Event-Based Synchronization for Multi-Device Media Playback
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Solution Overview
Problem
Existing digital media playback systems face challenges in synchronizing media playback across multiple devices over wireless networks, leading to media errors and loss of synchronization, particularly when using broadcast or multicast methods, which can result in uneven media reception among devices in the same listening or viewing space.
Innovation Solution
A method for event-based synchronized multimedia playback, where a media source device transmits common events to multiple destination devices, each with a local clock, allowing for phase and frequency adjustments to synchronize media playback, ensuring that all devices render media in phase and frequency alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If broadcast or multicast methods are used for media transmission over wireless networks, then media can be transmitted to multiple devices simultaneously, but media reception becomes uneven among devices leading to synchronization loss
Solution Approach 1:
The patent implements a feedback mechanism where each destination device reports its local clock state and media reception status back to the source device. The source device uses this feedback to adjust transmission timing and compensate for network variations, ensuring synchronized playback across all devices while maintaining reliable media reception.
Solution Approach 2:
The patent introduces a common time reference or synchronization protocol as an intermediary between the media source and destination devices. This intermediary coordinate system allows all devices to align their playback timing independently, resolving the synchronization issue caused by direct broadcast/multicast transmission over unreliable wireless networks.
2Ease of operation
If local clocks at destination devices are used for playback timing, then each device can operate independently, but phase and frequency differences cause desynchronization
Solution Approach 1:
The patent makes the playback timing dynamic by allowing destination devices to adjust their local clock phase and frequency based on synchronization protocols. Devices can operate independently with local clocks but dynamically adapt their timing to maintain synchronization, combining device independence with precise playback coordination.
Solution Approach 2:
The patent changes the parameters of local clocks at destination devices by adjusting their phase and frequency based on synchronization information from the source device. This allows devices to maintain independence while achieving precise playback synchronization through parameter adaptation rather than fixed timing.
3Measurement precision
If common event-based synchronization is implemented, then playback accuracy improves, but system complexity increases due to clock adjustment mechanisms
Solution Approach 1:
The patent implements self-service synchronization where each destination device autonomously adjusts its local clock based on synchronization events received from the source device. Devices independently calculate and apply their own phase and frequency corrections without requiring complex centralized control, reducing overall system complexity while maintaining high synchronization accuracy.
Data Source
AI summary
A system for event-based synchronized multimedia playback, comprising a media source device and a plurality of destination devices, each destination device comprising a local clock, and a synchronization module on one of the devices. The synchronization module transmits common events, En, each with a unique event number, to each of the plurality of destination devices. Each destination device records time Dxn when event En is received and transmits an acknowledgement message back to the synchronization module comprising time Dxn and event number n. The synchronization module determines phase and frequency differences between clocks of respective destination devices; computes a frequency adjustment to compensate for phase and rate differences; and directs each respective destination device to adjust its clock phase and frequency accordingly. Each destination device adjusts its local clock as directed or may perform a sample rate conversion on sample data in order to enable synchronized media playback.