Fast method for ENF database build and search

Abstract

The field of digital audio forensics has been driving a sustained research effort in the last decade. Current digital audio authentication frameworks include Electric Network Frequency (ENF) criterion as a must. The ENF-based techniques benefit greatly from the availability of reference databases, which are built using extraction mechanisms that continuously analyze the power line signal. To find the recording time of an ENF-carrying audio, the frequency sequence extracted from the file is matched against a reference database. A database collection method based on spectral analysis needs to trade time resolution for frequency resolution. This tradeoff usually leads to databases with less variance in the frequency series. In this paper we present a method to efficiently build an ENF database, with good time resolution, reduced storage requirements, and a fast two-step search procedure.