Payload type | Name | Type | No. of channels | Clock rate(Hz) | Frame size(ms) | Default packet size(ms) | Description | References |
---|---|---|---|---|---|---|---|---|
dynamic (or profile) | AMR | audio | (various) | 8000 | 20 | Adaptive Multi-Rate audio | RFC 4867 | |
0 | PCMU | audio | 1 | 8000 | any | 20 | ITU-T G.711 PCM µ-Law audio 64 kbit/s | RFC 3551 |
8 | PCMA | audio | 1 | 8000 | any | 20 | ITU-T G.711 PCM A-Law audio 64 kbit/s | RFC 3551 |
9 | G722 | audio | 1 | 8000 | any | 20 | ITU-T G.722 audio 64 kbit/s | RFC 3551 - Page 14 |
4 | G723 | audio | 1 | 8000 | 30 | 30 | ITU-T G.723.1 audio | RFC 3551 |
dynamic | G726-16 | audio | 1 | 8000 | any | 20 | ITU-T G.726 audio 16 kbit/s | RFC 3551 |
dynamic | G726-24 | audio | 1 | 8000 | any | 20 | ITU-T G.726 audio 24 kbit/s | RFC 3551 |
dynamic | G726-32 | audio | 1 | 8000 | any | 20 | ITU-T G.726 audio 32 kbit/s | RFC 3551 |
dynamic | G726-40 | audio | 1 | 8000 | any | 20 | ITU-T G.726 audio 40 kbit/s | RFC 3551 |
3 | GSM | audio | 1 | 8000 | 20 | 20 | European GSM Full Rate audio 13 kbit/s (GSM 06.10) | RFC 3551 |
31 | H261 | video | 90000 | ITU-T H.261 video | RFC 4587 | |||
34 | H263 | video | 90000 | H.263 video, first version (1996) | RFC 3551, RFC 2190 | |||
dynamic | H263-1998 | video | 90000 | H.263 video, second version (1998) | RFC 3551, RFC 4629, RFC 2190 | |||
dynamic | H263-2000 | video | 90000 | H.263 video, third version (2000) | RFC 4629 | |||
7 | LPC | audio | 1 | 8000 | any | 20 | Experimental Linear Predictive Coding audio 5.6 kbit/s | RFC 3551 |
dynamic (or profile) | opus | audio | 1, 2 | 48000 | 2.5–60 | 20 | Opus) audio | RFC 7587 |
dynamic (or profile) | speex | audio | 1 | 8000, 16000, 32000 | 20 | Speex audio | RFC 5574 | |
dynamic | raw | video | 90000 | Uncompressed Video | RFC 4175 | |||
dynamic | VP8 | video | 90000 | VP8 video | draft-ietf-payload-vp8 | |||
dynamic | RED | audio | Redundant Audio Data | RFC 2198 |
带宽计算公式:
带宽=包长度×每秒包数
=包长度×(1/打包周期)
=(Ethernet头+IP头+UDP头+RTP头+有效载荷)×(1/打包周期)
=(208bit +160bit+64bit+96bit +有效载荷)×(1/打包周期)
=(528bit+(打包周期(秒)×每秒的比特数))×(1/打包周期)
=( 528 / 打包周期 ) + 每秒比特数
按照上面的计算公式:
G711:20ms打包,带宽为 ( 528/20 + 64) Kbit/s=90.4 Kbit/s
G729:20ms打包,带宽为 ( 528/20 + 8 ) Kbit/s= 34.4 Kbit/s
G723:5.3k,30ms打包,带宽为 ( 528/30 + 5.3 ) Kbit/s=22.9 Kbit/s
业界一般按照下表提供的IP网带宽系数和以太网带宽系数来设计网络带宽:
编解码技术 | 压缩速率(Kbps) | 打包周期(ms) | IP网带宽系数 | 以太网带宽系数 |
---|---|---|---|---|
G.711 a/u | 64 | 20 | 1.25 | 1.41 |
G.729 a/b | 8 | 20 | 0.38 | 0.54 |
G.723.1(5.3kbit/s) | 5.3 | 30 | 0.27 | 0.37 |
G.723.1(6.3Kbit/s) | 6.3 | 30 | 0.25 | 0.36 |
H.263(384Kbit/s) | ≈384 | 10 | 6 | 6.2 |
注:采用某种编码方式时,用64K乘以相应的带宽系数就可以得出其实际占用的带宽。当然如果是中继接口,还需要考虑信令占据一定的带宽,一般按照2.5%来计算。