In this case it seems that the question is referring to fidelity - the file's similarity to the original uncompressed audio after it was sampled and mastered bu

In this case it seems that the question is referring to fidelity - the file's similarity to the original uncompressed audio after it was sampled and mastered but before the lossy compression. I would think that you could use something like RMSE [1] to measure this, but I'm not experienced in this kind of thing. [1] https://en.wikipedia.org/wiki/Root_mean_square_deviation https://en.wikipedia.org/wiki/Root_mean_square_deviation