2.2.11 RTCP Profile Specific Extension
The RTCP profile specific extension is appended to the RTCP SR or RR reports and is used to carry additional information not contained in the RTCP SR or RR reports. It is a block of data that immediately follows the RTCP SR or RR report packets. As with the rest of the RTP and RTCP fields, all integer fields on profile specific extensions are in network byte order, with the most significant byte first.
The common header for such extensions is defined as follows:
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2 |
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Extension Info (variable) |
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Type (2 bytes): The extension type.
Length (2 bytes): The extension length in bytes, including this header.
Extension info (variable): Dependent on the extension type.
Any profile extension that is not recognized MUST be ignored by using the length field to skip the Extension Info. Other Type values are not used by any servers and are reserved for future use.
The number of profile extensions in one RTCP SR or RR report MUST be less than or equal to 20.<21>
The extensions defined are described in the next sections.