Quote:
Originally posted by StereoDeluxe
 Memories... Ye I had same problems back in Napster era, it was all ripped by RealJerk Box adding 64K ID3V2 tag (front of MP3 file) for no reason, had to use mp3Trim to clean offset.
Is there way to detect re-encoded files other than ears?
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The only way I know is to analyse the frequency spectrum, there are some pretty convincing spectra graphs for 96k, 128k, 160k, 192k, 224k, 256k & 320k, though the 256 & 320 spectra's are very close, so close that diferent encoders will blur the differences visually, however a 128 to 256 conversion will stand out a mile (or a kilometre for others!) .
Firstly you need to convert the MP3 file into a WAV file, either with DBPowerAmp converter or directly with Sound Forge (versions 4.5 up will read MP3 directly) then apply the FFR analysis filter on a small section of the most active part of the music, I use 30-40 second samples of the most complex parts of the file.
Screen print these spectra for reference purposes, using a known good rip from one of your own CD's as a yardstick, I used the superb Live Nils Lofgren super audio CD for the comparitive tests here.
Ok so its a long tedious job, but if you intend to make a compilation then best to get as many copies of the wanted tracks as you can, select the best versions.
File size, and playing time are dead givaways, as are the odd encodes at other than 44,100 Hz.
Of course, the final result should always be judged by your ear, if it sounds nice to you, then fine.
Some like normalised (all boom and LOUD) personally I prefer to hear dynamic music where the quiet is QUIET and the loud is LOUD..
The normal CD player has a dynamic capability of 96 dB, the complete studio, mixers, recorders, patches etc, usually exceed 75 dB overall, so why compress CD's to a range of 10 - 20 dB?
certainly NOT for Hi-Fi home listening anyway, it may be diferent for you car player, or portable player, but the compression should be in the player NOT on the CD..
I will be posting some typical spectra taken here of 96 to 320k samples as examples, they are in the form of a Word 2000 docthen file so I hope such things are allowed as attachments, if not then it will have to be a sequence of JPG files.
Snark..
