I have always admired Daniel Barenboim, both as a pianist and as a conductor — and not just because years ago, from pictures on disk covers, we looked strikingly alike, see e.g.  which could almost be me at that time (Then I went to see him in concert and realized that he was a good 15 centimeters shorter; the pictures were only head-and-shoulders. Since that time the difference of our physical appearances has considerably increased, not compensated, regrettably, by any decrease of the difference of our musical abilities.)
Nowadays you can find lots of good music, an unbelievable quantity in fact, on YouTube. Like this excellent performance of Beethoven’s Emperor Concerto  by Barenboim with a Danish orchestra.
If you go to that page and expand the “about” tab an interesting story unfolds. If I parse it right (I have no direct information) it is a record of a discussion between the person who uploaded the video and the YouTube copyright police. It seems YouTube initially rejected the upload on the basis that it violated no fewer than three different copyrights, all apparently for recordings of the concerto: one by the Berlin Philharmonic (pianist not named), one by Arthur Rubinstein (orchestra not named), and one by Ivan Szekely (orchestra not named). The uploader contested these copyright claims, pointing out that the performers are different in all four cases. It took a little more than a month before YouTube accepted the explanation and released the video on 22 April 2012.
Since the page clearly listed the performers’ names and contained a full video, the initial copyright complaints must have been made on the basis of the audio track alone. Further, the detection must have been automatic, as it is hard to imagine that either YouTube or the copyright owners employ a full staff of music experts to listen all day to recordings on the web and, once in a while, write an email of the form “I just heard something at http://musicsite.somewhere that sounds suspiciously close to bars 37-52 of what I remember from the `Adagio un poco mosso’ in the 1964 Rubinstein performance, or possibly his 1975 performance, of Beethoven’s Emperor“. (The conductor in Rubinstein’s 1975 recording, by the way, is… Daniel Barenboim.) Almost certainly, the check is done by a program which scours the Web for clones.
It seems, then, that the algorithm used by YouTube or whoever runs these checks can, reasonably enough, detect that a recording is from a certain piece of music, but — now the real scandal — cannot distinguish between Rubinstein and Barenboim.
If this understanding is correct one would like to think that some more research can solve the problem. That would assume that humans can always distinguish performers. On French radio there used to be a famous program, the “Tribune of Record Critics“, where for several hours on every Sunday the moderator would play excerpts of a given piece in various interpretations, and the highly opinionated star experts on the panel would praise some to the sky and excoriate others (“This Karajan guy — does he even know what music is about?“). One day, probably an April 1st, they broadcast a parody of themselves, pretending to fight over renditions of Beethoven’s The Ruins of Athens overture while all were actually the same recording being played again and again. After that I always wondered whether in normal instances of the program the technicians were not tempted once in a while to switch recordings to fool the experts. (The version of the program that runs today, which is much less fun, relies on blind tasting, if I may call it that way.) Presumably no professional listener would ever confuse the playing of Barenboim (the pianist) with that of Rubinstein. Presumably… and yet reading about the very recent Joyce Batto scandal , in which a clever fraudster tricked the whole profession for a decade about more than a hundred recordings, is disturbing.
If my understanding of the situation regarding the Barenboim video is correct, then it remarkable that any classical music recordings can appear at all on YouTube without triggering constant claims of copyright infringement; specifically, any multiple recordings of the same piece. In classical music, interpretation is crucial, and one never tires of comparing performances of the same piece by different artists, with differences that can be subtle at times and striking at others. Otherwise, why would we go hear Mahler’s 9th or see Cosi Fan Tutte after having been there, done that so many times? And now we can perform even more comparisons without leaving home, just by browsing YouTube. Try for example Schumann’s Papillons by Arrau, Kempf, Argerich and — my absolute favorite for many years — Richter. Perhaps a reader with expertise on the topic can tell us about the current state of plagiarism detection for music: how finely can it detect genuine differences of interpretation, without being fooled by simple tricks as were used in the Batto case?
Still. To confuse Barenboim with Rubinstein!
References and notes
 A photograph of the young Barenboim: see here.
 Video recording of performance of Beethoven’s 5th piano concert by Daniel Barenboim and Det kongelige kapel conducted by Michael Schønvandt on the occasion of the Sonning Prize award, 2009, uploaded to YouTube by “mugge62” and available here.
 Wikipedia entry on Joyce Hatto and the Barrington-Coupe fraud, here.