PTZ Camera Video Encoder Using Motion-Aware Block Segmentation
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Solution Overview
Problem
PTZ cameras experience high bit rates during pan/tilt motions due to extensive use of costly I-block encoding, leading to increased computational complexity and potential video quality reduction.
Innovation Solution
The method involves defining areas in the video stream based on camera movement, using I-block encoding for new areas and selecting between I-block, P-block, and P-skip encoding for overlapping areas using a block matching algorithm, while increasing thresholds to reduce I-block usage and optimize processing power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If I-block encoding is used for all blocks during pan/tilt motion, then video quality is maintained, but bit rate increases significantly
Solution Approach 1:
The image frame is divided into multiple blocks, and each block is independently classified into stationary or moving regions based on camera motion parameters. This segmentation allows different encoding strategies to be applied to different regions, reducing the overall bit rate while maintaining quality in important stationary areas.
Solution Approach 2:
Different encoding qualities are applied locally to different regions of the image. Stationary regions use more efficient P-block or P-skip encoding, while moving regions use I-block encoding. This local differentiation maintains video quality in critical areas while reducing bit rate overall.
2Measurement precision
If motion vector search range is increased to handle camera pan/tilt motion, then encoding accuracy improves, but computational complexity increases
Solution Approach 1:
Camera motion parameters (pan/tilt speed, direction) are obtained in advance from the camera device before the encoding process begins. This preliminary information is used to pre-classify blocks into stationary or moving regions, eliminating the need for extensive motion vector searches and reducing computational complexity while maintaining accuracy.
Solution Approach 2:
Camera motion parameters serve as an intermediary between the camera device and the encoding process. These parameters provide indirect information about block motion, allowing the encoder to make accurate classifications without performing computationally intensive motion estimation algorithms.
3Manufacturing precision
If block matching algorithm is performed for all blocks, then encoding precision improves, but processing time increases
Solution Approach 1:
The block matching algorithm is applied selectively only to blocks identified as belonging to moving regions, rather than performing the algorithm on all blocks in the image. This partial application maintains encoding precision for moving areas while significantly reducing overall processing time.
Solution Approach 2:
Blocks are pre-classified into stationary or moving regions using camera motion parameters before the encoding process. This preliminary classification allows the encoder to skip unnecessary block matching operations for stationary blocks, reducing processing time while maintaining precision for moving blocks.
4Quantity of substance
If P-block or P-skip encoding is used during camera motion, then bit rate decreases, but video quality deteriorates
Solution Approach 1:
Different encoding methods are applied locally to different regions: P-block or P-skip encoding is used for stationary regions to reduce bit rate, while I-block encoding is used for moving regions to maintain video quality. This local differentiation resolves the trade-off between bit rate and quality.
Solution Approach 2:
The image is segmented into stationary and moving regions based on camera motion analysis. This segmentation enables the selective application of compression techniques, allowing aggressive compression in stationary areas while preserving quality in moving areas through I-block encoding.
Data Source
AI summary
A method is performed in an encoder for encoding a video stream captured by a camera, and a computer program product and encoder implementing the method.