The payload type (Payload type) in the RTP packet has a column length of 7 bits, so RTP can support 128 types of payload that are not available. This field is used to indicate the type of encoding used by the sound or image, and is determined by the sending side, but of course the receiver has the ability to handle it. If the sender decides to change the encoding mode in the middle of the session or broadcast, the sender can notify the receiving side by this field. The following is a list of some of the currently supported sound and image payload types for RTP.
Payload Number (PT) enconding name Audio/video (A/V) clock rate (HZ) channels (audio)
--------------------------------------------------------------------------------------------------------------- ---------------------------
0 PCMU A 8000 1 [RFC189 0]
1 1016 A 8000 1 [RFC18 90]
2 g.726-32 A 8000 1 [RFC1890 ]
3 GSM A 8000 1 [RFC18 90]
4 g.723 A 8000 1 [Kumar ]
5 DVI4 A 8000 1 [RFC18 90]
6 DVI4 A 16000 1 [RFC18 90]
7 LPC A 8000 1 [RFC1 890]
8 PCMA A 8000 1 [RFC189 0]
9 g.722 A 8000 1 [RFC18 90]
Ten L16 A 44100 2 [RFC18 90]
L16 A 44100 1 [RFC18 90]
QCELP A 8000 1
Reserved A
MPA A 90000 [RFC189 0,2250]
g.728 A 8000 1 [RFC189 0]
DVI4 A 11025 1 [Dipol]
DVI4 A 22050 1 [Dipol]
g.729 A 8000 1
Reserved A
Unassigned A
Unassigned A
Unassigned A
Unassigned A
Dyn gsm-hr A 8000 1
Dyn gsm-efr A 8000 1
Dyn L8 A var. Var.
Dyn RED A
Dyn Vdvi A var. 1
Unassigned V
CelB V 90000 [RFC2 029]
JPEG V 90000 [RFC24 658
Unassigned V
+ NV V 90000 [RFC 1890]
Unassigned V
Unassigned V
H.261 V 90000 [RFC20 32]
MPV V 90000 [RFC22 50]
MP2T AV 90000 [RFC225 0]
H.263 V 90000 [Zhu]
35--71 unassigned?
72--76 reserved for RTCP conflict avoidance [RFC1889]
77--95 unassigned?
96--127 dynamic? [RFC1890]
Dyn BT656 V 90000
Dyn h.263-1998 V 90000
Dyn Mp1s V 90000
Dyn mp2p V 90000
Dyn bmpeg V 90000
The VIDIEO payload type of the H264 can be used in 96.
