this is a very important problem.
As consultant in a legal proceedings, I have an audio file created by voice recorder of Apple. The duration of this file is only 20 seconds long; there is the suspect that the original file was 30 seconds long and that the first 10 second was cutted. I should prove it. My instrument is Sonic Visualizer, due to I can see all frequency graph; and Exiftool, due to I can see all meta of file. Exiftool don’t help me (the meta of a genuine Voice file is the same of a cute file by Quick Time). The question is:
In the frequency audio graph there is a particular characteristic / silent sort period / device “signature” / something else at the beginning of a voice file, which is present in all file produced by the recorder of iPhone?
Thank you very much!