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Topic: MPEG Audio - Wikipedia bias? (Read 4541 times) previous topic - next topic
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MPEG Audio - Wikipedia bias?

http://en.wikipedia.org/wiki/MPEG-1#Part_3:_Audio

This article seems to have a bias towards MP2, calling MP3 not transparent at any bitrates, and implying AAC cannot handle handclaps. I am not good in writing Wikipedia stuff, but what's the opinion of the guys here? In my opinion saying MP2 is better than MP3 at high bitrates is misleading because in practice MP2 encoders haven't been tuned for at least 10 years and at more than 192 kbps MP3 is transparent apart from problem samples anyways. It also seems to imply MP3 suffers from pre-echo and smearing at any bitrate regardless of the encoder, which is definitely not the cases. In summary, it states some theoretical advantages of MP2 and then claims it is still used in satellite TV and digital radio because of superior quality (which is definitely NOT the case with DAB broadcasts at least).

MPEG Audio - Wikipedia bias?

Reply #1
That section is pretty silly.  I do appreciate that the reference to MP2 being widely used is from 1996.

MPEG Audio - Wikipedia bias?

Reply #2
Indeed. Thanks for bringing this up, I totally forgot about this! Some nonsense or vastly outdated information (emphasis mine):
  • Layer II, Quality: The article says, "MP2 remains a favoured lossy audio coding standard due to its particularly high audio coding performances on important audio material such as castanet, symphonic orchestra, male and female voices and particularly complex and high energy transients (impulses) like percussive sounds: triangle, glockenspiel and audience applause [20]." although such supposedly important audio material isn't mentioned anywhere in that reference [20].
  • Layer II, Quality: MP2 is said "to offer transparent audio compression ... using the earliest reference implementation (more recent encoders should presumably perform even better) ..." but then elaborates on AAC - a much more complicated codec - performing quite badly on applause signals in 1998, making it sound like this were a limitation of the AAC standard (which it clearly isn't, as can be shown with more recent encoders).
  • Layer III/MP3, Technical Details: After describing the block switching to shorter transforms, it is said, "And yet in choosing a fairly small window size to make MP3's temporal response adequate enough to avoid the most serious artifacts, MP3 becomes much less efficient in frequency domain compression of stationary, tonal components." This is purely academic, because who would use short blocks - which are meant for transients - on stationary sounds?
  • In the following paragraph starting with "Being forced to use a hybrid..." it is clear that the author hasn't understood at all how MP3's aliasing cancellation (Edit: actually, it's a reduction) stage works. "... produces frequency domain energy"? "... pushed to the top of the frequency range"?? Of course, MP3's design is bad, but how about the inherent aliasing in MP2 - which cannot be cancelled reduced prior to spectrum quantization - and, consequently, MP2's bad performance on stationary tonal material? That isn't mentioned anywhere.
  • Layer III/MP3, Quality: oh my, every single one of the first 7 sentences (except the 5th one) needs a "Citation needed" mark! It already starts with the totally out-of-context first sentence, "These technical limitations inherently prevent MP3 from providing critically transparent quality at any bitrate". The previous text actually noted some advantages of MP3...
Chris
If I don't reply to your reply, it means I agree with you.

MPEG Audio - Wikipedia bias?

Reply #3
Unless those sections are the pet of someone who has an agenda of defending a decision to roll out DAB rather than DAB+, it should be possible to get things right without much controversy. 

However ... I did a few searches to see if MP2 has been included in listening tests around here.  It could have been some that were posted at soundexperts, but then one has to dig through web.archive.org versions.  I did find one MP2 vs AAC comparison referenced at http://blog.daum.net/echo950/9 , claimed to conform to the ITU BS.1116 standard (the "double-blind triple-stimulus hidden-reference method", I see ...)

MPEG Audio - Wikipedia bias?

Reply #4
Thanks for the answers guys. Is it just me, but why do some people seem to have a preference for obscure/obsolute codecs like ATRAC, ATRAC3, MP2, AC3... while MP3 always gets blamed for all the "evils of lossy compression"? It seems to be a case of "the kids like it, they listen to it on ipods, it must be evil!". Why are some people under the impression that obscure/arcane equipment/formats are somhow superior to everyday ones? I've even seen a thread where someone thinks that the PASC/MP1 coding used on the failed DCC system is somehow superior to "the monstrosity of mp3 style coding", just look http://www.tapeheads.net/showthread.php?t=10001&page=2 .

Every time someone says mp3 or other lossy compression schemes are "just throwing bits out", God kills a kitten...

MPEG Audio - Wikipedia bias?

Reply #5
I would start by going through and deleting the obviously obsolete references.  Anything about the quality of codecs in the 1990s.  Then maybe post a comment in the talk page about sections that need a rewrite and see if anyone is interested in it.  If not, just go through and edit it.

MPEG Audio - Wikipedia bias?

Reply #6
According to WP's change log, the article has tended to be more biased towards layer II through this editing, back in April 2008.

No wonder the contributor's profile is as confusing as his/her contributions.
Listen to the music, not the media it's on.
União e reconstrução