Intra-encoding Noise Alignment for I-frame Flicker Reduction
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Solution Overview
Problem
Conventional moving picture encoding techniques suffer from visually conspicuous flickering, known as I-frame flickering, due to differences in noise patterns between intra-encoding and inter-encoding, especially when encoding scenes in motion or using inter-frame predictions like P- and B-frames, and existing solutions fail to effectively reduce this issue at low bit rates or when combined with inter-frame prediction.
Innovation Solution
The proposed solution involves intra-encoding using a reconstructed image frame that has been encoded using inter-encoding, specifically utilizing a past P-frame for correction through inter-frame prediction, quantization, and inverse-conversion to align the noise pattern with inter-encoding, thereby reducing I-frame flickering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If intra-encoding is used for image frames, then encoding flexibility and reference frame utilization are improved, but I-frame flickering occurs due to noise pattern differences between intra-encoding and inter-encoding
Solution Approach 1:
The patent introduces an inter-encoded reconstructed image frame as an intermediary reference for intra-encoding. Instead of directly using the original image frame, the intra-encoding process uses a past P-frame (inter-encoded and reconstructed) as the reference frame. This intermediary reference frame has noise characteristics similar to inter-encoding, thereby reducing the noise pattern difference and minimizing I-frame flickering while preserving encoding flexibility.
Solution Approach 2:
The patent changes the parameter of the reference frame used in intra-encoding from the original image frame to an inter-encoded and reconstructed image frame. By modifying which frame serves as the reference (changing the reference frame parameter), the noise characteristics of the intra-encoding process are aligned more closely with inter-encoding, reducing flickering effects.
2Ease of manufacture
If conventional intra-encoding is used, then encoding simplicity is maintained, but noise pattern differences cause visually conspicuous flickering
Solution Approach 1:
The patent uses an inter-encoded reconstructed image frame as a mediator between the original image and the intra-encoding process. This intermediary frame carries the noise characteristics of inter-encoding, and when used as a reference for intra-encoding, it reduces the noise pattern difference without significantly complicating the encoding process.
3Productivity
If inter-frame prediction is used for P- and B-frames, then compression efficiency is improved, but the noise pattern difference with I-frames increases causing flickering
Solution Approach 1:
The patent introduces an inter-encoded reconstructed image frame as an intermediary that bridges the noise pattern gap between inter-encoding (P/B-frames) and intra-encoding (I-frames). By using this intermediary reference frame in intra-encoding, the noise characteristics become more consistent across different frame types, reducing flickering while maintaining the compression efficiency benefits of inter-frame prediction.
Solution Approach 2:
The patent changes the reference frame parameter in intra-encoding from the original image to an inter-encoded reconstructed image. This parameter change aligns the noise characteristics of I-frames with P/B-frames, reducing flickering while preserving compression efficiency.
Data Source
AI summary
If a reference frame displayed at the reproduction side immediately before a current image frame to be encoded is an inter encoding image frame, a quantization control device (999) appropriately corrects the level (quantization value) of an intra encoding so as to visually reduce I-frame flicker caused by a difference between the inter encoding noise characteristic of the inter encoding image frame and the noise characteristic of the current intra encoding.