This work presents a novel method for assessing audio authenticity. Assuming that the electric network frequency is embedded in audio signals, the evaluation of audio integrity is carried out by detecting phase discontinuities. This is conducted by using causal and anti-causal filters, in order to avoid the mix of past and future phase information related to the time of analysis. This local phase change is then post-processed and thresholded to obtain the editing times. One remarkable property of the proposed method is its ability to withstand MP3 compression, an audio format widely used in practice. A more accurate evaluation metric is also introduced in this work. For that purpose, the databases used for evaluating the algorithm were automatically labeled indicating the editing times. The procedure to generate the ground truth is presented, as well as a discussion on the proposed metric. The performance of the technique presented promising results when evaluated on digitally edited and original audio signals.
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