Media Display System Evaluating Macro-Block Scores for Random Access
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Solution Overview
Problem
Intra-refresh encoding in video applications makes it difficult to achieve random access due to the lack of key frames, resulting in poor visual quality and mosaics when decoding frames after a random access point, as inter-MBs rely on previously decoded reference frames which are often skipped.
Innovation Solution
A display system that includes a decoder and an evaluation unit to score macro blocks (MBs) in the current frame, with intra-MBs scored as a predetermined value and inter-MBs scored based on previously decoded frames, allowing the system to identify a qualified frame for seamless display by calculating scores of prediction blocks and their corresponding reference blocks, and signaling the display to skip or start from this frame.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If intra-refresh encoding is used to achieve uniform channel bandwidth utilization, then bandwidth utilization is improved, but random access capability deteriorates due to lack of key frames
Solution Approach 1:
The system performs preliminary evaluation of macro blocks before display by calculating scores based on prediction block differences and reference frame quality. This advance assessment allows the system to pre-identify frames suitable for display after random access, eliminating the need to wait and evaluate frames sequentially after accessing the bitstream.
Solution Approach 2:
The patent introduces an evaluation unit that acts as an intermediary between the decoder and display. This unit calculates scores for macro blocks using reference frames and prediction blocks, providing a quality metric that enables intelligent frame selection. The evaluation unit mediates the conflict between intra-refresh encoding and random access by providing data-driven guidance on which frames to display.
2Productivity
If frames are decoded using inter-MBs based on previously decoded reference frames, then compression efficiency is improved, but visual quality deteriorates after random access due to skipped reference frames
Solution Approach 1:
The system implements feedback by using previously decoded reference frames to evaluate the quality of current frame macro blocks. The evaluation unit calculates scores by comparing prediction blocks with reference blocks, creating a feedback loop that assesses decoding quality. This feedback mechanism allows the system to identify frames with acceptable visual quality even when reference frames are skipped during random access.
Solution Approach 2:
The patent changes the parameter used for frame selection from traditional key frame detection to a quality score based on macro block evaluation. By calculating scores based on prediction block differences and reference frame quality, the system transforms the frame selection criterion into a continuous quality metric, allowing flexible selection of frames with satisfactory visual quality after random access.
3Manufacturing precision
If the system skips frames after random access to find a suitable display frame, then display quality is improved, but display delay increases
Solution Approach 1:
The evaluation unit performs quality assessment of macro blocks in advance during the decoding process, before the frames need to be displayed. By calculating scores based on prediction blocks and reference frames during decoding, the system prepares quality metrics proactively, enabling rapid frame selection immediately after random access without requiring extensive frame skipping and evaluation.
Solution Approach 2:
The patent replaces the mechanical approach of sequential frame skipping and visual quality assessment with an automated scoring system. The evaluation unit uses algorithmic calculation of macro block scores based on prediction block differences and reference frame quality, substituting manual or trial-and-error frame selection with a deterministic, efficient scoring mechanism that reduces display delay.
Data Source
AI summary
A display system for displaying a media stream based on a given access point includes a decoder for decoding frames of the media stream, and an evaluation unit for scoring macro blocks (MBs) of a current frame. A score of an intra-MB is defined as a predetermined value, and a score of an inter-MB is generated based on scores of MBs in previously decoded frames. A controller signals a display to skip the current frame or start to display the media stream from a qualified frame identified using the scores of the MBs of at least the current frame.