Adaptive Video Compression via Packet Buffer Feedback
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Solution Overview
Problem
Transmitting streaming video over networks faces challenges due to bandwidth limitations, varying entropy in video streams, and issues with latency and network congestion, making it difficult to achieve optimal compression and quality without prior knowledge of the video stream's entropy characteristics, especially in live feeds.
Innovation Solution
A method and apparatus that adaptively compresses video streams using a variable rate compression engine, controlled by a packet buffer feedback system, which adjusts compression based on the buffer level to optimize quality for a given transport bandwidth, employing predefined compression vectors and packet delay control to manage bit rate effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed compression ratio is used, then the device complexity is reduced, but the video quality becomes suboptimal when entropy varies
Solution Approach 1:
The patent implements dynamic compression ratio adjustment by monitoring packet buffer levels and adapting the compression ratio accordingly. The system transitions from static to dynamic compression control, where the compression ratio is continuously adjusted based on real-time buffer status, allowing optimal video quality across varying entropy conditions without excessive complexity.
Solution Approach 2:
The patent employs feedback control by monitoring packet buffer levels and using this information to adjust the compression ratio. The buffer level serves as a feedback signal that drives compression ratio adaptation, creating a closed-loop system that automatically optimizes video quality based on actual transmission conditions.
2Productivity
If compression ratio is increased, then the bandwidth utilization is improved, but the video quality deteriorates
Solution Approach 1:
The system dynamically adjusts compression ratio based on packet buffer levels rather than using a fixed high compression ratio. When buffer levels indicate sufficient capacity, compression is relaxed to preserve quality; when buffers are full, compression is intensified to prevent overflow, optimizing the trade-off between bandwidth utilization and video quality in real-time.
Solution Approach 2:
The patent changes the compression ratio parameter dynamically based on buffer level conditions. By monitoring buffer occupancy and adjusting the compression ratio parameter accordingly, the system adapts to varying network conditions and video entropy, achieving optimal bandwidth utilization without persistent quality degradation.
3Manufacturing precision
If two pass encoding is used, then the video quality is optimized, but the latency increases for live feeds
Solution Approach 1:
The patent implements preliminary analysis of video entropy characteristics without requiring a complete two-pass encoding process. By performing lightweight entropy estimation on live feeds and using this information to guide compression ratio selection, the system achieves quality optimization similar to two-pass encoding but with minimal latency, suitable for real-time applications.
4Manufacturing precision
If compression ratio is decreased, then the video quality is maintained, but the buffer overflow risk increases
Solution Approach 1:
The system uses buffer level monitoring as feedback to dynamically adjust compression ratio. When buffer levels approach capacity, the feedback mechanism triggers increased compression to prevent overflow, while maintaining quality when buffer capacity is sufficient. This closed-loop control ensures reliable buffer management while preserving video quality.
Solution Approach 2:
The compression ratio parameter is adjusted based on buffer occupancy levels. When buffers are nearly full, the system increases compression ratio to reduce incoming data rate and prevent overflow; when buffers have available capacity, compression is reduced to maintain quality. This dynamic parameter adjustment balances quality and buffer reliability.
Data Source
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AI summary
The present invention is a method and apparatus for adaptively compressing and transmitting streaming video, preferably implemented in hardware as part of a codec, that adaptively applies a variable rate of compression to images in a video stream to optimize the quality attainable for a given transport bandwidth. In one or more embodiments, image frames from the video stream are divided into blocks, and a variable compression ratio compression engine compresses the blocks for transmission over a network. Depending on their compressed sizes, one or more of the compressed blocks are packaged into fixed size data packets for transmission over a network. The data packets are fed into a packet buffer. A packet servo releases packets from the buffer to achieve a desired transport data rate. The amount of compression applied by the compression engine is controlled based on the number of packets in the buffer. In one or more embodiments, a plurality of indexed compression vectors are predefined for the compression engine that provide increasing amounts of compression. In one or more embodiments, the index of the compression vector used by the compression engine is incremented when the buffer level of the packet buffer increases, and decremented when the buffer level decreases. In this manner the compression applied by the compression engine automatically adapts to changing entropy within the images of the video stream to optimize the video quality for a given transport data rate.