Neowin.net

Thanks WinOScentral for this rather nice pointer to an interesting article over at PC World concering audio formats and the codecs used to store our music on our computers..

Many people complain that compressed audio doesn't sound as good as CD audio. To verify that claim, we subjected a group of typical listeners to blind tests to see whether they could tell the difference between music from CDs and compressed versions of the songs in a variety of file formats. We also asked the testers to rate the compressed versions on a quality scale.

From each of five pieces of music, we ripped a 30-second clip from a CD to a .wav file. The five music selections were an acoustic version of Daughter by Pearl Jam, Radioactivity by Kraftwerk, a cellos-only version of Wherever I May Roam by Apocalyptica, a live version of Time by Pink Floyd, and O Fortuna from Carl Orff's Carmina Burana.

We compressed each clip to a variety of bit rates using Windows Media Encoder for the WMA format, Real Jukebox Plus for the RealAudio format, MusicMatch Jukebox Plus for the MP3 format, and RealJukebox Plus with the Dolby AAC plug-in for Dolby's AAC format.

We then played back both the original files and the uncompressed versions to 30 testers (mainly PC World staff, but we also got representatives from Dolby laboratories, Microsoft, and Real Networks to participate). We asked them to identify the compressed versions. We used a double-blind testing methodology in which each tester was given three files to listen to, called A, B, and C: The A file was the .Wav file ripped directly from the CD. The other two were either the .Wav file or a compressed version.

View: PC World's Review - Compressed Audio vs. CDs: Can You Tell the Difference?

To screen passengers, aviation authorities are considering biometric scanners that check identities against criminal records and terrorist watch lists, Mr Charles said.

"Biometrics attempts to keep the wrong people off airplanes, instead of trying to keep bombs and weapons off airplanes," Mr Charles said.

Face-recognition systems show promise in matching terrorists' mug shots — garnered from files of the FBI, CIA or Interpol — to faces roaming airport crowds. One such system was installed in June at Iceland's Keflavik International Airport. Others are under consideration in the US.

Biometric systems are already in use by Customs and the INS. The INS' system uses hand-geometry scanning kiosks to permit entry to registered travellers. And Customs' new border-crossing cards for Mexicans store fingerprint data.

Charles said fingerprint identity checks may also appear at check-in counters, where travellers' names and thumbprints are checked against watch lists and criminal records.

But without a US criminal record — or at least a photo and some background information — a terrorist will not be intercepted by a biometric security system.

"What if he's not in anybody's database? He'll walk right through," said Robert Mannal, of KPMG's information risk management office.

Security measures being proposed for aircraft themselves take this reality into consideration.

In Cleveland, ADR Investigation and Protection Corp is discussing installing closed circuit television systems on the jetliners of three airlines, said company president Lex Rosenbaum. He would not name the carriers.

The systems would allow pilots to keep an eye on the passengers while sending streaming video to ground stations, where it could be monitored or stored for a later investigation, Mr Rosenbaum said.

Experts stressed, however, that high-tech systems are merely aids for security personnel whose duties and powers also stand to be augmented.

"Most of this is feel-good stuff," Ms Vincent said. "It avoids taking the hard measures you need to do the job."

But protecting airports and planes will ultimately fail to make Americans safe from terrorism, said William Head, a professor at Indiana University and hijacking researcher.

Terrorists, by their nature, prefer neglected targets where chances for success are greatest, he said.

"You get displacement," Mr Head said. "The terrorist says, 'OK, I can't get on a plane. I'm going to get on a bus."