What is payload type in SDP?
What is payload type in SDP?
The format parameters of the RTP payload are typically communicated between transmission endpoints with the Session Description Protocol (SDP), but other protocols, such as the Extensible Messaging and Presence Protocol (XMPP) may be used. …
What is Rtpmap in SDP?
In the case of dynamic payload numbers (payload numbers between 96 and 127), there has to be an explicit mapping specified in the SDP body, using the a=rtpmap attribute. lists three static payload numbers: 0, 8, and 18.
What is codec payload?
Codec Payload Size 711, G. 726 codec types are unique, in that they can use dynamic payload types in the 96-127 range, but for backward compatibility they will default to use static payload types if a dynamic payload type is not provided using NPDI TLVs.
What is dynamic payload?
A dynamic payload type is one where the mapping is defined during session setup, often using SIP or RTSP. For example, you might find that the SDP in the SIP/RTSP message includes: m=audio 49000 RTP/AVP 121 a=rtpmap:121 G7221/16000 meaning that the G.722.1 codec is assigned payload type 121.
What is SDP used for in RFC 2833?
SDP is used to describe the voice stream (e.g. G.729) and it’s also used to inform the recipient that RFC 2833 is available. Specifically, it uses something called telephone-event. Here is an example of an SDP media description that you might see in the body of an Invite message. Note the format of “0 – 16.”
What is the payload type number in RFC 2833?
The local device sends the payload type number to use for 2833 telephone event packets using a SDP or H.245 Terminal Capability Set (TCS), which tells the other side what payload type number to use when sending the named event packets to the local device.
What is the purpose of RFC 2833 DTMF interworking?
RFC 2833 defines the format of NTE RTP packets used to transport DTMF digits, hookflash, and other telephony events between two peer endpoints. With the NTE method, the endpoints perform per-call negotiation of the DTMF transfer method. They also negotiate to determine the payload type value for the NTE RTP packets.
Which is the default payload type for RTP event?
RTP Event (RFC 2833) uses dynamic payload type ranging from 96 to 127 (I think default is 96). It’s opposed to some other codecs which use static payload type like G.711Mu (payload 0) and G.711A (payload 8). Moreover both the end points during SDP negotiation can use different payload type for DTMF.