Audio Data Reduction

is a process used to decrease the amount of data (the file size) needed to store digital audio.

Types of Compression

There are two main categories of data compression:

1. Lossless Compression

This method reduces the file size without discarding any original information.

It works similarly to a .zip file for documents: it optimizes how data is stored, but when you "unzip" the file, the audio is reconstructed in a way that is 100% identical to the original, bit by bit.

• Advantage: Perfect audio quality, identical to the source.

• Disadvantage: The reduction in file size is modest, usually around 2:1 (half the original size).

• Examples: FLAC and ALAC (Apple Lossless).

2. Lossy Compression

This method drastically reduces file size by permanently eliminating parts of the audio that are considered "inaudible" to the human ear. It is based on psychoacoustic principles, such as masking (when a loud sound prevents you from hearing a quieter sound near it).

• Advantage: Very large data reduction, with ratios of 10:1 or 12:1 being common (e.g., a 50 MB file becomes a 5 MB file).

• Disadvantage: The discarded information can never be recovered. At high compression rates, the loss of quality can become audible.

• Examples: MP3, AAC, AC3 (Dolby Digital) and Opus.