace effect blocks, thereby determining the appropriate frame-level coding mode for efficient compression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If field coding is used for interlaced video frames with motion, then jagged artifacts are reduced, but encoding complexity increases due to separate field processing
Solution Approach 1:
The patent applies local quality by allowing different macroblocks within the same interlaced frame to use different coding modes (field coding or frame coding) based on local motion characteristics. Each macroblock is independently analyzed for interlace effects, and the coding mode is selected locally rather than applying a uniform mode to the entire frame, thus reducing artifacts in high-motion regions while maintaining efficiency in low-motion regions.
2Reliability
If two-pass encoding algorithms are used to determine frame or field coding, then rate-distortion performance is improved, but encoding time increases significantly
Solution Approach 1:
The patent performs preliminary analysis of interlace effects in each macroblock before the main encoding process. By pre-classifying macroblocks as having strong or weak interlace effects based on vertical intensity fluctuation measurements, the encoder can make informed coding mode decisions without requiring a separate two-pass encoding process, thus achieving good rate-distortion performance while maintaining single-pass encoding efficiency.
3Manufacturing precision
If frame coding is used for interlaced video frames, then image detail in stationary regions is preserved, but jagged artifacts appear in high-motion regions
Solution Approach 1:
The patent implements dynamic coding mode selection where the encoding approach (frame coding or field coding) is adaptively changed based on the motion characteristics of each macroblock. The system dynamically measures vertical intensity fluctuations and classifies macroblocks in real-time, switching between coding modes as needed rather than using a static mode for the entire frame, thus preserving image detail in stationary regions while reducing artifacts in motion regions.
4Productivity
If one-pass encoding with simple variance-based motion detection is used, then encoding speed is maintained, but coding mode decisions become inaccurate
Solution Approach 1:
The patent changes the measurement parameter from simple variance-based motion detection to vertical intensity fluctuation analysis. By measuring the fluctuation of vertical intensity values across lines within each macroblock and comparing alternating lines, the system achieves more accurate detection of interlace effects caused by motion. This parameter change enables accurate coding mode decisions in a one-pass encoding process without sacrificing encoding speed.
Data Source
AI summary
For each of plural blocks (e.g., 8×16 blocks) in a source interlaced video frame, a video encoder measures vertical intensity level fluctuation between neighboring lines and between alternating lines in the block, and determines an interlace effect status value for the block. For example, the encoder calculates a ratio between the fluctuations of neighboring and alternating lines and compares the ratio with one or more thresholds. The encoder also can measure horizontal intensity level fluctuation and compare it with vertical intensity fluctuation. The encoder determines a frame-level interlace coding mode (e.g., frame mode or field mode) for the frame based at least in part on the interlace effect status values. The encoder can represent a frame-level interlace coding mode decision with a bitstream element, and a decoder can perform one or more video decoding functions based at least in part on the value of the bitstream element.