Moving Picture Encoder Time-Constrained Search
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Solution Overview
Problem
Conventional moving picture encoder devices face challenges in completing the encoding process within a predetermined time frame due to difficulties in appropriately setting the search range for reference macroblocks, leading to potential frame dropouts and decreased encoding efficiency.
Innovation Solution
The proposed solution involves a moving picture encoder device with search means that allocates time for searching reference pixel blocks based on a predetermined threshold, stopping the search when the allocated time is reached, and reallocating remaining time to subsequent blocks, while also considering motion prediction and spatial frequency components to optimize the selection of reference blocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the search range is extended to find an appropriate reference macroblock, then the encoding efficiency is improved, but the amount of arithmetic operations increases and the encoding time exceeds the frame cycle
Solution Approach 1:
The patent applies preliminary action by performing motion prediction before the full search process. The motion prediction unit calculates predicted motion vectors in advance, which are then used to initialize and constrain the subsequent search process. This preliminary calculation provides a starting point that reduces the search space and ensures the encoding process can complete within the frame cycle while still achieving good encoding efficiency.
Solution Approach 2:
The patent segments the encoding process into distinct stages: motion prediction stage and search stage. The motion prediction unit handles the preliminary estimation separately from the main search process. This segmentation allows each stage to be optimized independently, with motion prediction providing quick initial estimates and the search stage refining these estimates within the remaining time budget.
2Productivity
If a predetermined search range is set to limit arithmetic operations, then the encoding time is reduced, but the possibility of selecting an appropriate reference macroblock decreases
Solution Approach 1:
The patent applies dynamics by making the search range adaptive rather than fixed. The search range is dynamically adjusted based on the motion prediction results and the time remaining in the frame cycle. For regions with high motion, the search range is automatically extended, while for low-motion regions, the search range remains constrained. This dynamic adjustment ensures both encoding speed and efficiency are optimized according to local image characteristics.
Solution Approach 2:
The patent applies local quality by allowing different search ranges for different macroblocks within the same frame. Instead of using a uniform search range for all blocks, the system adapts the search range locally based on motion prediction results. High-motion regions receive larger search ranges while low-motion regions use smaller ranges, optimizing both speed and efficiency for each local region.
3Device complexity
If the search uses a threshold-based approach instead of minimum search, then the arithmetic operations are reduced, but frame dropout occurs when motion is larger than expected
Solution Approach 1:
The patent uses motion prediction as a preliminary action to establish an initial search range based on threshold criteria. This preliminary estimation allows the system to quickly identify regions of interest without exhaustive searching. The threshold-based motion prediction provides a fast initial filter that guides the subsequent search, reducing arithmetic operations while maintaining reliability through the two-stage approach.
4Reliability
If the search range is adaptively controlled based on image properties, then the encoding efficiency is improved, but it is not always easy to appropriately set the range of search
Solution Approach 1:
The patent applies universality by using motion prediction as a multi-functional tool that serves both as a search range estimator and as a preliminary filtering mechanism. The motion prediction unit performs multiple functions: estimating motion, initializing search parameters, and guiding the adaptive search range control. This multi-functionality simplifies the overall system while maintaining adaptive search capabilities.
Data Source
AI summary
A motion vector detection section detects as a reference macroblock a reference pixel block with which a sum of differences in pixel data between a target macroblock and each pixel is equal to or smaller than a predetermined threshold among macroblocks in a reference frame. An intraframe time management section measures a detection time. If an allocated predetermined detection time has elapsed before detection of such a reference macroblock, the detection processing is stopped. In this case, a macroblock with which the previously-calculated sum is minimum is selected as a reference macroblock.