source count (SC): 5 bits
The number of SSRC/CSRC identifiers included in this BYE packet.
A count value of zero is valid, but useless.
If a BYE packet is received by a mixer, the mixer forwards the BYE
packet with the SSRC/CSRC identifier(s) unchanged. If a mixer shuts
down, it should send a BYE packet listing all contributing sources it
handles, as well as its own SSRC identifier. Optionally, the BYE
packet may include an 8-bit octet count followed by that many octets
of text indicating the reason for leaving, e.g., "camera malfunction"
or "RTP loop detected". The string has the same encoding as that
described for SDES. If the string fills the packet to the next 32-bit
boundary, the string is not null terminated. If not, the BYE packet
is padded with null octets.
Schulzrinne, et al Standards Track [Page 37]
RFC 1889 RTP January 1996
6.6 APP: Application-defined RTCP packet
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|V=2|P| subtype | PT=APP=204 | length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SSRC/CSRC |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| name (ASCII) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| application-dependent data ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The APP packet is intended for experimental use as new applications
and new features are developed, without requiring packet type value
registration. APP packets with unrecognized names should be ignored.
After testing and if wider use is justified, it is recommended that
each APP packet be redefined without the subtype and name fields and
registered with the Internet Assigned Numbers Authority using an RTCP
packet type.
version (V), padding (P), length:
As described for the SR packet (see Section 6.3.1).
subtype: 5 bits
May be used as a subtype to allow a set of APP packets to be
defined under one unique name, or for any application-dependent
data.
packet type (PT): 8 bits
Contains the constant 204 to identify this as an RTCP APP
packet.
