Beat-Matched Audio Crossfading via Partial Frequency Data Analysis

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Solution Overview

Problem

Conventional techniques for beat detection in electronic devices are resource-intensive, making them unsuitable for portable devices that require efficient beat-matched crossfading between audio streams.

Innovation Solution

Analyzing partially decoded compressed audio files to detect beat locations by unpacking them into frequency data, using spectral and time window analyses to identify likely beat frames, and extrapolating these locations for seamless DJ-style crossfading.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional beat detection techniques are used, then beat detection accuracy is improved, but resource consumption increases significantly

Engineering Contradiction:
Improvebeat detection accuracyVSAvoidresource consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The audio file is divided into individual frames, and beat detection is performed on each frame independently using spectral analysis. This segmentation allows the system to process only the necessary portions of the audio data rather than analyzing the entire audio stream, reducing overall resource consumption while maintaining detection accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system performs partial spectral analysis on audio frames to detect beats, rather than performing complete audio decoding and analysis. By applying spectral analysis only to the frequency data that is already unpacked from compressed audio files, the system achieves sufficient beat detection accuracy without the full resource expenditure of conventional techniques.

Inventive Principle:
Principle #16Partial or excessive action

2Measurement precision

If complex beat detection processes are used, then crossfading accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvecrossfading accuracyVSAvoidprocessing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The audio files are pre-decoded and unpacked into frequency data before beat detection is performed. This preliminary action prepares the data in advance, allowing the beat detection algorithm to work with simplified frequency information rather than raw audio streams, thereby reducing processing complexity while maintaining crossfading accuracy.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Frequency data serves as an intermediary representation between the compressed audio files and the beat detection algorithm. By converting the audio to frequency domain data first, the system simplifies the detection process and reduces computational complexity while still achieving accurate beat location identification for precise crossfading.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If full audio decoding is performed for beat detection, then detection accuracy is improved, but processing time increases

Engineering Contradiction:
Improvebeat location accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system extracts only the frequency data that is necessary for beat detection from the compressed audio files, rather than performing complete audio decoding. This extraction approach retrieves only the essential information needed for accurate beat location identification, significantly reducing processing time while maintaining detection precision.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentUS8805693B2Efficient beat-matched crossfading
Publication Date: 2014.08.12 APPLE INC
  • US8805693B2 patent drawing
  • US8805693B2 patent drawing
  • US8805693B2 patent drawing

AI summary

Methods and devices to enable efficient beat-matched, DJ-style crossfading are provided. For example, such a method may involve determining beat locations of a first audio stream and a second audio stream and crossfading the first audio stream and the second audio stream such that the beat locations of the first audio stream are substantially aligned with the beat locations of the second audio stream. The beat locations of the first audio stream or the second audio stream may be determined based at least in part on an analysis of frequency data unpacked from one or more compressed audio files.