hi all,
On 30-Sep-99 Mike Oliphant wrote:
> Given a .wav file, I want to determine whether the audio data has ever
> been encoded as an MP3 and then decoded back to PCM. Does anyone know if
> there is an easy signature to look for? If I look at the power spectrum,
> will certain frequencies be reliably affected?
interesting question. depending on the encoder there may be some sort of
"signature" in the decoded file.
- old xing encoder you could check for freqs above 16khz (that's an easy one).
- non-modified dist10 ISO encoders you could check for the chunks of pre-echo
and heaps of warbling. (is there an algorithm for pre-echo detection?)
later
mike
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