Distributed Playback Timing to Synchronize Multi-Device Audio
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Solution Overview
Problem
Existing playback systems face challenges in synchronizing multiple networked devices playing audio content from different sources due to asynchronous clocking rates and non-deterministic network delays, leading to timing loops and desynchronization issues.
Innovation Solution
A group of playback devices adjusts playback timing based on clock timing information received from other devices, decoupling playback timing from clock timing generation, and using any device in the network to provide clock timing for synchronous playback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If each playback device uses its own local clock for timing, then device independence and operational autonomy are maintained, but synchronization accuracy deteriorates due to asynchronous clocking rates and non-deterministic network delays
Solution Approach 1:
The patent introduces a timing intermediary layer that decouples playback timing from clock timing generation. Instead of devices directly using their local clocks for playback timing, a separate timing mechanism mediates between clock sources and playback operations, allowing independent clocking while maintaining synchronized playback through shared timing references.
Solution Approach 2:
The patent segments the timing function into two independent components: clock timing generation and playback timing. This segmentation allows each device to maintain its own clock (preserving independence) while using a shared playback timing reference (achieving synchronization), thereby resolving the contradiction between device autonomy and sync accuracy.
2Adaptability or versatility
If playback timing is coupled with local clock timing, then device autonomy is maintained, but system-wide synchronization deteriorates due to clock drift and rate differences
Solution Approach 1:
The timing intermediary decouples the relationship between local clocks and playback timing, allowing devices to maintain autonomy in clock selection while ensuring reliable synchronization through a common timing reference that mediates between diverse clock sources.
Solution Approach 2:
The patent creates a universal playback timing reference that can accommodate multiple different clock sources with varying rates and drift characteristics. This universal timing mechanism serves all devices in the network, enabling them to maintain their own autonomous clocks while achieving reliable synchronized playback through the common reference.
3Measurement precision
If a centralized master clock is implemented, then synchronization accuracy improves, but system complexity and single point of failure risks increase
Solution Approach 1:
The patent segments the centralized timing authority into distributed components, where timing reference generation is separated from clock timing generation. Multiple devices can serve as timing references without requiring a complex hierarchical master-slave architecture, reducing system complexity while maintaining synchronization accuracy.
4Adaptability or versatility
If devices source audio content from different sources, then content versatility improves, but timing coordination deteriorates due to multiple timing references
Solution Approach 1:
The timing intermediary acts as a mediator between diverse audio content sources and the playback timing system. It provides a unified timing reference that coordinates playback across multiple devices sourcing content from different sources, ensuring timing coordination reliability regardless of content source diversity.
Data Source
AI summary
Disclosed herein are playback devices, groups of playback devices, and methods of operating playback devices and groupings thereof to cause the playback devices in a group of playback devices to play audio content together in synchrony based on playback timing and clock timing, where the audio content and playback timing and the clock timing for use with playing the audio content according to the clock timing are provided by different playback devices in the group of playback devices.