G711G722

G711G722 refers to two ITU-T standardized audio codecs used in telecommunication: G.711, a narrowband PCM codec, and G.722, a wideband codec. Both are common in traditional telephone networks and IP-based voice systems, but they serve different quality and bandwidth needs. G.711 provides a baseline, while G.722 offers higher fidelity at the cost of increased processing.

G.711 encodes speech at 64 kbps using 8 kHz sampling and 8-bit samples. It uses either μ-law (G.711 μ-law) or A-law (G.711 A-law) companding, depending on region. The codec is renowned for simplicity, very low latency, and broad interoperability with the public switched telephone network (PSTN) and many VoIP implementations. Its lack of perceptual compression makes it robust and easy to implement.

G.722 is a wideband codec designed for enhanced voice quality, transmitting audio with bandwidth up to about 7 kHz. It uses 16 kHz sampling and offers three selectable bitrates: 48, 56, or 64 kbps. The encoding employs sub-band ADPCM (SB-ADPCM), delivering clearer and more natural speech than G.711. Increased quality comes with higher computational complexity and slightly higher latency.

Applications and interoperability: Both codecs are widely supported in IP telephony, gateways, and conferencing systems. G.711 is often chosen for compatibility and low latency, especially where PSTN interconnection is important. G.722 is preferred when higher audio quality is desired and network bandwidth and processing capacity permit. The choice depends on device support, network conditions, and deployment goals.