Quote:
Originally posted by Mazer
Snark is right about the frequency cutoff, but his process is more work than simply listening to the forgeries. I'm sure a simple utility could be written that would scan the first 10 seconds of an MP3 for the lowpass cutoff and compare that number to the default cutoff for the MP3's bitrate, and maybe even look for quantization noise that shouldn't be there.
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Different musical styles, instrumentations and mixing styles all produce such different frequency spectrums that I am rather skeptical of any spectral data being enough to spot fakes without proper reference data. To make reliable quality tests you would actually need a high-quality reference rip from a trusted source to compare its spectrum to that of the suspect rip. But if you have a trusted source who is willing to deliver you reference quality rips, why would you download anything from the suspicious guys in the first place...
I see two good practical approaches to handling the quality/fake problem. One is to publish the unique content signatures (hash numbers) for the rips that a trusted person or group has checked and verified to be good - something that our skillful Morphia members have already demonstrated to work in practice.
The other approach is to allow peers to form trust chains and groups among themselves with their p2p client and use these trusted channels to establish more quality-conscious distribution chains within the community. Not all people care for quality and there will probably always be some low-quality and faked stuff in circulation in the open p2p networks. But even then both above approaches would help a quality-conscious collector to keep the bad stuff out of his/her own library.
- tg
