A New Dimension in Audio Compression and Transmission(Patent Issued)
An audio coding technique for variable, bandwidth-constrained channels such as the Internet must do two things; sound good at low data rates and adapt gracefully to changes in available bandwidth. Professor Les Atlas and Mark Vinton of the Department of Electrical Engineering at the University of Washington have designed an audio coding algorithm that is superior in both counts. It is inherently scalable; the encoded data stream can vary between 11-96 kilobits/second (with original sample frequency at compact disk's 2 stereo channels of 44,100 samples per second) without the need for recoding. This means that variable Internet or wireless channel conditions can be matched without the need for additional computation. Moreover, it is compact; in preliminary subjective tests our algorithm, coded at 32 kilobits/second/channel, outperformed full bandwidth MPEG-1 Layer 3 (MP3) at almost twice the data rate. This new technique is based upon engineering abstractions of a recently discovered new "modulation dimension" in our auditory system. With support by the Office of Naval Research, we are part of a Multi-University Research Initiative: The Center for Acoustics and Auditory Research. The past 4 years of this multi-university collaboration was a major factor in the results we report here. If you have a technical background and/or want to go directly to audio samples of our new techniques' performance, please click here to skip down to our recent publication and samples. If you are interested in research collaborations, please click here to skip to contact information for Prof. Atlas. For licensing information, please click here to skip down to our University's licensing office. Less Technical BackgroundWe are engineering researchers and are thus providing possibilities which will be available to the public 2-5 years from now. While we feel that we've opened up a new technical approach to audio and perhaps video transmission, none of work is expected to have an impact for the public in the next year or two. There still are unanswered research questions and a large amount of engineering and development needed before any of our ideas make it to market. Given that disclaimer, we feel that our research could impact how the public gets their music in the future. Examples of Possible Application's
Our just-published paper is available in the Adobe Acrobat (pdf) format: Audio SamplesPlease beware: These samples of our new process, which have been converted to .wav's, are very large. If you try to download these samples with a telephone modem you will wait for hours!In the near future we hope to be able to share decoders with our research partners. Our decoder will provide for, as expected with our low bit rates, very quick downloads. To load all files below you will need to right-click your mouse on them and "Save Target As..." to some directory on your computer. If you are on a Microsoft Windows platform should then be easy to click on them and listen. These files, which have been losslessly coded as .wav's after passing through our new coder and decoder at the speeds below, are not intended for streaming audio. These samples were deliberately chosen to illustrate the range of quality we see with our CODEC right now for original sample rates of 44,100 samples/sec. For example, the 32 K Dire Straits passage sounds very good, yet the 32 K Tracey Chapman passage has significant artifacts in the artist's voice. We think we know why there still are some artifacts. The principal behind the correction of them is one topic of our research.
For Technical InformationFor more technical information, please contact: Les Atlas atlas@ee.washington.edu Professor and Associate Chair for Research Department of Electrical Engineering University of Washington Box 352500 Seattle, WA 98195-2500 Phone:(206)685-1315For Licensing InformationThere is a patent pending on our new process. For licensing information, please contact: Dana Bostrom bostrom@u.washington.edu Information Products Licensing Software & Copyright Ventures/University of Washington Box 352143/Fluke Hall Phone: 206.616.3451 FAX: 206.616.3322 http://depts.washington.edu/ventures |
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