EdiTracker: audio authentication analysis
Software plug-in for audio authenticity analysis.
- Six authentication methods
- Training and support
Part of the SIS II
EdiTracker is a unique plug-in for SIS II and is designed to provide audio authenticity analysis. Paired with SIS II functionality it significantly increases its capabilities in terms of identifying modified, edited or doctored audio.
EditTracker provides automation of all operations related to the search and analysis of suspicious areas of phonogram fragments and calculation of a recorder's technical specifications. It makes possible to visualize all the steps of research and gives you an opportunity to generate text reports of the entire research or each kind of analysis separately, which also may be used in the court as a part of expert's or specialist's report.
EdiTracker speeds up the process of your forensic analysis and increases the reliability of expert conclusion.
"The advent of digital audio made it far easier to tamper with recorded evidence. But it also gave investigators a host of new and powerful tools.
Improvements in forensic-audio software have given the field a big boost. Allen (Stuart Allen, forensic audio expert), for example, used a software package called EdiTracker 2.0 to dissect his doctored recording. First he played the audio file for the audience and displayed its spectrogram on a projection screen. Then he punched a key on his laptop.
Within seconds, EdiTracker had scanned the file and flagged a bunch of "feature discontinuities" - unexpected bumps in frequency and amplitude, miniscule gaps and other unusual events. They're undetectable to the naked ear, but could indicate tampering."
Wired Magazine, Audio Forensics Experts Reveal (Some) Secrets by Alexander Gelfand
Calculation of a recorder’s parameters
Each analog recorder has its own characteristics such as frequency response, total harmonic distortions, detonation, amplitude modulation, and speed. EdiTracker automatically assesses these characteristics using a test signal. Finding a mismatch between the recorder’s parameters and characteristics of a signal that was allegedly recorded with a given unit can be an indication of tampering.
Finding the traces of previous digital processing
Digital processing of analog signals requires a specific sample rate. During the digitizing process of an analog signal, a phenomenon called aliasing occurs. To avoid this phenomenon, the vast majority of analog-to-digital and digital-to-analog converters use anti-aliasing filters. EdiTracker automatically searches for traces of the filter, which may be reminiscent of analog nature of the original audio or previous digitizing at a lower sampling rate.
Finding the traces of tampering by the harmonic’s phase shift
EdiTracker automatically scans the audio for technical narrow-band signals which normally come from an electrical network (ENF), batteries, nearby electrical appliances etc and estimates their phase continuity. Unjustified phase break may be interpreted as a possible editing point and should be subject to further auditory and instrumental analysis.
Background noise scanning
Background scanning procedure is the detection of the dramatic change in the spectrum unnoticeable on the waveform related to possible audio editing.
EdiTracker automatically scans the integrity of background noises marking the abrupt change of noise level.
EdiTracker provides an access to the step-by-step instructions for the auditory-linguistic analysis and to the extended list of indicators of a recording authenticity breaches making it possible to create a detailed list of linguistic features of tampering and further use them in a text report.
|Supported file formats||all formats in case proper codecs are installed (*.WAV, *.MP3, *.WMA, *.AVI)|
|Minimum duration of signal||10 seconds|
|Methods of processing||6|