Video Encoding Refresh Scheme Zone Quantization
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Solution Overview
Problem
Existing video encoding techniques using a refresh scheme can cause visual artifacts and decoding delays due to forced intra-mode encoding in static scenes, leading to sudden drops in image quality.
Innovation Solution
A method and encoder that evaluate frame-by-frame whether to encode in intra-mode or inter-mode, applying a refresh scheme to forcibly encode in intra-mode occasionally, and quantize frames with higher resolution when forced to intra-mode to maintain image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a refresh scheme forcibly encodes zones in intra-mode for one out of several successive frames, then reference frames occur frequently preventing long decoding delays, but visual artifacts and sudden drops in image quality occur in static scenes
Solution Approach 1:
The patent applies different quantization resolutions to different zones within a frame based on their encoding mode. Zones forcibly encoded in intra-mode receive higher quantization resolution (lower quantization parameter values) while zones encoded in inter-mode use standard quantization. This local differentiation allows the refresh scheme to maintain image quality in specific zones without degrading overall video quality or creating visual artifacts.
Solution Approach 2:
The patent dynamically changes the quantization parameter (QP) based on the encoding mode and zone characteristics. When a zone is forcibly encoded in intra-mode by the refresh scheme, the QP is adjusted to provide higher resolution. This parameter adaptation ensures that the forced intra-mode encoding does not result in visible quality drops, as the quantization is optimized for each specific encoding scenario.
2Reliability
If zones in static scenes are forcibly encoded in intra-mode by the refresh scheme, then reference frames occur frequently, but the amount of data increases significantly
Solution Approach 1:
The patent applies higher quantization resolution (and thus higher data usage) only to zones that are forcibly encoded in intra-mode by the refresh scheme, while other zones continue to use standard quantization. This localized approach ensures that reference frames are properly maintained where needed without unnecessarily increasing the overall data amount for the entire frame.
Solution Approach 2:
The patent applies the refresh scheme partially by selecting specific zones within frames for forced intra-mode encoding rather than applying it to entire frames. This partial application reduces the overall data increase while still achieving the goal of providing frequent reference frames in critical areas, balancing reliability requirements with data efficiency.
3Productivity
If the inter-mode is used for zones in static scenes to produce smallest data amount, then data efficiency is improved, but decoding delay increases when no intra-mode reference frame is available
Solution Approach 1:
The refresh scheme implements periodic forced intra-mode encoding at regular intervals (one out of several successive frames) for specific zones. This periodic action ensures that reference frames are available at predictable intervals, preventing long decoding delays while allowing inter-mode encoding to be used in between refresh intervals for data efficiency.
Solution Approach 2:
The refresh scheme proactively inserts intra-mode encoded zones into the video stream at predetermined intervals before decoding delays can occur. This preliminary action ensures that reference frames are available in advance, allowing decoders to maintain proper synchronization and avoid delays without requiring continuous intra-mode encoding.
Data Source
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AI summary
A sequence of frames is encoded in the following manner. An evaluation on a frame-by- frame basis is made for at least a zone in a series of successive frames whether the zone should be encoded in an intra-mode or in an inter-mode. A refresh scheme is applied that frequently causes the zone to be forcibly encoded in the intra-mode for one out of several successive frames, irrespective of the evaluation made. The zone in the series of successive frames is quantized so that if, for a frame, the zone is forcibly encoded in the intra-mode and contrary to the evaluation that was made, the zone is quantized with a higher resolution than if the zone were encoded in accordance with the evaluation that was made in one of the following modes: the intra-mode and the inter-mode.