Proximity-Based Audio Pre-Caching for Low-Latency Playback

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Solution Overview

Problem

Existing media playback systems do not efficiently pre-cache audio content in anticipation of user input, leading to delays in playback when a user approaches a playback device.

Innovation Solution

Incorporating proximity sensors and processors in playback devices to detect user presence and pre-cache audio content before receiving a user command, allowing for immediate playback synchronization across bonded zones or zone groups.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If audio content is pre-cached before user command, then playback latency is reduced, but device complexity increases

Engineering Contradiction:
Improveplayback latencyVSAvoiddevice complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The system performs preliminary actions by detecting user presence through proximity sensors and pre-caching audio content to memory before the user actually issues a playback command. This anticipatory approach eliminates playback latency while the complexity is managed through automated sensor-based triggering rather than manual intervention.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If multiple playback devices are used in bonded zones, then audio coverage and quality are improved, but synchronization difficulty increases

Engineering Contradiction:
Improveaudio playback reliabilityVSAvoidsynchronization complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Multiple playback devices are merged into bonded zones or zone groups where they function as a unified audio system. The devices share memory and coordinate playback through centralized control, achieving improved audio coverage and reliability while the synchronization complexity is abstracted away through the bonding mechanism.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system uses proximity sensors to detect user presence and provides feedback to the playback system, triggering coordinated pre-caching and synchronized playback across all devices in the bonded zone. This feedback loop ensures all devices remain synchronized while responding to user presence.

Inventive Principle:
Principle #23Feedback

3Area of stationary object

If audio content is distributed to multiple devices, then playback coverage is improved, but data transmission time increases

Engineering Contradiction:
Improveplayback coverage areaVSAvoiddata transmission time
Core Design Contradiction:
Area of stationary objectVSLoss of time

Solution Approach 1:

The system distributes audio content to multiple playback devices in advance by detecting user presence and pre-caching content to each device's memory before playback is requested. This preliminary distribution eliminates data transmission delays during actual playback while maintaining wide coverage area.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system creates copies of the audio content and distributes them to multiple playback devices in the bonded zone. Each device stores a local copy in memory, enabling simultaneous playback across multiple devices without requiring real-time data transmission during playback.

Inventive Principle:
Principle #26Copying

Data Source

PatentEP3623958B1Pre-caching of audio content
Publication Date: 2024.04.03 SONOS INC
  • EP3623958B1 patent drawingFigure 1
  • EP3623958B1 patent drawingFigure 2A~2B
  • EP3623958B1 patent drawingFigure 2C~3

AI summary

Embodiments are provided for causing a playback device to pre-cache audio content in anticipation that a user will provide input to cause the playback device to render the audio content. The playback device may be configured to detect, using a proximity sensor on the playback device, movement in relation to the playback device, responsively retrieve audio content by the playback device from a networked audio source, prior to receiving a user command to play the audio content, storing the audio content in memory on the playback device, and cause the playback device to render the audio content upon receiving the user command. The audio content that may be pre-cached may be local audio content stored, on a local memory storage device, network audio content stored on a remote memory storage device, and accessed over a network, or streaming content retrieved over the Internet.