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Dial-Up Audio Public Listening Test Opened
CaptainCheese writes "Hydrogenaudio.org's Roberto Amorim just announced the opening of their 32kps multi-format listening test, intended to test the current 'dial-up' quality codecs.
From the Announcement: "The formats featured are Nero Digital Audio (HE-AAC+PS), Ogg Vorbis, WMA9 Std., MP3pro, Real Audio and QDesign Music Codec.
Lame MP3 is being used as low anchor, and a lowpass at 7kHz is being used as high anchor." These codec tests are unusual in that they adhere to ITU-R BS.1116-1. The test is open until July 11th and all are invited to participate. There's more info in the original test discussion, which indicates the originator is interested in 'testing formats working on dial-up streaming bitrates' - the test page notes: 'The real arena where codecs are competing, and most development is going, is at low bitrates.'"
Err, no. No matter how good the line is, sending a well-designed lossily-compressed digital signal over it at the maximum bitrate that can be supported by the line is guaranteed to give you a better result than sending an analogue signal over it. Information theory requires it.
The problem is that "automated comparisons" don't mimic human system responses (the ear, or the eye for video). Take video: the eye would finds grainy VHS tape more pleasing than a digital video that displayed some blocking. The blocked digital video, mathematically, is much closer to the original than the the VHS with its added noise...
These types of psychovisual (or psychoacoustic) responses are what make automated tools almost useless for judging the perceived quality of any lossy encoder. Perceived, that's the key word....it may not be mathematically up to scratch with the original, but if you PERCEIVE it to be as good as the original, thats what matters (this is of course for CD-quality high bitrate tests).