Computer Science – 1.2 Multimedia | e-Consult

Uncompressed audio formats, such as WAV and AIFF, store the audio data as a direct representation of the PCM samples. This means that the audio data is stored exactly as it was sampled and quantized, resulting in high audio quality. However, this comes at the cost of large file sizes. The file size is directly proportional to the sampling rate, bit depth, and duration of the audio.

Compressed audio formats, such as MP3, AAC, and Ogg Vorbis, use various compression techniques to reduce the file size. These techniques typically involve removing or approximating audio information that is considered less perceptually significant to the human ear. There are two main types of audio compression:

• Lossy compression: This type of compression permanently removes some audio data to achieve a smaller file size. The audio quality is reduced, but the reduction can be minimized by increasing the compression ratio (at the expense of larger file sizes). Examples include MP3 and AAC.
• Lossless compression: This type of compression reduces the file size without losing any audio data. The original audio can be perfectly reconstructed from the compressed file. Examples include FLAC and ALAC. Lossless compression typically achieves smaller file sizes than uncompressed formats but still larger than lossy formats.

The trade-offs involved in using compression techniques are significant. Lossy compression offers a substantial reduction in file size, making it suitable for applications where storage space is limited (e.g., streaming audio). However, it sacrifices audio quality. Lossless compression preserves audio quality but results in larger file sizes, which can be a disadvantage for storage and bandwidth-constrained applications. The choice of compression technique depends on the specific application requirements and the acceptable level of audio quality.