Video Encoder Motion Estimation Under Memory Bandwidth Limits
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Solution Overview
Problem
Conventional video encoding methods, such as the MPEG 2 standard, face challenges in managing memory bandwidth, particularly during motion estimation, which can lead to increased memory requirements exceeding available bandwidth, resulting in decreased encoding performance and potential failure to achieve real-time encoding.
Innovation Solution
A method and apparatus for a video encoder that adaptively determines the encoding type and motion estimation type based on available memory bandwidth, adjusting search ranges and encoding types to ensure that memory bandwidth requirements do not exceed available resources, thereby ensuring real-time encoding capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If motion estimation with large search range is performed to improve encoding quality, then encoding quality is improved, but memory bandwidth requirement increases beyond available bandwidth
Solution Approach 1:
The patent dynamically adjusts the motion estimation search range based on available memory bandwidth. The controller monitors memory bandwidth conditions and adaptively modifies the search range parameter, transforming a static encoding parameter into a dynamic one that responds to system conditions, thereby resolving the contradiction between quality and resource consumption
Solution Approach 2:
The patent changes the search range parameter of motion estimation based on memory bandwidth availability. When memory bandwidth is sufficient, a larger search range is used for better quality; when bandwidth is limited, the search range is reduced to fit available resources. This parameter adaptation directly addresses the contradiction by making encoding quality controllable within bandwidth constraints
2Productivity
If reference pictures are stored and accessed for predictive encoding to improve compression ratio, then compression ratio is improved, but memory bandwidth requirement increases
Solution Approach 1:
The patent adjusts encoding parameters including reference picture usage based on available memory bandwidth. When bandwidth is sufficient, more reference pictures are utilized for better compression; when bandwidth is limited, the system reduces reference picture usage to lower memory demands, maintaining an optimal balance between compression ratio and bandwidth consumption
3Measurement precision
If high resolution search range is used in motion estimation to improve accuracy, then motion estimation accuracy is improved, but processing time increases
Solution Approach 1:
The patent dynamically adjusts the motion estimation search range based on real-time memory bandwidth conditions. When bandwidth is abundant, a larger and more accurate search range is employed; when bandwidth is constrained, the search range is reduced to decrease processing time. This dynamic adaptation resolves the contradiction between accuracy and processing time by making search range a variable parameter
Solution Approach 2:
The patent applies partial motion estimation by adjusting the search range to be just sufficient for the given bandwidth conditions rather than always performing exhaustive high-resolution search. This partial action approach achieves acceptable accuracy while significantly reducing processing time when full accuracy is not necessary given the bandwidth constraints
Data Source
AI summary
A method for a video encoder to encode video data into a video bit stream, the video data includes at least a picture, the picture includes a plurality of blocks, the method includes: receiving an available memory bandwidth value; determining an encoding type for the block according to the available memory bandwidth value; and encoding the block using the encoding type.