Audio Compression Based on Discrete Cosine Transform, Run Length and High Order Shift
Zainab T. Drweesh · 2014
Audio compression addresses the problem of reducing the amount of data required to represent digital audio. It is used for reducing the redundancy by avoiding the unnecessary duplicate data. In the present work a low complexity and efficient coding scheme based on discrete cosine transform (DCT) is proposed. The proposed system consists of audio normalization, followed by DCT transform, scalar quantization, improved run length encoding and a new high order shift coding. To reduce the effect of quantization noise, which is notable at the low energetic audio segments, a post processing filtering stage is introduced as the final stage of decoding process. The system performance is tested using different audio test samples; the test samples have different size and different in audio signal characteristics. The compression performance is evaluated using peak signal to noise (PSNR) ratio and compression ratio (CR). The test results indicated that the compression performance of the system is promising. The compression ratio is increased with the increase of block size. Also the post processing stage improved the fidelity level of reconstructed audio signal.