Cap-Based Streaming Rate Control for Bandwidth Stability
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Solution Overview
Problem
HTTP Adaptive Streaming (HAS) clients often experience instability and unfairness due to competing for bandwidth, leading to playback stalls and high bitrates that waste bandwidth, particularly affecting mobile clients with small screens.
Innovation Solution
A cap-based framework where the network and clients cooperate, using buffer-aware rate caps and boost-aware client-side adaptation algorithms to optimize bitrate selection, combined with information sharing to improve Quality of Experience (QoE) while reducing bandwidth waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HTTP adaptive streaming clients compete for bandwidth without rate caps, then clients can request high video quality bitrates, but this leads to playback stalls and unstable quality due to bandwidth competition
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the rate cap parameter based on network conditions and client buffer state. The rate cap is not fixed but adapts over time, changing from a restrictive initial cap to a higher cap when buffer conditions improve, thereby resolving the contradiction between playback stability and video quality delivery
Solution Approach 2:
The patent implements dynamics through the time-varying rate cap mechanism. The rate cap transitions from a static limiting value to a dynamic parameter that increases when buffer conditions improve and network conditions allow, enabling the system to adapt between stability-focused and quality-focused operation modes
2Loss of energy
If streaming services ignore client device context and stream video at high bitrates, then video quality may be high, but this wastes bandwidth and causes unfairness on metered links
Solution Approach 1:
The patent applies local quality by tailoring the streaming quality to each specific client device's capabilities and context. The rate cap and bitrate selection are customized per client based on device type, screen size, and network conditions, ensuring optimal quality without waste for each local context rather than uniform high-bitrate streaming to all clients
Solution Approach 2:
The patent implements feedback mechanisms where the client reports buffer state and device context to the server, which then adjusts the rate cap accordingly. This closed-loop feedback enables the system to adapt streaming parameters to match actual client needs and network conditions, preventing bandwidth waste while maintaining appropriate quality
3Reliability
If rate caps are applied to stabilize streaming, then playback stability improves, but startup times increase and stall recovery slows
Solution Approach 1:
The patent applies periodic action through time-based rate cap adjustments. The rate cap is applied restrictively during initial startup phase to ensure stable buffer filling, then periodically increased or removed as buffer conditions improve and stable playback is established, thereby reducing startup delay while maintaining stability during critical phases
Solution Approach 2:
The patent implements preliminary action by pre-applying rate caps during the startup phase before full bandwidth competition begins. This preliminary stabilization ensures buffers are filled reliably before high-rate streaming commences, preventing early stalls while allowing faster transition to higher quality once stability is established
Data Source
AI summary
Aspects of the subject disclosure may include, for example, setting a streaming rate cap for a client device; obtaining a bitrate ladder associated with the client device, wherein the bitrate ladder comprises a listing of a plurality of bitrates that the client device can request in connection with receiving streaming data; determining a boost rate for the client device, wherein the boost rate is greater than the streaming rate cap such that the boost rate enables the client device to receive the streaming data faster than the client device would otherwise receive the streaming data under the streaming rate cap, and wherein the boost rate is based upon the bitrate ladder; and enabling delivery to the client device of the streaming data up to the boost rate; wherein a network device is part of a network through which the streaming data is delivered to the client device. Other embodiments are disclosed.