Packet Receiver Dual Decoding for Latency and Quality
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Solution Overview
Problem
Communications networks face challenges in achieving low latency and high media quality for real-time collaboration, as existing protocols like TCP result in long latency due to retransmissions, and FEC adds redundancy that can cause network congestion, making it difficult to balance latency and quality, especially over long distances.
Innovation Solution
A packet receiver with dual decoding chains processes packets within specific time thresholds to produce both low-latency and high-quality media streams, using separate jitter buffers and error correction mechanisms to optimize latency and quality, allowing for efficient handling of both real-time collaboration and media storage or broadcast.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If retransmission is used to guarantee no information loss, then reliability is improved, but latency increases
Solution Approach 1:
The patent segments the media stream into multiple packets with sequential numbering, allowing the receiver to identify and request only specific lost packets through NACK messages rather than retransmitting entire streams. This segmentation enables selective retransmission that maintains reliability while minimizing latency overhead.
Solution Approach 2:
The transmitter pre-sends media packets with embedded sequence numbers and timing information before any loss occurs. The receiver uses these preliminary packets to detect losses and trigger targeted retransmissions, rather than waiting for complete stream failure. This preliminary structuring enables faster recovery.
2Reliability
If FEC redundant information is added to correct errors, then reliability is improved, but network congestion worsens
Solution Approach 1:
Instead of adding FEC redundant data to every packet, the patent creates backup copies of critical packets on-demand when loss is detected. The receiver sends NACK messages requesting specific lost packets, and the transmitter sends exact copies only when needed. This copying approach provides reliability without the continuous bitrate overhead of traditional FEC.
3Reliability
If jitter buffer depth is increased to handle jitter, then reliability is improved, but latency increases
Solution Approach 1:
The patent implements dynamic jitter buffer management where the buffer depth and playout timing are continuously adjusted based on real-time network conditions, packet arrival patterns, and jitter measurements. This dynamic adaptation allows the system to maintain reliability by increasing buffer depth when jitter is high, while minimizing latency when network conditions are stable.
Solution Approach 2:
The system uses feedback from packet arrival timing and sequence number analysis to continuously monitor jitter levels. This feedback drives adaptive adjustments to jitter buffer parameters, enabling the buffer to respond to actual network conditions rather than using fixed depth settings, thereby balancing reliability and latency.
4Adaptability or versatility
If adaptive jitter buffer is used to control buffering, then adaptability is improved, but media quality worsens due to playout rate changes
Solution Approach 1:
The patent segments the adaptive jitter buffer into multiple sub-buffers or zones with different playout rate characteristics. Critical packets are handled with one playout rate while less critical packets use another, allowing adaptive buffering without forcing uniform playout rate changes that would degrade overall media quality.
Solution Approach 2:
Different portions of the jitter buffer are assigned different quality priorities and playout rate adjustments. High-priority packets maintain their original playout timing to preserve media quality, while lower-priority packets absorb timing variations. This local quality differentiation allows adaptability without sacrificing critical media quality attributes.
Data Source
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AI summary
There is provided mechanisms for decoding a media stream. A method is performed by a packet receiver. The method comprises receiving packets. The packets have been transmitted by a packet transmitter. The packets define the media stream and each packet comprises encoded media. The method comprises decoding the encoded media into at least a first decoded version and a second decoded version. For the first decoded version only a subset of the packets decoded for the second decoded version are decoded. The subset includes only those of the packets that are received within a first threshold time delay from having been transmitted by the packet transmitter.