Coding of Digital Audio using Psychoacoustic Modeling - Free Final Year Project's

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Aug 9, 2009

Coding of Digital Audio using Psychoacoustic Modeling

This paper present a modified adaptive bit-allocation scheme for coding of audio signals using psychoacoustic modeling. Statistical redundancy reduction (lossless coding) generally gives compression ratios up to 2. We increase this ratio using perceptual irrelevancy removal (lossy coding). In this work MPEG-1 Layer-1 standard for psycho acoustic modeling is used and compression is improved by modifying the bit-allocation scheme, which without using a second stage (lossless) compression, is giving results comparable to that of MP3 (which uses Huffman coding as second stage). You can also Subscribe to FINAL YEAR PROJECT'S by Email for more such projects and seminar.

To increase this ratio further, some of the high frequency sub-bands which contribute less to the signal are removed. Subjective evaluation is the best method to assess the quality of audio signals.

Audio compression is concerned with the efficient transmission of audio data with good quality. The audio data on a compact disc is sampled at 44.1kHz that requires an uncompressed data rate of about 706 kbps for mono with 16 bits/sample. With this data rate audio signals require large memory and bandwidth.

With the present algorithm, high quality can be achieved at bit rates 2 bits/sample (i.e.,90kbps) or above. Sub-band coding is used for mapping the audio signal into the frequency domain. This technique yields certain compression ratios due to its frequency distribution capabilities.



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