A Study on ENF Discontinuity Detection Techniques

Electrical network frequency (ENF) is known to be useful for audio authentication. In a digital archive system, error concealment of the audio files are sometimes required. Firstly, assuming that traditional recordings were produced by AC-powered devices, the ENF is coupled into the recorded signals. Secondly, assuming that damaging and editing produce similar data error patterns, the ENF phase discontinuities exist in a damaged audio file. To detect phase discontinuity, three phase tracking methods are studied and discussed: DFT over sampling, band pass filtering, and a combined approach. The basic concept of the three methods is to achieve high-precision phase analysis. The cost is the computation complexity. Due to the special properties of ENF, it is likely to reduce the complexity by a certain trade-off design. We then describe the future research directions at the end of this paper.