Two types of sound with distinct characteristics are speech and music. As in any other complex system design, any audio compression system design in general aims at high fidelity with low data rates, while keeping the complexity and delay as low as possible. The research in this area relies on multidisciplinary knowledge and techniques much more heavily than any other areas. The audio compression methods rely a lot upon the perspectiveness of the human audio system. These measures may be quite subjective but this is due to the nature of audio systems. 4.ĭelay is critical in a real-time application such as telephony, or teleconferencing. In the real world, perhaps the implementation cost is more important than anything else. The cost is not always reflected in the amount of work because of the increasing computer power and the development of technology. 3.Ĭomplexity means the amount of work required and consequently its cost in order to achieve a certain compression or decompression task. This measure is required due to the restriction of various media such as the access speed to various storage, the capacity of a transmission channel and the playback speed of a certain mechanical device. 2.ĭata rate represents the speed of data transmission via a communication channel, usually measured in bits/second. 1.įidelity measures how close perceptually the reconstructed audio signal sounds in comparison to the original signal. The balance among these factors normally varies depending on the application being supported. Over the years, the most important factors to be considered in audio compression include fidelity, data rate, complexity and delay. Since the sound is a function of time, we also have to take the time into account in addition to the normal complexity consideration. With lossy compression, we have to balance the compression ratio and the quality of the reconstructed sound.

For lossless compression, all we need to measure the compression performance is the compression ratio.

How to compress sound file theory