An apparatus comprising one or more processors and at least one non-transitory computer-readable storage medium comprising instructions that, when executed by the one or more processors, cause the apparatus to: perform a first time-frequency analysis of a first block of a received first audio signal according to a first trial audio compression configuration to form a first plurality of spectrograms, wherein performing the first time-frequency analysis of the first block of the received first audio signal to form the first plurality of spectrograms includes windowing the first block of the received first audio signal into a plurality of windows and transforming each of the windows into a corresponding spectrogram, and wherein the first trial audio compression configuration indicates at least one of a time-frequency transform, a window function, or a window length, the first audio signal representing a decompressed second audio signal; perform a second time-frequency analysis of the first block of the received first audio signal according to a second trial audio compression configuration to form a second plurality of spectrograms, wherein performing the second time-frequency analysis of the first block of the received first audio signal to form the second plurality of spectrograms includes windowing the first block of the received first audio signal into a plurality of windows and transforming each of the windows into a corresponding spectrogram, wherein the second trial audio compression configuration indicates at least one of a time-frequency transform, a window function, or a window length; determine a confidence score for the first trial audio compression configuration based on a maximum difference between averages of adjacent spectrograms of the first plurality of spectrograms, and determine a confidence score for the second trial audio compression configuration based on a maximum difference between averages of adjacent spectrograms of the second plurality of spectrograms, wherein a higher maximum difference between averages of adjacent spectrograms is indicative of a higher confidence; select the one of the first and second trial audio compression configurations that has the confidence score which indicates the higher confidence, wherein the selected one of the first and second trial audio compression configurations is identified as a particular audio compression configuration that was used to compress a third audio signal to form the second audio signal; and identify a media source of the second audio signal based on the selected one of the first and second trial audio compression configurations. perform a first time-frequency analysis of a first block of a received first audio signal according to a first trial audio compression configuration to form a first plurality of spectrograms, wherein performing the first time-frequency analysis of the first block of the received first audio signal to form the first plurality of spectrograms includes windowing the first block of the received first audio signal into a plurality of windows and transforming each of the windows into a corresponding spectrogram, and wherein the first trial audio compression configuration indicates at least one of a time-frequency transform, a window function, or a window length, the first audio signal representing a decompressed second audio signal; perform a second time-frequency analysis of the first block of the received first audio signal according to a second trial audio compression configuration to form a second plurality of spectrograms, wherein performing the second time-frequency analysis of the first block of the received first audio signal to form the second plurality of spectrograms includes windowing the first block of the received first audio signal into a plurality of windows and transforming each of the windows into a corresponding spectrogram, wherein the second trial audio compression configuration indicates at least one of a time-frequency transform, a window function, or a window length; determine a confidence score for the first trial audio compression configuration based on a maximum difference between averages of adjacent spectrograms of the first plurality of spectrograms, and determine a confidence score for the second trial audio compression configuration based on a maximum difference between averages of adjacent spectrograms of the second plurality of spectrograms, wherein a higher maximum difference between averages of adjacent spectrograms is indicative of a higher confidence; select the one of the first and second trial audio compression configurations that has the confidence score which indicates the higher confidence, wherein the selected one of the first and second trial audio compression configurations is identified as a particular audio compression configuration that was used to compress a third audio signal to form the second audio signal; and identify a media source of the second audio signal based on the selected one of the first and second trial audio compression configurations.