Implementation of low delay, low bit-rate audio compression for wireless digital audio system | |
| Author | Jessada Karnjana |
| Call Number | AIT Thesis no.ME-06-07 |
| Subject(s) | Psychoacoustics Auditory perception |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Microelectronics, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. ME-06-07 |
| Abstract | The question to increase the compression rate while the reproduction quality to be still acceptable leads to the term of perceptual audio compression. Audio perceptual coding based on a psychoacoustic model which using to eliminate the irrelevant information. Psychoacoustic model is a mathematical model of human perceptual of sound. The goal of model is to develop functions that are related to hearing sensations of human auditory system. For real-time applications, e.g. wireless speaker, headphones, or internet telephony, these applications do not require high audio quality but require low coding delay. To achieve this fashion, I designed a system with low complexity to reduce the computational times but the quality does not much different from audio CD. I used MDCT filter banks as subband coding. The advantage of MDCT is its perfected reconstruction. For quantizing. I compare the coding performance both full-range and narrow-range. A full-range quantization gave poor dequantized signals compare to narrow-range quantization. But full-range is acceptable for a low bit-rate requirement. Adding Huffman coding after quantization improves compression ratio less than 5%. It depends on the nature of data to compress. Huffman coding is useless in the case of less identical data. Thus I designed the system to check the identical data before perform Huffman coding. This codec gave the average compression ratio about 2.71: I or 62.5%. The number of bits per sample reduced to 5.99 bits per sample b'om 16 hits per sample |
| Year | 2006 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. ME-06-07 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| Department | Department of Industrial Systems Engineering (DISE) |
| Academic Program/FoS | Microelectronics (ME) |
| Chairperson(s) | Afzulpurkar, Nitin V.;Pasin Israsena; |
| Examination Committee(s) | Chumnarn Punyasai; |
| Scholarship Donor(s) | Thailand Graduate Institute of Science and Technology; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2006 |