G.711 : 64Kbps – Mean Opinion Score (MOS) = 4.1
G.729 : 8Kbps – Mean Opinion Score (MOS) = 3.92 (more processing resources required than G.729A)
G.729A : 8Kbps – Mean Opinion Score (MOS) = 3.7 (less processor and DSP intensive)
G.726 : 32Kbps – Mean Opinion Score (MOS) = 3.85
G.728 : 16Kbps – Mean Opinion Score (MOS) = 3.61
ILBC (Internet Low Bitrate Codec) : 15.2Kbps – Mean Opinion Score (MOS) = 4.1
Common Audio Sample Sizes
This is the amount of audio included in each VoIP packet. Larger samples translate to bandwidth savings due to less (overall) overhead required to transport the conversation. However, larger samples also translate to greater codec delay since more time is required to fill a VoIP packet before it is sent on the wire.
At G.711 64Kbps
10 ms = 80 bytes
20 ms = 160 bytes (default sample size)
30 ms = 240 bytes
The following table outlines the CODEC complexity from a processing intensity point of view.