Is there a tool to compare songs or virtual CDs to check if they come from different sources or not?

For example the second show from Oakland (1969.11.09) is in sixty plus variations available. I doubt that so many tapers where out there when bootleggig was in its fledgling stages.

Most of my boots are digital only and I wonder if it's possible to group the copies of copies (of copies) with the final goal to find out out what is the source and it's family of derived copies.

Without a technical tool I see no chance to do that.

My background is photography and there is some kind of "fingerprinting" for 1:1 exact copies of images, similar images etc. I assume there is a similar technology for audio.

Thank you in advance for any hints.

dd

Waveforms and spectral analysis, for example in Audacity or Adobe Audition, can be used to "see" differences. I also use them, when I find some funny versions, like a longer Miss You (version I) or a longer Sheep Dip Blues. You can see very often, where parts have been spliced together, to make faked versions. Also higher reel to reel generations can be seen very well in spectral analysis. The red marks (Audacity) are getting lower and lower with every new analogue copy.



Edited 4 time(s). Last edit at 2021-04-18 13:45 by BlueTurns2Grey.

This might help: FLAC Fingerprint. I prefer to listen and pick a preferred version to keep.

If you do not want to dig deep with waveforms and spectral analysis - the first stage would be to check files using EAC (Exact Audio Copy) and foobar.

EAC will return a log file that with TOC (table of content for CD), peak levels and checksum. TOC and checksum can be different for different CDs. TOC is dependent on LBR (laser beam recorder) that was used for glass master preparation and specific details of tracks separation (so called cue points). I.e. the source is the same but LBR can introduce (instrumental pre-set) a couple of null samples in the beginning of the CD, the signal can be 180 degree phase inverted, somebody can set separation between tracks a bit different (or cut applause) etc. Checksum depends on the drives that were used for ripping and the ripping procedure (i.e. the way null samples were accounted). However peak level will give you a hint if the CD was produced from the same master. I.e. peak level reflects maximum volume for each track. If these values are the same (while TOC is a bit different) - most probably the same master tape (or clone of a master tape) was used. Well, it will not work if the rip was not made using accurate rip settings for the drive (i.e. normalization for peak level was used, read offset for the drive was not set properly, etc.). This happens quite often. Especially if torrent site rules are not strict with respect to ripping procedure or program that is different form EAC was used.

The other option is foobar2000 with Dynamic Range Meter plugin. It also returns TOC, peak levels and dynamic range information. Thus, comparing peaks and DR one can assume if the same original digital content was used.

These methods, however, work well only with official material. Like comparing CDs that were produced at different plants in different parts of the world. For example, most of the 2002 ABKCO remasters are digital 1:1 clones no matter where they were pressed - in Germany, Japan or USA.

The problem with bootlegs is - each company can tweak/remaster the material on their own. Thus, it is almost impossible to track down all the details. It is possible that something close to the original master tape was issued (let's say) in 1989 by company A (old-good times, primitive digital technologies). Afterwards it was remastered by company B in 1999 and re-issued by C, D and E a bit later. Afterwards somebody (even guys from this forum) made another remaster/matrix using alternative source for IORR BST section in 2005. And this one was used in 2006 by company F with clones by companies G and H (H adds a bit more compression, for example). You can group these remasters but you will not know for sure all the details.

Thanks for your suggestions. I appreciate it.
dd