I am about music audios.
These can be compressed by different formats with different degree. (I.e. I don't mean the dynamic compression).
After being compressed by a large degree (say 96kbps mp3) the audio may have been saved at a lower "fake" compression degree (say 224 kbps).
Is there a way to estimate how much compressed an audio's content really is (at the above example: telling from the 224 kpbs that the content is not more than about 100 kps)?
The characteristics I calculated so far (freq distr, phase shift etc.) show no difference between the different compression ratio's results.
Now I was thinking from the codec side: Mostly psychoacoustic probably. So... maybe searching for its typical effects: masking, impuls behavior etc.?
Are there any experience, hints, ideas what to calculate?
I can't see any connection to the suggested answer of that other thread. (It's about finding a correlation of a signal to a given pattern (snoring in that case). But my question is completly different: I need to know if there are any characteristics in a signal to tell that is has been compressed by codec and then "blown up" again. I don't have any "master"; neither of the wanted signal, nor of the noise/ snoring. Just an audio of which I want to know if it's as good as its technical specs or if it's worse, as it has been much more compressed before, and unknown by me.)