Experiments in Audio Compression

Compare for yourself the various tradeoffs between compression algorithm, file size, and audio quality. From my perspective as an audio engineer, only the original CD data and the MPEG-2 versions are of interest. You decide! (Technical data is given at the end of this page).

"Cool"

A cinematic piece with electric and acoustic piano. Strong, adventurous feel. Very melodic with a great groove.

30 second version

60 second version

Full version, 2:40

"Heatseeker"

A mystery-suspense theme with a combination of slow and fast tempos. Has a Latin/Brazilian flavor.

30 second version

60 second version

Full version

"Lunarblue"

A moody mysterious piece. The swing beat has a spacious "film-noir" atmosphere.

30 second version

60 second version

Full version, 3:03

"Distant"

Sad, mysterious piano piece. Reflective and moody feeling.

30 second version

60 second version

"Sahara"

Mystery piece with oboe lead. Pyramids of Egypt!

30 second version

60 second version


All compositions by M. Brewer / G. Russell / G. Kaswell / K. Cooper. This music is Copyright (C) and (P) 1992 by M. Brewer / QCCS Productions.

These pieces are from the CD "QCCS Productions Present Volume VII of Pro-Background Theme Music", titled "Suspense & Mysterious Music & Sound", part number PG PBTM 3-9120.


Technical Information

The AIFF versions of these files are 44.1KHz 16-bit linear (PCM) stereo, copied entirely in the digital domain from the CD to magnetic disk. When played on a suitable set of D/A converters (such as those in an SGI Indigo), the full quality of the CD sound is reproduced. Note that AIFF is not yet an accepted MIME data type and that most machines do not have fast enough sound hardware, so not all Web broswers may be able to play these files.

The AU versions of these files are 8.013KHz 8-bit mulaw monaural format, which provides "telephone quality" sound reproduction. This is presently the "standard" audio format of the Web. I created these files by downsampling the AIFF files using the program SOUNDFILER running on an SGI Irix 5 system. The documentation states that SOUNDFILER uses a high-quality linear phase sampling rate conversion algorithm. These 8-bit versions certainly sound quite good, considering that they are about 1/20th the size of the AIFF versions. Compare for yourself!

The MPEG-2 versions of these files encode the stereo signal and reconstitute to 44.1K samples/second at 16-bits. They use MPEG layer II with the AT&T psycho-acoustic model and no de-emphasis. Several encoding rates are available, at 384Kbits/sec (1:3.7), 256Kbits/sec (1:5.5), 128Kbits/sec (1:11), and 64Kbits/sec (1:22); these bit rates times the playing time determines the final file size. The number given in parenthesis is the file compression ratio. By comparison, the audio bitstream from a CD player is 1,411Kbits/sec. MPEG-2 is the digital audio format in use on the DSS digital satelites, and is one of two formats proposed for the American digital HDTV standard.

This Web server has several high-speed network connections. If your end of the communications link operates at a slow speed, transfers may take a while. It would be best to listen to the 30-second mulaw versions first.

Feed the Musicians

Starving musicians have as much right to eat as starving net hackers. :-) I have purchased the proper license to use this music in my audio/video productions. Your listening to it over the Web constitutes an authorized performance of this music. Storing or re-using it does not. Should you wish to use this music in a production of your own, you will need to acquire a separate license. This is surprisingly inexpensive, about US$60 total for a CD full of music and an unlimited performance license. For more information, please contact the supplier:

QCCS Productions
1350 Chambers Street
Eugene, Oregon 97402
Phone: USA 541-345-0212
Or, visit them on the Web. QCCS Productions operates a "PBTM" Royalty-Free Music Web site.

I have no affiliation with this outfit, other than being a satisfied customer.


Mike Muuss
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