Editing RTP Control Protocol (section)

==Packet header==
{{APHD|start|title=RTCP packet header{{Ref RFC|3550}}}}
{{APHD|0|bits1=2|field1=Version|field2=P|bits3=5|field3=RC|bits4=8|field4=PT|bits5=16|field5=Length}}
{{APHD|4|bits1=32|field1=SSRC Identifier}}
{{APHD|end}}
;{{APHD|def|name=Version|length=2 bits|text=Identifies the version of RTP, which is the same in RTCP packets as in RTP data packets. The version defined by this specification is two (2).}}
;{{APHD|def|name=Padding|short=P|length=1 bit|text=Indicates if there are extra padding bytes at the end of the RTP packet. Padding may be used to fill up a block of certain size, for example as required by an encryption algorithm. The last byte of the padding contains the number of padding bytes that were added (including itself).}}
;{{APHD|def|name=Reception Report Count|short=RC|length=5 bits|text=The number of reception report blocks contained in this packet. A value of zero is valid.}}
;{{APHD|def|name=Packet Type|short=PT|length=8 bits|text=Contains a constant to identify RTCP packet type.}}
;{{APHD|def|name=Length|length=16 bits|text=Indicates the length of this RTCP packet (including the header itself) in 32-bit units minus one.}}
;{{APHD|def|name=SSRC Identifier|length=32 bits|text=''Synchronization Source Identifier'' uniquely identifies the source of a stream.}}

Note that multiple reports can be concatenated into a single compound RTCP packet, each with its own packet header.