No industry standard exists to define “high-definition audio.” However, it generally refers to audio that exceeds the resolution and/or number of channels available on CD. The term also can apply to any audio that exceeds CD’s 16-bit word depth and 44.1-kHz sampling rate. Examples include:
• 20-bit/48-kHz (20/48) audio capability found in many professional audio recording devices
• 24-bit/96-kHz (24/96) audio used on many Blu-ray discs and in the declining DVD-Audio format
• 24-bit/192-kHz (24/192) audio used as the original recording format for many audiophile recordings (and occasionally released on DVD-Audio)
Further, the term can apply to audio with a greater number of channels than the two found on CDs. For example, Dolby Digital offers 5.1 channels, but most audio experts would argue that it cannot be considered high-definition because of the data reduction (or “lossy” compression) it employs.
We define high-definition audio as any audio that exceeds the 16-bit/44.1-kHz CD standard or any audio that exceeds two channels without using lossy compression.