Wideband audio refers to audio signals sampled at 16 kHz, covering frequencies up to approximately 7 kHz. This provides noticeably better voice quality than narrowband (8 kHz) telephone audio.
Wideband in WebRTC context
The Opus codec used in WebRTC supports multiple bandwidth modes:
- Narrowband: 8 kHz (4 kHz audio bandwidth) – PSTN quality
- Wideband: 16 kHz (8 kHz audio bandwidth) – HD voice quality
- Super-wideband: 32 kHz (16 kHz audio bandwidth) – near-natural quality
- Fullband: 48 kHz (20 kHz audio bandwidth) – full audio spectrum
WebRTC typically operates at fullband by default, but Opus can dynamically switch to lower bandwidths when network conditions (bandwidth, packet loss) require it.
The term “HD voice” used in marketing often refers to wideband audio (16 kHz). WebRTC actually exceeds HD audio quality in most peer-to-peer calls by using fullband Opus.
