What Does High-Definition Audio (HD Audio) Mean?
High-definition audio (HD audio) refers to a high-bandwidth audio signal used in recorded music. Different software has different standards of high-definition audio, but in most of them the signals are modulated using the pulse width modulation method and sampled at a greater frequency than 44100 Hz, and a depth of more than 16 bits.
High-definition audio is also known as high-resolution audio.
Techopedia Explains High-Definition Audio (HD Audio)
The sound industry makes use of a high-quality audio for better quality music and other sounds. This is especially important where space is not an issue, hence large audio files, with large kBps are preferred. High-definition audio is used in commercial applications where signals are encoded such that there is a minimum loss of information of data and in some cases, the signal is enhanced by sampling at high frequency to increase the quality.
High-definition audio formats include FLAC, ALAC, WAV, AIFF and DSD. However, just because an audio file is stored in these formats, does not necessarily make it high definition.