http://www.pczone.com.tw/vbb3/thread/16/100142/29/#post1049651

編碼標準 Bit rate(Kbps) MOS G.711  64       4.3 G.726  32       4.0 G.723  6.3       3.8 G.728  16       3.9 G.729  8        4.0 GSM HR 5.6       3.5 GSM EFR 12.2      4.0

*MOS(Mean Opinion Score) 5-Excellent 4-Good == 收費品質要求(根據ITU-T Recommendation P.800) 3-Fair 2-Poor 1-Bad