Adaptive Bit-Rate Streaming with Shifted Key Frames
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Solution Overview
Problem
Existing live media streaming technologies face challenges in minimizing start-up latency and re-buffering, particularly when client devices subscribe to higher bit-rate streams or experience changes in network conditions, leading to suboptimal user experience.
Innovation Solution
The implementation of adaptive bit-rate techniques and dynamically generated distribution layers with shifted key frames allows client devices to subscribe to media streams with reduced start-up latency and optimized quality, even under dynamic network conditions, by generating additional distribution layers based on client device requests and network changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a higher bit-rate video stream is selected, then video quality is improved, but start-up latency and re-buffering increase
Solution Approach 1:
The system performs preliminary actions by pre-generating multiple distribution layers with key frames at different time positions before client subscription. When a client subscribes, the server can immediately provide the appropriate distribution layer without waiting for key frame generation, thereby reducing start-up latency while maintaining high video quality through higher bit-rate streams.
Solution Approach 2:
The video stream is segmented into multiple distribution layers, each with different bit-rates and key frame positions. This segmentation allows clients to choose from multiple pre-prepared streams, enabling quick subscription to high-quality streams without the trade-off of increased start-up latency, as the segmentation is done in advance.
2Measurement precision
If a higher bit-rate video stream is selected, then video quality is improved, but re-buffering increases
Solution Approach 1:
Multiple distribution layers are pre-generated and made available before client subscription. This preliminary preparation ensures that high bit-rate streams are ready for immediate delivery, preventing re-buffering events that would otherwise occur while waiting for key frames to be generated and transmitted.
Solution Approach 2:
The system dynamically selects and switches between different distribution layers based on real-time network conditions and client device capabilities. This dynamic adaptation allows clients to maintain high video quality while avoiding re-buffering by switching to appropriate bit-rate streams as network conditions change.
3Adaptability or versatility
If additional distribution layers are generated dynamically, then adaptability to network conditions is improved, but system complexity increases
Solution Approach 1:
Instead of generating distribution layers dynamically when needed, the system performs the complex generation operation in advance, creating multiple distribution layers with different bit-rates and key frame positions before client subscription. This shifts the complexity burden from real-time operation to preliminary preparation, reducing real-time system complexity while maintaining high adaptability.
4Loss of time
If key frames are shifted in time across distribution layers, then start-up latency is reduced, but encoding complexity increases
Solution Approach 1:
The system performs the complex encoding operation with shifted key frames in advance, during the preliminary generation of distribution layers. This allows the encoding complexity to be handled during offline preparation rather than during real-time streaming, reducing real-time encoding complexity while achieving reduced start-up latency through the shifted key frame structure.
Data Source
AI summary
The following describes techniques to maintain continuity of a live media stream. A media stream includes a first distribution layer with a first set of key frames and a set of delta frames succeeding key frames in the first set of key frames. The media stream also includes a second distribution layer including a second set of key frames, where the second set of key frames contains fewer key frames than the first set of key frames. Using the first and second distribution layers, a client device may subscribe to the media stream with a minimized start-up time and optimized quality of experience among varying complexity of the media content and dynamic network conditions.