Playout Delay Adjustment for Voice Transmission
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Solution Overview
Problem
In packet-based communication systems, playout delay and packet loss due to network instability pose challenges for real-time voice conversations, making it difficult to maintain reliable and high-quality audio transmission.
Innovation Solution
A playout delay adjustment method using a jitter buffer and Time Scale Modification (TSM) adaptor, which estimates initial and final target playout delays based on network status information and real delay data, and determines adaptation methods such as frame removal, decoding adjustments, or inserting zero frames to minimize delay and error.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If packet retransmission is performed to compensate for packet loss, then packet loss is reduced, but additional delay occurs
Solution Approach 1:
The system performs preliminary actions by pre-calculating and storing compensation values for packet loss and delay in lookup tables before real-time communication occurs. During actual communication, these pre-prepared compensation values are directly applied without calculation, eliminating the need for real-time retransmission and its associated delays.
Solution Approach 2:
The patent introduces intermediary components including a jitter buffer that stores packets temporarily and a playout delay adjustment module that mediates between incoming packets and output timing. These intermediaries smooth out network variations without requiring retransmission, compensating for packet loss through interpolation from adjacent packets.
2Reliability
If playout delay is increased to compensate for jitter, then audio quality is improved, but real-time conversation capability deteriorates
Solution Approach 1:
The system dynamically adjusts the playout delay value based on real-time network conditions. The playout delay is not fixed but adapts continuously according to measured jitter and packet loss rates, allowing the system to optimize between audio quality and real-time responsiveness based on current network state.
Solution Approach 2:
The patent implements feedback mechanisms where the system continuously monitors network status, packet arrival timing, and audio quality metrics. This feedback is used to adjust the playout delay and compensation parameters in real-time, creating a closed-loop control system that balances quality and latency requirements.
3Reliability
If active error adjustment function requests retransmission, then packet error is compensated, but additional delay occurs making real-time conversation difficult
Solution Approach 1:
Instead of requesting expensive and time-consuming retransmissions, the system uses disposable compensation values from lookup tables and interpolates from adjacent packets. These compensation mechanisms are computationally inexpensive and can be applied immediately without waiting for retransmitted packets, preserving real-time conversation capability.
Data Source
AI summary
An electronic apparatus and a playout delay adjustment method thereof are provided. The electronic apparatus includes a target playout delay estimator configured to estimate an initial target playout delay of a current frame by using network status information of a played packet and estimate a final target playout delay of the current frame by updating the estimated initial target playout delay based on real delay information of an unplayed packet, and an adaptation controller configured to determine an adaptation method for adjusting a playout delay of the current frame based on the final target playout delay.