Audio Streaming Player Design And Research

The fast advancement of computer technology has made great impact on the traditional analog audio technology. The quality of digital audio has come very close to that of the analog audio recently. Analog audio signal processing (such as mixer, delay, and equalizer) has mainly been done through some special hardware equipments. Because noises tend to be introduced to the original analog signal during the course of transmission and processing, those special equipments tend to be very expensive in order to do a good job on noise reduction and maintaining original audio qualities. Digital audio is different than analog audio in that after the analog signal is converted to digital signal, it can be processed by computer software and/or special signal processing hardware such as DSP processors. High tolerance of interference and fast processing speed of modern DSP processors have made digital audio overcome some of the shortcomings that analog audio possesses. On the other hand, high quality digital audio usually requires large amount of digitized data, which makes data storage and data transmission over the network a major issue. Various data compression methods with different coding algorithms have emerged in order to reduce the amount of data required to store and transmit digital audio signal while minimizing the impact on original audio qualities. This in turn will allow us to create a compact, low cost multimedia digital audio system.Coding algorithms used for audio compression can be categorized as lossless or lossy. Digital audio data are encoded/compressed on the transmit side before transmitting and decoded/decompressed on the receive side. The decompressed audio has the same quality as the original audio if the coding algorithm is lossless or has somewhat lowered quality if the coding algorithm is lossy. Lossy coding is considered only suitable for general purpose applications but not suited for some audio professional applications that require the highest audio quality. This paper presents a stream media player based on an embedded platform. It is designed for both general purpose and audio professional applications. For general purpose applications, MP3 encoding/decoding algorithm is used while for audio professional applications, Ethernet based CobraNet protocol is used. In this paper, we have1. Reviewed the current status of multimedia and digital audio technology, particularly the most commonly used audio file formats and audio compression technologies with pros and cons of each. Discussed commonly used audio network protocols, with particular interest in the features and future prospects of CobraNet technology.2. Comprehensively researched MP3 technology. Fully explained the MP3 principle and implemented MP3 encoding/decoding algorithm on an embedded platform.3. Gave a detailed discussion about the principle of CobraNet and its potential applications.4. Developed a stream media player on an embedded system supporting MP3 coding and CobraNet protocol. Presented detailed hardware and software design and a real application of CobraNet on an embedded system.