Variable Bit Video Streams Adaptive Streaming
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Solution Overview
Problem
Adaptive streaming solutions face challenges when using variable bit rate (VBR) video streams, as the average bit rate is not reflective of scene complexity, leading to ineffective switching between encoded video streams and reduced playback quality.
Innovation Solution
A method that involves generating a scene complexity map to dynamically select portions of video data from different constant bit rate encoded streams based on estimated bandwidth and complexity levels, optimizing playback quality by switching between encoded video streams during playback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If variable bit rate (VBR) encoding is used to optimize bandwidth utilization, then file size and bandwidth usage are reduced, but the average bit rate becomes unrepresentative of scene complexity, leading to ineffective stream switching and reduced playback quality
Solution Approach 1:
The video stream is segmented into multiple Constant Bit Rate (CBR) encoded streams, each optimized for specific complexity levels (low, medium, high). This segmentation allows the system to select appropriate streams based on actual scene complexity rather than relying on an unrepresentative average bit rate from VBR encoding.
Solution Approach 2:
The patent changes the encoding parameter from variable bit rate to multiple constant bit rate streams with different complexity profiles. By providing multiple CBR streams with known bit rates and complexity characteristics, the system can reliably match stream parameters to both network conditions and scene requirements.
2Reliability
If multiple encoded video streams with different bit rates are provided for adaptive streaming, then playback quality can be optimized according to network conditions, but switching between streams becomes ineffective when VBR encoding is used due to mismatch between average bit rate and actual scene bit rate
Solution Approach 1:
The video content is divided into multiple CBR-encoded stream versions, each with distinct bit rates and corresponding complexity characteristics. This segmentation enables reliable stream switching because each stream's actual bit rate matches its labeled parameters, making selection and switching decisions straightforward and effective.
Solution Approach 2:
Each encoded stream is created with homogeneous bit rate characteristics (Constant Bit Rate encoding ensures uniform bit allocation). This homogeneity makes stream switching reliable because the system can predict the actual bit rate of each stream without dealing with the variability inherent in VBR encoding.
3Ease of operation
If the content player selects video streams based on average bit rate, then stream selection is simplified, but the selection becomes inappropriate when VBR encoding is used because the average bit rate does not reflect the bit rate of specific scenes
Solution Approach 1:
Multiple CBR-encoded streams are prepared in advance, each with known and consistent bit rate characteristics. This preliminary preparation eliminates the need for complex runtime analysis of VBR streams, allowing simple and accurate stream selection based on predefined parameters that precisely reflect actual scene bit rates.
Solution Approach 2:
The patent changes from selecting based on average bit rate of VBR streams to selecting from multiple CBR streams with precise, known bit rates. This parameter change improves both selection simplicity and bit rate accuracy because CBR streams provide reliable, predictable parameters without requiring complex averaging or estimation.
Data Source
AI summary
One embodiment of the present invention sets forth a technique for adapting playback bit rate in a content delivery system based on scene complexity of the video content as well as network conditions and other performance factors. A scene complexity map of the video content indicates the complexity levels of different scenes within the video content. Using the scene complexity map, a content player may download scenes of lower scene complexity levels from video streams encoded to lower bit rates to manage the bandwidth consumed to download the video content and allow for the downloading of scenes of higher complexity levels from video streams encoded to higher bit rates.