Audio Sync via Latency Compensation and Timing Instructions

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Solution Overview

Problem

Existing techniques for synchronizing audio playback across multiple electronic devices are inaccurate due to unaccounted timing offsets, latency buffering, and re-connecting issues, leading to out-of-sync audio experiences.

Innovation Solution

Implementing a system where one device acts as a master, using near field communication (NFC) and wireless connections like Wi-Fi Direct to detect and connect with slave devices, calculate network latency, and synchronize audio playback by sending timing instructions based on system clock offsets, allowing for manual or automatic adjustments to ensure synchronized audio across multiple devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If existing techniques are used for syncing audio playback across multiple speakers, then the setup process is simple, but the audio playback becomes out-of-sync due to unaccounted timing offsets and latency buffering

Engineering Contradiction:

Improvesetup processVSAvoidtiming synchronization

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The system performs preliminary latency measurements and timing offset calculations before audio playback begins. The master device sends test signals to slave devices and measures the round-trip time to establish baseline latency values, which are then used to pre-adjust playback timing instructions.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors playback synchronization by having slave devices report their actual playback timing back to the master device. The master device uses this feedback to dynamically adjust timing instructions and compensate for drift or variable latency conditions during playback.

Inventive Principle:

Principle #23Feedback

2Device complexity

If timing offsets and latency buffering are not accounted for, then the system operates with minimal processing, but audio playback from multiple devices becomes out-of-sync

Engineering Contradiction:

Improveprocessing operationsVSAvoidaudio synchronization

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts playback timing parameters based on measured latency conditions. The master device calculates corrected timing instructions that compensate for network latency, device processing delays, and buffer characteristics, transforming the raw timing data into synchronized playback commands.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If the system calculates and adjusts for network latency and system clock offsets, then audio playback synchronization improves, but the setup and operation complexity increases

Engineering Contradiction:

Improveaudio synchronizationVSAvoidsynchronization operations

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

Each slave device autonomously measures its own latency to the master device and calculates its required timing adjustment. The devices self-configure their playback schedules without requiring manual intervention or complex centralized configuration, reducing operational complexity while maintaining precision.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The master device acts as an intermediary that coordinates timing between devices. It sends reference timing signals and receives latency measurements from slave devices, then consolidates this information to generate corrected timing instructions that reconcile clock offsets and network latency across the entire system.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Device complexity

If re-connecting attempts are not handled adequately, then the system operates with fewer protocols, but audio playback synchronization reliability deteriorates

Engineering Contradiction:

Improveprotocol handlingVSAvoidaudio playback continuity

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The system establishes latency measurements and timing corrections before audio playback begins and before potential connection issues arise. This preliminary configuration allows the system to quickly resume synchronized playback after reconnection without requiring complex real-time adjustment protocols.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements heartbeat signals and playback status reporting that allow devices to detect connection losses and trigger reconnection procedures. When reconnection occurs, the feedback mechanism ensures that timing synchronization is re-established by having slave devices re-measure latency and receive updated timing instructions from the master device.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS20230403663A1Systems and methods for syncronizing multiple electronic devices

Publication Date: 2023.12.14 GOOGLE TECHNOLOGY HOLDINGS LLC

AI summary

Embodiments are provided for syncing multiple electronic devices for collective audio playback. According to certain aspects, a master device connects (218) to a slave device via a wireless connection. The master device calculates (224) a network latency via a series of network latency pings with the slave device and sends (225) the network latency to the slave device. Further, the master devices sends (232) a portion of an audio file as well as a timing instruction including a system time to the slave device. The master device initiates (234) playback of the portion of the audio file and the slave devices initiates (236) playback of the portion of the audio file according to the timing instruction and a calculated system clock offset value.