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.'"

Re:Is this a double-blind test?

[TommydCat]

On this site there is a useful little utility [pcabx.com] written by Arny Krugar to let you do your own DBT testing at any bitrate with any codec you want.

It does take a bit of preperation, but the results are legit. Not really suited for large organized polls, but fine to see your personal tastes and to understand exactly what a double-blind test is and how it works and why it is the only valid way to scientifically test.

Re:hm... the days of dialup

[eeg3]

Satellite is available anywhere there is uninhibited view of the sky, which is most places that don't have cable or DSL. However, satellite is expensive to set up... $500 installation fee from DirecTV last I checked.

Secondly, dial-up is not that bad, and it's definitely not as bad as your exaggeration. It's not comparable to broadband, but it's not unbarable. To further speed up dialup browsing, one should use a web cache, which is very helpful.

Interesting results

[sploo22]

I just took the test with sample 9, one of the speech ones, and it's amazing how much variability there is in the various codecs. One of them was so good I could only reliably hear the difference after a dozen repeated listenings, and another sounded like a cellphone in a tunnel. I'll be interested to see the results in a week or so.

Re:Phone line are shit

[julesh]

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.

Re:What's the point?

[bcombee]

Actually, low bitrates will be more important in the near future, as more people use streaming audio over PCS data services. For example, I listen to low-bitrate streams over Shoutcast several times a week on my PalmOne Treo 600, and 32Kbps streams much better than 64Kbps, while higher than that just isn't feasible on Sprint's PCS network. While this isn't as much of an issue for home users, mobile devices on relatively low-speed networks are going to be big.

Re:Results may be flawed

[izx]

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).

Re:hm... the days of dialup

[YankeeInExile]

Spot-beam satellite (i.e. DirecTV's offering, the British company whose name escapes me) is not available anywhere there is an uninhibited view of the sky. If you look at the contour maps for those products, you will see they are pretty tightly focused on their target market. I suspect it's even more of a problem on the uplink side -- those systems are running with really tight link budgets, and I don't think you're going to get an acceptable uplink BER if your antenna is 10dB off boresite.

While there are VSAT products that are available virtually anywhere, they are orders of magnitude more expensive. (For E1 speed in, say, Nigeria, figure $45K US per month, plus hardware costs in the several-kilobuck range.)

There is also an Intelsat data product, that last time I checked was about USD $7 per minute for DS0. A subrate option was available (9.6k) for about USD 2 per minute.

Re:Slashdot Low Bitrate Ethnocentrism

[Anonymous Coward]

It's not even available in some places in Sydney (and other major Australian cities), because of the short-sightendness of our telecommunication companies in the 1980s and 1990s. They decided it would save money to multiplex the phone lines using a system called "pair gain". Now, anybody who has had this done to them can't get DSL.

A technician from the telco told me that we will get DSL in my area "some time after hell freezes over".