Different Codec Technologies ITUT Codec Kbps Bytes ms
Different Codec Technologies
ITU-T Codec技術比較表 編碼與位 編碼取 元傳輸速 樣大小 率 (Kbps) (Bytes) 編碼 取樣 間隔 (ms) Mean Opinion Score (MOS) 語音 Payload 大小 (Bytes) 語音 Payload 長度 (ms) 每秒封 包數 (pps) Bandwidth Ethernet (Kbps) G. 711 (64 Kbps) 80 10 4. 1 160 20 50 87. 2 G. 723. 1 (5. 3 Kbps) 20 30 3. 8 20 30 34 20. 8 G. 723. 1 (6. 3 Kbps) 24 30 3. 9 24 30 34 21. 9 G. 726 (24 Kbps) 15 5 -- 60 20 50 47. 2 G. 726 (32 Kbps) 20 5 3. 85 80 20 50 55. 2 G. 728 (16 Kbps) 10 5 3. 61 60 30 34 61. 5 G. 729 (8 Kbpps) 10 10 3. 92 20 20 50 31. 2
G. 729 • Annex A ( G. 729. A ) – G. 729 Complex Codec • Annex B ( G. 729. B ) – VAD ( Voice Activity Detection ) – DTX ( Discontinuous Transmission ) – CNG ( Comfort Noise Generation ) • Annex D ( G. 729. D ) – Bit Rate比G. 729低,為 64 bits/frame,頻寬為 6. 4 Kbps • Annex E ( G. 729. E ) – Bit Rate比G. 729更高,為 118 bits/frame,頻寬為 11. 8 Kbps
i. LBC Internet Low Bit Rate Codec Data Frame ( ms ) 20 30 Sampling Frequency ( 8 KHz / 16 bit ) 160 samples 240 samples Fixed bit rate ( Kbit / s ) 15. 2 13. 33 Fixed Frame Size ( Bits per block ) 304 400 Mean Opinion Score ( MOS ) 4. 14 --
參考資料 • List of codecs: http: //en. wikipedia. org/wiki/List_of_codecs
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