Tempo Adaptive Backing Track System for Real-Time Audio Synchronization

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Solution Overview

Problem

Conventional music accompaniment apps lack the ability to adapt to a user's tempo and playing style, providing a less immersive experience compared to playing with human musicians.

Innovation Solution

A computer-implemented method and system that estimates user tempo and play position from real-time audio signals, adjusting the backing track to match the user's performance, transitioning smoothly between fuzzy and precise musical elements based on reliability thresholds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the backing track plays at a pre-defined tempo, then the playback is simple and controlled, but the user cannot play along naturally without adjusting to a specific rhythm

Engineering Contradiction:
Improveease of playing alongVSAvoidtempo adaptability
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The system dynamically adjusts the backing track tempo to match the user's playing tempo in real-time. The processor continuously monitors the user's playing speed and automatically synchronizes the backing track accordingly, allowing the user to play naturally without being constrained by a fixed rhythm.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses feedback from the user's playing to adjust the backing track. The processor detects the user's tempo through audio analysis and uses this information to control the playback speed of the backing track, creating an adaptive system that responds to the user's performance.

Inventive Principle:
Principle #23Feedback

2Ease of operation

If the backing track joins in immediately, then the accompaniment starts right away, but the user cannot establish their own tempo and playing style first

Engineering Contradiction:
Improvefreedom to establish playing styleVSAvoidtime before accompaniment starts
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The system allows the user to play a preliminary section without accompaniment, establishing their tempo and playing style first. Only after this initial period does the backing track join in, ensuring the user has already set their own rhythm and the accompaniment can naturally follow.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically controls when the backing track starts based on the user's playing duration. The processor monitors how long the user has been playing and automatically triggers the backing track after a predetermined time threshold, allowing natural tempo establishment before accompaniment begins.

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If the backing track has precise temporal information, then the synchronization is accurate, but the attack points and chord changes are too accentuated for natural playing

Engineering Contradiction:
Improvetemporal precisionVSAvoidnaturalness of playing
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The system applies different temporal characteristics to different parts of the backing track. Less precise, smoother temporal information is used for general accompaniment sections, while more precise temporal information with accentuated attack points is applied only to specific sections where natural playing justifies the precision, creating a balanced and natural overall sound.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4270374B1Method for tempo adaptive backing track
Publication Date: 2026.01.21 OVELIN
  • EP4270374B1 patent drawingFigure 1~2
  • EP4270374B1 patent drawingFigure 3a
  • EP4270374B1 patent drawingFigure 3b

AI summary

A computer-implemented method comprising: providing backing track audio data for one or more songs, wherein each backing track comprises information of at least: tempo of a song, tonal content of the song, wherein the tonal content is synchronized with the backing track audio, optionally, providing musical notation of the tonal content metadata to a user, selecting a song, optionally by the user, receiving a real-time audio signal of the user's performance, estimating parameters, based on the real-time audio signal, comprising at least: playing activity of the user, wherein detecting whether the user is producing any sounding notes with a musical instrument, tempo of the user's playing, and playing position of the user within the selected song, estimating the reliability of the estimated tempo and play position of the user, wherein a value of the reliability represents the probability that the amount of error in the estimated user tempo and play position is sufficiently small, such as smaller than a predefined threshold value, and as soon as the estimated reliability of the estimated user position and tempo is sufficiently high, start playing the backing track at the user position and tempo.