QVBR Encoding for Uniform Video Quality
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Solution Overview
Problem
Existing video encoding technologies, such as constant bitrate (CBR) and variable bitrate (VBR) modes, fail to maintain consistent video quality across different content segments, leading to bandwidth waste and noticeable quality variations, which degrade the viewing experience.
Innovation Solution
The implementation of quality-defined variable bitrate (QVBR) encoding, which uses machine learning models to predict quantization parameters based on content analysis, allocating bits dynamically to ensure consistent quality by adjusting bitrate according to the complexity of video segments, thereby optimizing bandwidth usage and visual quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If constant bitrate (CBR) encoding is used, then bandwidth usage is predictable and simple, but video quality varies noticeably across different content segments and bandwidth is wasted
Solution Approach 1:
The patent implements dynamic bitrate allocation by analyzing video content complexity and adjusting the bitrate accordingly. The system transitions from static CBR to dynamic VBR encoding, where the encoder continuously adapts the bitrate based on real-time assessment of scene complexity, motion intensity, and detail density, thereby maintaining consistent quality while optimizing bandwidth usage.
Solution Approach 2:
The patent applies local quality enhancement by allocating higher bitrates to complex video segments requiring more detail and lower bitrates to simpler segments. The system identifies regions of interest and complex areas within frames and directs more encoding resources to these specific locations, ensuring uniform perceived quality across diverse content types.
2Loss of energy
If variable bitrate (VBR) encoding is used, then bandwidth is optimized by reducing allocation to simple segments, but quality consistency across segments deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where the encoder continuously monitors encoding quality metrics and adjusts bitrate allocation in real-time. The system measures actual quality outcomes and uses this feedback to refine subsequent encoding decisions, ensuring that quality consistency is maintained while achieving bandwidth optimization through adaptive VBR encoding.
Solution Approach 2:
The patent performs preliminary analysis of video content before encoding to identify complex and simple segments. By pre-assessing scene complexity, motion characteristics, and detail density, the system can proactively allocate appropriate bitrates to different segments, preventing quality inconsistencies before they occur while optimizing overall bandwidth usage.
3Manufacturing precision
If higher bitrate is used throughout the video, then quality consistency is maintained, but bandwidth consumption increases significantly
Solution Approach 1:
The patent dynamically changes encoding parameters including bitrate, quantization scale, and compression settings based on the complexity of each video segment. By adjusting these parameters in response to content characteristics, the system maintains consistent quality output while significantly reducing overall bandwidth consumption compared to uniform high-bitrate encoding.
Data Source
AI summary
Techniques for providing content aware uniform quality for quality-defined variable bitrate encoding of videos are described. According to some embodiments, a computer-implemented method includes receiving a request at a content delivery service to encode a live video at a quality level of a plurality of quality levels of a quality-defined variable bitrate encoding, determining features for a frame of the live video, generating a first predicted quantization parameter for the frame by a first machine learning model, trained for a first objective quality metric, receiving an input of the features and the quality level, performing a real time encode of the live video based at least in part on the first predicted quantization parameter to generate an encoded live video, and transmitting the encoded live video to a viewer device.