Adaptive Video Stream Encoding for Low-Delay Bitrate Switching
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Solution Overview
Problem
Existing adaptive bitrate streaming systems face challenges in seamlessly switching between different bitrates to maintain smooth playback without stalls, particularly due to variations in network bandwidth, which can lead to underflow issues.
Innovation Solution
Encoding video streams with varying bitrates to have upper and lower bound seek delays, ensuring seamless switching by buffering media to match network conditions, using H.264 standard encoding with SEI buffering messages for delay information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If variable bitrate encoding is used to improve encoding efficiency, then encoding efficiency is improved, but the maximum bitrate is limited by the buffer size to prevent underflow
Solution Approach 1:
The patent segments the video stream into multiple alternative bitrates (e.g., 720p at 2 Mbps, 1080p at 4 Mbps) and provides separate buffering mechanisms for each bitrate stream. This allows the system to maintain high encoding efficiency for each segment while ensuring playback stability through dedicated buffer management for each bitrate level.
Solution Approach 2:
The patent implements preliminary buffering of video data at different bitrates before playback begins. By pre-buffering content at multiple quality levels and tracking the seek delay for each stream, the system ensures that sufficient data is available to switch between bitrates smoothly, preventing underflow during transitions.
2Reliability
If the buffer size is increased to prevent underflow, then playback stability is improved, but the seek delay increases causing slower switching between bitrates
Solution Approach 1:
The patent dynamically adjusts the buffer size and seek delay parameters based on network conditions and playback requirements. The system monitors actual buffering needs and modifies the buffer configuration in real-time, allowing optimal balance between stability and switching speed rather than using fixed conservative values.
Solution Approach 2:
The patent implements feedback mechanisms that track the actual seek delay experienced by players and adjust the buffering strategy accordingly. By monitoring which bitrate streams experience the least seek delay under current network conditions, the system optimizes buffer management to minimize time loss while maintaining stability.
3Adaptability or versatility
If multiple alternative streams are encoded at different bitrates to enable adaptive streaming, then adaptability is improved, but the complexity of managing and switching between streams increases
Solution Approach 1:
The patent creates a universal buffer management framework that handles multiple bitrate streams using the same core mechanisms. The same buffering logic, seek delay calculation methods, and switching algorithms are applied across all alternative streams, simplifying the management of multiple bitrates rather than requiring separate specialized handling for each.
Solution Approach 2:
The patent manages multiple streams by systematically varying key parameters such as bitrate, resolution, and buffer size in a controlled manner. By establishing clear parameter relationships (e.g., how buffer size relates to seek delay for each bitrate), the system reduces the complexity of managing variations while maintaining adaptability across different quality levels.
Data Source
AI summary
Systems and methods for encoding alternative streams for use in adaptive bitrate streaming based upon the delay of each stream in accordance with embodiments of the invention are described. One embodiment of the invention includes memory, and a processor configured by a source encoding application to: receive multimedia content, where the multimedia content includes source video data having a primary resolution and a primary sample aspect ratio; and encode the source video data as a set of alternative video streams, where: the alternative video streams have different maximum bitrates; and the alternative video streams are encoded to have an upper bound seek delay that is equal to or less than the upper bound seek delay of streams in the set of alternative video streams that are encoded at a higher maximum bitrate.