Audio Watermarking with Masked Frequency Codes for Media Tracking
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Solution Overview
Problem
Current media monitoring technologies face challenges in accurately identifying and tracking audio streams across various media platforms, such as television and radio, due to limitations in embedding and detecting imperceptible codes within audio signals, which affects audience measurement and content metadata collection.
Innovation Solution
The implementation of an audio watermarking system that encodes information into audio signals using a process involving a sampler, masking evaluator, code frequency selector, and code synthesizer to embed codes inaudible to listeners, and a decoder that extracts these codes using Fourier transformation and normalization techniques for detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If codes are embedded into audio signals for media monitoring, then media identification and tracking capability is improved, but the complexity of the embedding and detection system increases
Solution Approach 1:
The audio signal processing is divided into distinct functional modules: a sampler that segments audio into discrete samples, a masking evaluator that analyzes perceptual masking opportunities, a code frequency selector that chooses optimal embedding frequencies, and a code synthesizer that generates the watermark signal. This segmentation allows each component to be optimized independently while maintaining overall system reliability for media identification.
2Object-affected harmful factors
If codes are made imperceptible to listeners, then audio quality is preserved, but the difficulty of detecting and measuring the codes increases
Solution Approach 1:
The system dynamically adjusts embedding parameters including code frequency selection based on the spectral characteristics of the audio signal, modulation depth to operate below the threshold of human perception, and temporal distribution of code elements. The masking evaluator analyzes the audio signal's perceptual masking properties and modifies code parameters accordingly, ensuring imperceptibility while maintaining detectability through specialized correlation-based detection algorithms.
3Adaptability or versatility
If codes are embedded across various media platforms, then versatility of monitoring system is improved, but the complexity of detecting codes in different audio environments increases
Solution Approach 1:
The embedding system generates codes with universal characteristics that can be detected across different media platforms including television, radio, and digital audio. The code structure uses robust modulation schemes and redundancy that maintain detectability despite variations in transmission channels, playback devices, and audio processing. The detection system employs correlation-based methods that are platform-agnostic, allowing the same detector to operate across diverse audio environments without requiring platform-specific customization.
Data Source
AI summary
Encoding and decoding methods and apparatus as described. In one example, a method of embedding auxiliary information into an audio signal includes sampling the audio signal to create an audio block; receiving a code; determining frequency components that will be used to represent the code, wherein different sets of frequency components represent respectively different information and wherein one frequency component from each set of frequency components is located in a code band and there are multiple code bands and spacing between adjacent code bands is equal to or less than the spacing between adjacent frequency components of each code band; determining amplitudes of the frequency components that will be used to represent the information, wherein the amplitudes of the frequency components are determined by a masking ability of the audio block; synthesizing the frequency components that will be used to represent the information, wherein the frequency components are synthesized with the determined amplitudes; and combining the synthesized code frequency components with the audio block.