What is Audio Coding?
Audio Coding is the process where audio signals are digitally encoded to make them more compact in representation while preserving as much of the original quality as possible. The primary aim of audio coding is to reduce the amount of data required to store or transmit various types of audio signals while minimizing the apparent loss in quality.
Many applications utilize the functional concept of audio coding, including music and video streaming, digital music players, and mobile devices. Some of the most common audio coding standards are MP3, AAC, and FLAC.
How does Audio Coding Work?
The process of audio coding first encapsulates identifying and removing redundant or irrelevant information from the signal. The aim is to preserve as much of the original audio quality as possible while doing so. This process is also called audio compression.
Inaudible or irrelevant frequencies are often removed at this stage. For example, the frequencies outside the range of human hearing or those masked by louder sounds are eliminated. The leftover audio signal is then segmented into small time intervals called frames. Each frame is then analyzed for common patterns and trends.
After identifying and removing the irrelevant information, the audio signal is represented in a more compact format. One common approach to doing this is using the psychoacoustic model to identify the most important and prominent sounds to human perception and allocate more bits to encoding such sounds. The remaining sounds, which are given lesser precedence, are either encoded with fewer bits or discarded altogether.
The compressed audio signal is further processed and optimized using various advanced techniques like frequency domain transforms, quantization, and entropy coding. The resulting digital audio stream is then stored and can be transmitted and decoded for playback.
Benefits of Audio Coding
- Audio coding compresses signals as much as possible, resulting in smaller file sizes and reduced storage requirements.
- Compressed audio signals are more suitable for efficient transmission over various networks, saving a lot of bandwidth and preventing buffer times during the process.
- Advanced coding standards like AAC and FLAC are good at maintaining high-quality audio signals while compressing them to a significantly smaller size.
- Audio coding is used in various applications, including music streaming and teleconferencing.
Limitations of Audio Coding
- There is some perceptual loss of quality during the audio compression process.
- Audio coding requires a high amount of processing power, especially when used for high-quality or real-time applications.
- Some advanced coding standards like MP3 may still require licensing fees or royalties for use in commercial applications.
- Audio coding standards constantly evolve and may not always be compatible with older platforms, devices, and systems.