Network Music Session Delay Measurement Apparatus
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Solution Overview
Problem
Conventional delay measurement systems for network music sessions fail to accurately determine the total delay time from input to output of an audio signal across communication networks like the Internet, as they do not account for delays other than network round trip time and require high-precision clock synchronization, which is unreliable in variable network environments.
Innovation Solution
A delay measurement system that includes components for retrieving input delay, transmission delay, reception buffering delay, and output delay on both terminals, allowing for the calculation of total input/output delay without high-precision clock synchronization, using measurement packets and adjustable buffer sizes to monitor and update delay times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If network round trip time RTT is measured to figure out one-way network delay time, then network delay time can be determined, but delays other than network (terminal input delay, output delay, reception buffer delay) are not included, resulting in inaccurate total delay measurement
Solution Approach 1:
The patent segments the total delay measurement into four distinct components: terminal input delay (Ti), network transmission delay (Tn), reception buffer delay (Tbf), and terminal output delay (To). Each component is measured and retrieved separately by dedicated modules, then summed to obtain the total delay. This segmentation allows accurate measurement of all delay sources while maintaining system manageability through modular design.
Solution Approach 2:
The patent introduces delay retrieval portions as intermediary components that obtain delay values from respective sources (terminal processing, network transmission, buffer storage) and aggregate them. These intermediaries facilitate the combination of separately measured delay components without requiring complex direct measurement of the entire system, thus improving measurement accuracy while controlling complexity.
2Measurement precision
If high precision clock synchronization is used to figure out delay time difference between terminals, then delay time can be calculated, but the scheme cannot be applied to communication systems with low reliability due to inconstant delays
Solution Approach 1:
The patent applies preliminary action by having each terminal retrieve and store its own input delay (Ti) and output delay (To) characteristics before actual audio transmission. The reception buffer delay (Tbf) is also determined in advance based on buffer size configuration. These pre-retrieved delay values are then used in the total delay calculation, eliminating the need for complex real-time clock synchronization and making the system reliable in variable network conditions.
Solution Approach 2:
Each terminal independently retrieves its own delay characteristics (input delay Ti and output delay To) without relying on the other terminal's clock synchronization. The system uses self-service measurement where terminals determine their own processing delays and exchange this information, making the measurement process independent of clock synchronization reliability and suitable for unstable network environments.
3Adaptability or versatility
If buffer size of reception buffer is made variable to adapt to network conditions, then adaptability is improved, but delay time calculation becomes more complex
Solution Approach 1:
The patent implements dynamics by making the reception buffer size variable rather than fixed. The buffer size can be adjusted based on network conditions and user requirements, with the delay retrieval portion automatically retrieving the corresponding buffer delay (Tbf) value. This dynamic configuration allows the system to adapt to varying network conditions while the automated retrieval process manages the complexity of delay calculation.
Data Source
AI summary
In this system, a terminal A retrieves terminal's input delay time Tia from input of an audio signal to start of transmission of the audio signal, transmission delay time Tn from the start of transmission of the audio signal to reception of the audio signal by a partner terminal B, partner's reception buffering delay time Tbfb from reception of the audio signal to output of the audio signal by a reception buffer portion BFb of the partner terminal B, and partner's output delay time Tob from input of the audio signal to output of the audio signal by an audio reproduction portion DRob of the partner terminal B. The terminal A then sums up these delay times to determine input/output delay time Ttab from the input of the audio signal by the terminal A to the output of the audio signal by the audio reproduction portion DRob of the partner terminal B.