PT encoding audio/video clock rate channels
name (A/V) (Hz) (audio)
_______________________________________________________________
0 PCMU A 8000 1 [RFC1890]
1 1016 A 8000 1 [RFC1890]
2 G721 A 8000 1 [RFC1890]
3 GSM A 8000 1 [RFC1890]
4 G723 A 8000 1 [Kumar]
5 DVI4 A 8000 1 [RFC1890]
6 DVI4 A 16000 1 [RFC1890]
7 LPC A 8000 1 [RFC1890]
8 PCMA A 8000 1 [RFC1890]
9 G722 A 8000 1 [RFC1890]
10 L16 A 44100 2 [RFC1890]
11 L16 A 44100 1 [RFC1890]
12 reserved A
13 reserved A
14 MPA A 90000 ?[RFC1890,2250]
15 G728 A 8000 1 [RFC1890]
16 DVI4 A 11025 1 [DiPol]
17 DVI4 A 22050 1 [DiPol]
18--22 unassigned A
23 reserved A
24 reserved V
25 CelB V 90000 [RFC2029]
26 JPEG V 90000 [RFC2435]
27 reserved V
28 nv V 90000 [RFC1890]
29 reserved V
30 reserved V
31 H261 V 90000 [RFC2032]
32 MPV V 90000 [RFC2250]
33 MP2T AV 90000 [RFC2250]
34 H263 V 90000 [Zhu]
35--71 unassigned ?
72--76 reserved for RTCP conflict avoidance [RFC1889]
77--95 unassigned ?
96--127 dynamic ? [RFC1890]
The more common types are 0 (as generated by rat, e.g.)
and 31; furthermore 3 (GSM), 14 (MPA = MPEG-I or -II audio encapsulated as
elementary streams),
32 (MPV = MPEG-I or -II video encapsulated as elementary streams).
The first two can be played with the Real player, as far as I know,
don't know about the others. A short
grep AVP *.sdp | perl -pe 's/.* //' | sort -n | uniq -con 78 cache files gave once:
29 0 (i.e., 29 times PT=0, etc.) 3 3 1 5 7 14 29 31 7 32 2 121
See also:
RTP Transport Protocol for Real-Time Apps Elective 1889 RTP-AV RTP Audio/Video Profile Elective 1890 RTP-CELLB RTP Payload Format of Sun's CellB Elective 2029 RTP-H.261 RTP Payload Format for H.261 Elective 2032 RTP-JPEG RTP Payload Format for JPEG-compressed Elective 2035 --------- RTP Payload Format for H.263 Video ST Elective 2190 RTP-RAD RTP Payload for Redundant Audio Data Elective 2198 RTP-MPEG RTP Payload Format for MPEG1/MPEG2 Elective 2250 RTP-MPEG RTP Payload Format for Bundled MPEG 2343 -------- RTP Payload Format for H.263+ 2429 -------- RTP Payload Format for BT.656 Video Encoding 2431 -------- RTP Payload Format for JPEG-compressed Video 2435 -------- Compressing IP/UDP/RTP Headers 2508See also Henning Schulzrinne's very helpful RTP FAQ.