Real-Time Multimedia Error Resilience With Adaptive FEC Filtering
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Solution Overview
Problem
Real-time multimedia applications like video conferencing are vulnerable to packet loss due to the unreliable nature of UDP, leading to video mosaic or block, which negatively impacts user experience, and existing error resilience methods are inadequate in handling packet loss without increasing delay or degrading video quality.
Innovation Solution
Implementing a combination of Forward Error Correction (FEC) with adaptive redundancy and packet re-transmission, where FEC is used to protect critical layers with varying redundancy levels and packet re-transmission is limited to minimize delay, along with key frame requests to recover broken sequences, to maintain acceptable video quality under network conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Forward Error Correction (FEC) redundant stream is used to recover lost data packets, then error resilience is improved, but device complexity and bandwidth consumption increase
Solution Approach 1:
The patent applies different FEC redundancy levels to different video layers based on their importance. Critical layers receive higher FEC redundancy protection while less critical layers receive lower protection, optimizing the balance between error resilience and system complexity by applying protection locally where needed rather than uniformly across all data.
2Reliability
If packet re-transmission is used to handle packet loss, then reliability is improved, but delay increases which is unacceptable for real-time applications
Solution Approach 1:
The patent sends FEC redundant packets in advance with the original media packets, so that when packet loss occurs, the receiver can immediately recover lost packets using the pre-sent redundant packets without waiting for re-transmission. This preliminary preparation of error correction data eliminates the delay associated with post-loss re-transmission while maintaining reliability.
3Reliability
If high FEC redundancy is applied to all video data, then error resilience is improved, but video quality and bandwidth efficiency deteriorate
Solution Approach 1:
The patent differentiates between critical and non-critical video layers, applying high FEC redundancy only to critical layers that significantly impact video quality when lost, while applying lower or no FEC redundancy to non-critical layers. This selective approach maintains video quality by protecting only the most important data while avoiding the bandwidth waste and quality degradation that would result from uniform high redundancy across all video data.
Data Source
AI summary
An error resilience method comprising: using a computer, creating and storing, in computer memory, one or more FEC filter tables for use by the FEC filter for selectively forwarding a FEC packet; selectively forwarding a request for the FEC packet through a FEC filter based on the FEC table and a dynamic packet loss level at a receiver; limiting a re-transmission request for a particular packet through the FEC filter based on a number of re-transmission requests for the particular packet; and selectively skipping a key frame request based on a number of key frame requests received from a plurality receiver devices, wherein the method is performed by one or more special-purpose computing devices.