Cross-Device Playback Synchronization Using Timestamp Feedback

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Solution Overview

Problem

In distributed hardware systems, asynchronous audio and video playback occurs due to differing sampling rates, post-processing durations, and network jitter during cross-device play, affecting user experience.

Innovation Solution

A synchronous play system and method that involves timestamp exchange and synchronization strategies across multiple devices to align the playback of audio and video streams, using timestamps and delay information to adjust playback rates and synchronize data frames.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If cross-device audio and video streaming is implemented, then distributed service capability is improved, but playback synchronization deteriorates due to different sampling rates and network jitter

Engineering Contradiction:
Improvedistributed service capabilityVSAvoidplayback synchronization
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The system implements a feedback mechanism where the first device sends its playback timestamp to the third device, which forwards it to the second device. The second device compares its own timestamp with the received timestamp and feeds back synchronization status, enabling continuous adjustment of playback timing to maintain synchronization across devices.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The third device acts as an intermediary between the first device and the second device. It receives timestamps from the first device, forwards them to the second device, and facilitates the synchronization process without requiring direct communication between the first and second devices, thus enabling distributed synchronization.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If real-time timestamp exchange is implemented across multiple devices, then playback synchronization is improved, but network communication complexity increases

Engineering Contradiction:
Improveplayback synchronizationVSAvoidnetwork communication complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The third device serves as a communication intermediary that simplifies the network topology. Instead of requiring direct peer-to-peer communication between all devices, the third device mediates timestamp exchange, reducing the number of direct communication channels needed and organizing the communication flow in a structured manner.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system establishes timestamp exchange mechanisms and synchronization protocols in advance before actual playback occurs. Devices prepare their timestamp data structures and communication channels beforehand, allowing for smoother real-time synchronization during playback without ad-hoc complexity.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If timestamp-based synchronization is implemented, then playback timing accuracy is improved, but data processing overhead increases

Engineering Contradiction:
Improveplayback timing accuracyVSAvoiddata processing overhead
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system extracts only the essential timestamp information from complete data packets for synchronization purposes. By separating the timestamp extraction from full data processing, the system achieves precise timing synchronization with minimal processing overhead, as only critical timing data needs to be exchanged and compared.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of exchanging and processing complete data packets between devices, the system uses timestamp copies or metadata that represent the playback state. This allows synchronization decisions to be made based on lightweight timestamp information rather than heavy data packet processing, reducing computational overhead while maintaining accuracy.

Inventive Principle:
Principle #26Copying

Data Source

PatentEP4694146A1Synchronous playing system and method, and electronic device, storage medium and chip system
Publication Date: 2026.02.11 HUAWEI TECH CO LTD
  • EP4694146A1 patent drawingFigure 1
  • EP4694146A1 patent drawingFigure 2
  • EP4694146A1 patent drawingFigure 3

AI summary

This application provides a synchronous play system and method, an electronic device, a storage medium, and a chip system, and relates to the field of distributed hardware technologies, to implement audio-visual synchronization in a cross-device data casting application scenario. The method may be performed based on a device at a play end, and includes: receiving a first timestamp, where the first timestamp represents an actual play time of an mth first data frame on a first device, and m is greater than or equal to 1 and is an integer; reading a second timestamp corresponding to a to-be-played second data frame, where the second timestamp represents a play time sequence of each second data frame in a second data stream; calculating a first play time difference based on at least the first timestamp and the second timestamp; and determining, based on the first play time difference, a synchronous play strategy to be executed for the to-be-played second data frame.