GOP Frame Position Control for Video Artifact Reduction
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Solution Overview
Problem
MPEG-based video encoding methods can produce imperfections or artifacts noticeable to the human visual system, especially at low system bandwidths due to the limitations in frame encoding modes and quantization processes.
Innovation Solution
A video data encoding method that dynamically controls block encoding modes in inter frames based on their position within a group of pictures, increasing intra-encoded and backward-predicted content as the frame position advances, to reduce forward inter-encoded frame content and improve perceived quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If inter-frame encoding is used to exploit temporal redundancy and reduce bitrate, then compression efficiency is improved, but visual quality deteriorates due to artifact propagation and fluctuations
Solution Approach 1:
The patent applies dynamics by making the encoding mode flexible and adaptable rather than fixed. The encoder dynamically selects between forward inter-encoded, backward inter-encoded, and intra-encoded modes based on frame position within the GOP and local content characteristics. This dynamic adaptation allows the system to optimize visual quality in regions prone to artifact propagation while maintaining compression efficiency, directly resolving the contradiction between bitrate reduction and visual quality preservation.
Solution Approach 2:
The patent implements local quality by applying different encoding strategies to different regions and frames within the GOP structure. Specifically, it increases intra-encoded and backward-predicted content in later frames of the GOP where artifact propagation is more severe, while using forward inter-encoded modes in earlier frames. This localized quality enhancement targets problem areas without sacrificing overall compression efficiency.
2Productivity
If forward inter-encoding is used throughout the GOP, then compression efficiency is maximized, but quality fluctuations and artifact propagation increase
Solution Approach 1:
The patent applies periodic action by systematically varying the encoding mode based on frame position within the GOP structure. It employs a periodic pattern where early frames use forward inter-encoding for compression efficiency, while later frames transition to backward inter-encoding or intra-encoding to reset artifact propagation. This periodic modulation of encoding modes maintains overall compression efficiency while ensuring quality consistency throughout the GOP sequence.
3Manufacturing precision
If quantization precision is increased to improve visual quality, then image fidelity is improved, but bitrate increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the encoding mode parameter based on frame position and content characteristics, rather than uniformly increasing quantization precision across all frames. By changing the encoding mode parameter (forward inter-, backward inter-, or intra-encoding) selectively in later GOP frames, the system achieves improved image fidelity in critical regions without the bitrate penalty associated with uniform high-precision quantization.
Data Source
AI summary
In some embodiments, a video encoding method includes controlling a set of block encoding modes in a plurality of inter video frames in a group of pictures (GOP) according to a frame position in the group of pictures, to generally decrease a forward inter-encoded frame content with the frame position in the group of pictures. An encoding mode determination is made for inter-frame encoding blocks (e.g. macroblocks) according to the frame position in the group of pictures. The determination may include forcing a block encoding mode to an intra, backward inter-predicted, or backward strong-weighted bi-predicted mode. The determination may be performed according to a frame type (P/B), frame position in GOP, frame content, a selected temporal and spatial pattern, a bit cost of making an encoding mode decision, and an available bit rate. The fraction of mode-forced blocks is generally increased as the GOP frame position advances.