ABR Control System for Live OTT Streaming
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current Adaptive Bit Rate (ABR) adjustments in IP networks for live media distribution introduce significant delays due to buffering and continuous bitrate changes, failing to maintain live TV standards as defined by the European Broadcasting Union, with initial delays ranging from 30 seconds to several minutes and frequent disruptions.
Innovation Solution
A method for controlling ABR level upshifts in IP networks by initiating network probing to determine if a higher bitrate is applicable, monitoring network characteristics, and adjusting the bitrate only when capacity allows, thereby reducing unnecessary adjustments and maintaining image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If buffering is used to absorb network variances and ensure continuous video playback, then video playback stability is improved, but distribution delay increases significantly (from 30 seconds to several minutes)
Solution Approach 1:
The system performs preliminary actions by pre-fetching video segments only when network conditions predict sufficient bandwidth, and by using probing techniques to assess network capacity before committing to buffer accumulation. This allows the system to prepare for playback without unnecessarily accumulating large buffers, thus reducing delay while maintaining stability.
Solution Approach 2:
The buffering strategy is made dynamic by continuously monitoring network conditions (bandwidth, jitter, packet loss) and adjusting the buffer fill target accordingly. When network conditions are favorable, the system allows smaller buffers; when conditions deteriorate, it dynamically increases buffer accumulation. This dynamic adaptation resolves the contradiction by making buffer size conditional rather than fixed.
2Adaptability or versatility
If continuous ABR adjustments are made based on buffer fill level to adapt to network capacity changes, then adaptability to network conditions is improved, but video quality stability deteriorates due to frequent bitrate changes
Solution Approach 1:
Instead of continuous ABR adjustments, the system implements periodic probing at defined intervals to assess network capacity. ABR changes are triggered only by significant threshold crossings in network conditions or at scheduled probing points, not continuously. This periodic approach reduces the frequency of bitrate changes while maintaining adaptability to genuine network condition changes.
Solution Approach 2:
The system uses feedback mechanisms where ABR adjustment decisions are based on monitored network parameters (bandwidth estimates, packet loss rates, jitter) and buffer status. The feedback loop includes hysteresis and threshold-based triggering to avoid oscillations, ensuring that bitrate changes occur only when network conditions clearly warrant them, thus maintaining quality stability while adapting to capacity changes.
3Adaptability or versatility
If TCP congestion avoidance mechanisms are used to adjust retransmission rate and share bandwidth fairly, then network fairness is improved, but playback delay increases due to retransmission waiting and buffer accumulation
Solution Approach 1:
The system performs preliminary network probing and bandwidth estimation before video playback begins and during periodic intervals. By predicting available bandwidth in advance, the system can pre-position appropriate video segments in the buffer without waiting for TCP retransmissions to confirm bandwidth availability, thus reducing delay while maintaining fair bandwidth usage through informed rate selection.
Solution Approach 2:
The system skips the traditional TCP-centric approach where playback must wait for congestion signal confirmation and buffer re-filling. Instead, it rushes ahead by proactively selecting bitrate levels based on current network estimates and maintaining minimal necessary buffers, effectively skipping the delay-inducing waiting period for TCP congestion control to manifest and respond.
4Reliability
If multiple consecutive video segments are buffered to ensure continuous playback, then playback continuity is improved, but initial delay increases to at least 30 seconds
Solution Approach 1:
The system implements dynamic buffer management where the target buffer fill level is not fixed but adapts based on real-time network conditions, video segment duration, and playback position. When network conditions are stable and bandwidth is sufficient, the system maintains smaller buffers (reducing initial delay). When conditions are volatile or bandwidth is limited, it dynamically increases buffer accumulation to ensure continuity, thus resolving the contradiction through adaptive buffer sizing.
Solution Approach 2:
The system changes key parameters (buffer size target, segment pre-fetch count, bitrate selection) based on monitored network conditions and playback state. By dynamically adjusting these parameters, the system can reduce initial delay when conditions permit while ensuring playback continuity when conditions require it, thus resolving the fixed contradiction through parameter adaptation.
Data Source
Figure 1~2
Figure 3~4c
Figure 5~6
AI summary
There is provided a method for adaptive bitrate (ABR) adjustments in an IP network before making upshift of ABR level of media streams like video for live Over the Top (OTT) distribution. The invention is based on before upshifting of a current ABR level to a higher ABR level for one or more client devices, probing the network system with a higher bitrate of the data stream provided by e.g. replicating data in the data stream, and monitoring network conditions during probing. Based on the probing it is determined if the available resources in the network are sufficient to sustain an upshift of ABR-level for the client device.