Slashdot Mirror
2nd Multi-Format 128kbps Public Listening Test
technology is sexy writes "Roberto Amorim has launched his latest public listening test evaluating the performance of different audio codecs at 128kbps, among them Apple's AAC implementation (used in iTunes), LAME, Ogg Vorbis fork auTuV, WMA, Musepack and even Sony's Atrac3 format, which is soon to be used in their own music store. Read more on Hydrogenaudio and check out the results of prior tests. As opposed to most evaluations of audio codecs, this is a scientific test adhering to ITU-R BS.1116-1 as much as possible while still allowing everybody to participate."
Because "human auditory capacity" is not fully understood. Sure we can give standard frequency response graph, but most of these codecs take advantage of psycho-accoustic hearing models -- where certain frequencies mask other frequencies in our perception. Since this is a developing field, objective listening tests could really help determine what's working and what's not.
Because "human auditory capacity" is not fully understood. Sure we can give standard frequency response graph, but most of these codecs take advantage of psycho-accoustic hearing models -- where certain frequencies mask other frequencies in our perception. Since this is a developing field, objective listening tests could really help determine what's working and what's not.
From my understanding of MP3 compression and others, the compression protocols take advantage of this frequency masking, so if humans can't hear it, it removes it. It also obviously takes into account frequency ranges of hearing. As a side note, I think it might be neat to be able to compress 30-50% better based on your personal hearing characteristics, but it'd stink if you got old and had to not only wear a hearing aid, but also start collecting MP3's all over again.
Not possible. All you will get is a bunch of WAV-files, you have no way to tell which file belong to which codec.
.ogg vorbis, an mp4 and 3 flacs. If you want to be biased either for or against mp3/oggvorbis/quicktime itunes AAC, you can.
Check the contents of the sampleXX.zip files; you actually get an mp3, an
SCO employee? Check out the bounty
Also what kind of codec bias could you possibly be referring to?
Apparently he doesn't realize that this is a double-blind test - meaning neither the listener nor the tester knows what codec is being presented at any given time.
I'm taking the test now (well, not right now, taking a break) and it's about as scientific as I think you could make a public test taken in the home. Yes, the samples get compressed and then put in easily accessible folders with proper file name extensions, but you never know what you're actually listening to when you're running the testing program. All you have is a source file for comparison, then two buttons marked "1" and "2", one of which is the source again, the other a randomized codec. You never know which of the two buttons is the uncompressed source and you also never know which codec you're hearing. The results are also encrypted, so it's not as if you can just go into the results files and look at what codecs you favor.
I suppose someone who's truly got the Ear of the Gods could listen to the samples outside of the testing program, pick various identifiable traits out of each, then listen for those traits in the testing program and vote up or down whatever codecs he or she chose, but that would be exceedingly difficult and more than a little time-consuming. I can't see how it would be worth it, especially as no single test result is going to skew the overall results to any significant degree.
This is the first time I've ever taken a test like this and I am honestly pretty shocked at how good all of these codecs sound. I am having a really hard time even deciding which is the compressed track most of the time, and I consider myself something of an audiophile. I'm even listening in a fairly controlled environment with a good pair of headphones, at a volume loud enough to hear any background noise clearly but below any clipping whatsoever. I will be surprised if any codec really does significantly better than the others consistently when we see the final test results.