Hybrid Video Repeat Padding for Macroblock Alignment
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Solution Overview
Problem
Existing video compression standards face challenges in efficiently encoding and decoding hybrid video sequences with arbitrary video resolutions, particularly due to restrictions on macroblock alignment and the need for repeat padding, which introduces overhead and affects prediction accuracy.
Innovation Solution
The technique involves different repeat padding methods for progressive and interlaced pictures within hybrid video sequences, where progressive pictures vertically pad by repeating edge rows and interlaced pictures vertically pad by repeating the last two rows, allowing for better prediction areas and minimizing the need for transmission of expanded regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If repeat padding is applied to meet macroblock alignment requirements, then encoding compatibility is improved, but encoding overhead increases
Solution Approach 1:
The patent applies repeat padding to reference pictures before motion estimation and compensation to pre-establish prediction areas that extend beyond the original picture boundaries. This preliminary action enables macroblocks in subsequent frames to reference pixels outside the original picture without requiring actual transmission of those expanded region data, thus maintaining encoding compatibility while avoiding the overhead of transmitting padding data.
2Measurement precision
If repeat padding is applied to expand prediction areas, then prediction accuracy is improved, but information transmission increases
Solution Approach 1:
The patent creates prediction areas by copying (repeating) edge pixels of the reference picture to form an expanded region. This copying provides motion estimation with access to boundary pixels that would otherwise be unavailable, improving prediction accuracy for macroblocks near picture edges. However, since these copied pixels are not transmitted but rather reconstructed at the decoder using the same repeat padding technique, actual information transmission does not increase.
3Manufacturing precision
If different repeat padding methods are used for progressive and interlaced pictures, then processing precision is improved, but device complexity increases
Solution Approach 1:
The patent applies different repeat padding strategies tailored to the specific characteristics of progressive versus interlaced pictures. For progressive pictures, one padding method is used that optimizes for their structure, while for interlaced pictures, a different method accounts for their field-based nature. This localized approach improves processing precision for each picture type while the complexity increase is managed through systematic implementation of the differentiated rules.
Data Source
AI summary
A video codec provides efficient repeat padding of hybrid video sequences having arbitrary video resolution. The video codec repeat pads to expand the active content of pictures in the video sequence out to meet an adaptive vertical macroblock alignment restriction that varies by picture type. For progressive type pictures, the video codec repeats the last row or horizontal boundary edge of the active content. For interlaced type pictures, the video coded repeats the last two rows (last row of each interlaced field) of the active content. This repeat padding differing by picture type provides a better prediction (lower prediction error residual) for macroblocks in following predicted frames whose motion vector points into the padded region.