How RepliCheck Works
The following is a description of how RepliCheck® audio verification works.
RepliCheck Audio Identification service helps reduce the risk of replicating pirated audio files. Using Audible Magic’s patented audio fingerprinting technology and proprietary song database, RepliCheck scans a CD and provides the user with a comprehensive report of each track’s song title, artist, releasing label and copyright date. The result is a more accurate, efficient process with reports that prove accountability of your anti-piracy efforts. Here’s how it works:
Install RepliCheck Software on Your PC
We recommend that you use a Personal Computer system with the following minimum requirements:
- Windows 2000
- 500 Mhz Pentium III with 128Mb memory
- Minimum 56kb dialup Internet connection
- Microsoft IE 5.0
You can install the RepliCheck software from an installation CD or we can provide you with an FTP site for download.
Input Audio Files
The RepliCheck service accepts most of the popular DDP mastering formats, audio CDs, WAV files. You can point the software to your PC’s CD ROM drive or to your central network server in order to input audio files.
RepliCheck Uses Audible Magic’s Patented Content Based Audio Identification (CBID) Technology To Take a Fingerprint of Each Song
Every recording has perceptual characteristics that make it unique and identifiable, just like human fingerprints. By measuring these characteristics, Audible Magic can take an unknown segment of audio and pinpoint the specific recording contained in it. Content-based identification (CBID) actually analyzes the acoustic qualities of the audio — it “listens” to the sound. There are a number of techniques that can be used to characterize the perceptual qualities of sound. A typical approach is to analyze the sound’s spectrum. Most sounds contain a mix of frequencies. A spectral analysis measures the loudness of each frequency contained in the sound. A spectrum comprises a large amount of data and would be cumbersome to move over the Internet, so the next step is to extract a “fingerprint” that is small and fast to send, yet preserves the important characteristics needed to make a unique identification of the audio file. Audible Magic researchers found that the most accurate and robust method of taking a fingerprint is to analyze the shape of the spectrum. Audible Magic’s technology uses Mel-filtered Cepstral Coefficients (MFCC) to characterize the shape of a sound.
- Cepstral coefficients provide a way to represent spectral shapes mathematically, based on a Fourier transform function.
- A mel is a unit of measure for the perceived pitch of a tone, rather than its frequency. The ear is sensitive to linear changes in frequency below 1000 Hz and logarithmic changes in frequency above 1000 Hz. Mel-filtering discards any frequencies that a human can’t hear.
Thus a mel-filtered cepstral coefficient describes the shape of a spectrum, adjusted for the way the human ear actually perceives pitch. This patented process results in a digital fingerprint that is uniquely versatile and robust, maintaining accurate identification on files of multiple formats and even of audio that is compressed down to an 8kbps stream.
Audible Magic’s patented CBID technology is based on more than 7 years of scientific, mathematical, and engineering research. A group of former Yamaha engineers developed this groundbreaking method of audio classification and retrieval and received a U.S. patent in July 1999.
Next, The Fingerprint Information is Sent Over the Internet to Audible Magic’s Proprietary Database
The RepliCheck system sends an small audio fingerprint (less than 30KB) over the Internet to Audible Magic’s server. The original audio files do not leave your site.
Audible Magic has made significant investments in building a reference database and search infrastructure to identify millions of copyrighted sound recordings. Working with industry partners, such as Loudeye Technologies and others in the industry, Audible Magic has built and maintains the largest song fingerprint database in the world. The Loudeye catalog by itself includes more than 3.2 million songs on 225,000 CDs, and is updated daily with new releases. This collection includes content from all five major record labels and close to 800 independent labels. Audible Magic is also in the process of fingerprinting content from multiple additional partners including unsigned artists and small independents, a US performing rights organization, and international music publishers.
Audible Magic’s Sophisticated Search Indexing Technology Looks for a Match in the Database
The fingerprint information from the user’s audio file is matched against the Audible Magic’s database to identify each copyrighted track on a CD. It takes less than 15 minutes per CD to identify each track’s song title, performing artist, and album. Audible Magic has developed a proprietary system that is extremely efficient in data and instruction caching. The system detects “no matches” early and eliminates them from the search. This gives RepliCheck the unique ability to speed through a large database while maintaining absolute accuracy.
Information is Sent Back Over the Internet
During the matching process, the Audible Magic Server sends back information to the user’s PC. The user can monitor the system’s progress by viewing a status report on his PC.
The RepliCheck Software Generates Detailed Anti-Piracy Reports
When the process is complete, users can generate a Media Anti-Piracy Report verifying detailed content information for each copyrighted track on a CD.
