VoIP audio codecs — Full comparison
The audio codec determines the quality and the bandwidth consumed by each call. WebTic supports the following codecs:
Comparison table
| Codec | Bandwidth | MOS score | Audio bandwidth | Recommended use |
|---|---|---|---|---|
| G.711 PCMU/PCMA | 64 kbps | 4.1 – 4.3 | 3.5 kHz | Universal standard, maximum quality |
| G.729 | 8 – 12 kbps | 3.9 – 4.0 | 3.5 kHz | Low-bandwidth links |
| G.722 | 48 – 56 kbps | 4.1 – 4.3 | 7 kHz (HD) | HD calls, premium quality |
| Opus | 6 – 40 kbps | 4.2 – 4.5 | 20 kHz | WebRTC, adaptive, modern |
Bandwidth calculation
Formula: Simultaneous calls × Codec bandwidth = Total bandwidth
- 100 G.711 calls: 100 × 64 kbps = 6.4 Mbps
- 100 G.729 calls: 100 × 10 kbps = 1 Mbps (84% savings)
- 100 G.722 calls: 100 × 56 kbps = 5.6 Mbps
G.711 — The reference standard
G.711 (PCMU = µ-law for North America, PCMA = A-law for Europe) is the most widespread codec. It does not compress the audio, preserving quality with no processing latency. Recommended for WebTic trunks.
G.729 — For limited connections
Compresses the audio using 20 ms packets. Reduces bandwidth by 87% compared with G.711. Note: a G.729 license may be required on some platforms. Quality is slightly lower (artefacts on fax and DTMF).
G.722 — HD calls
Wideband codec (7 kHz) offering markedly better voice quality. Ideal for contact centers and conferences. Compatible with 3CX, Cisco, Yealink.
Recommended priority order (SDP)
m=audio 5004 RTP/AVP 8 0 18 9 a=rtpmap:8 PCMA/8000 a=rtpmap:0 PCMU/8000 a=rtpmap:18 G729/8000 a=rtpmap:9 G722/8000
Note: Fax must always use G.711 or T.38 — never G.729.
