Video Encoder Dynamic GOP and Compression Adjustment
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Solution Overview
Problem
Digital video encoding systems face challenges in balancing available bandwidth with image quality, particularly in network camera monitoring systems, where bit rate limits often result in low image quality during motion in scenes, compromising the ability to identify intruders or capture detailed information.
Innovation Solution
A method and system that dynamically adjust the Group of Pictures (GOP) length and compression values based on the level of motion and light in a scene, allowing higher bit rates during motion in well-lit conditions and lower bit rates in dark or static conditions, without applying a fixed bit rate limit, thereby optimizing bandwidth usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a bit rate limit is applied to all cameras, then the available bandwidth is sufficient for transmission, but the image quality becomes undesirably low during motion in the scene
Solution Approach 1:
The patent applies dynamic adjustment of GOP length and compression values based on real-time scene conditions (motion detection and light level sensing). When motion is detected and light levels are adequate, the system increases GOP length and reduces compression to maintain high image quality. When no motion is detected or light levels are low, the system reduces GOP length and increases compression to save bandwidth. This dynamic adaptation resolves the contradiction by making bandwidth usage and image quality adjustable according to actual needs rather than applying a static bit rate limit.
Solution Approach 2:
The patent changes encoding parameters (GOP length and compression value) based on scene conditions. The GOP length is adjusted as a decreasing function of motion level, and compression values are adjusted as a decreasing function of light level. These parameter changes allow the system to optimize the trade-off between bandwidth usage and image quality dynamically, rather than being constrained by a fixed bit rate limit.
2Quantity of substance
If a bit rate limit is applied to control encoding, then transmission bandwidth is ensured, but severe compression is required even for images with lots of details
Solution Approach 1:
The system dynamically adjusts compression values based on light level conditions. When light levels are high (above threshold), the compression value is reduced to preserve image details. When light levels are low (below threshold), higher compression is applied since detail preservation is less critical in dark conditions. This dynamic parameter adjustment eliminates the need for severe compression during well-lit scenes with important details.
3Manufacturing precision
If GOP length is increased to improve image quality during motion, then more bandwidth is consumed, but if GOP length is decreased to save bandwidth, image quality during motion deteriorates
Solution Approach 1:
The patent directly addresses this contradiction by making GOP length a decreasing function of detected motion level. When motion is detected (high motion level), GOP length is increased to capture more temporal information and maintain image quality. When no motion is detected (low motion level), GOP length is decreased to reduce bandwidth consumption. This conditional parameter adjustment optimizes the trade-off between image quality and bandwidth usage based on actual scene requirements.
Data Source
AI summary
Input video frames are encoded into a sequence of output video frames arranged in groups of pictures (GOP). Each input video frame is encoded into an output video frame using a respective compression value. Each GOP in the sequence of output video frames has a GOP length defined by a number of frames contained in the GOP. A level of motion and a level of light in a first input video frame are determined. If level of light is below a predetermined threshold value, encode the first input video frame using a predetermined constant GOP length and a compression value which is a decreasing function of the level of light. If level of light is above, encode the first input video frame using a GOP length which is a decreasing function of the level of motion, and a compression value which is a decreasing function of the level of light.