Module header 

The RTP header, its extensions, and the bit masks that encode it. The RTP header and its extensions.

Header is the fixed 12-byte header plus the optional CSRC list and header-extension block. The *_SHIFT/*_MASK constants describe how the flag fields pack into the first two octets, and the *_OFFSET/*_LENGTH constants give the byte positions a caller can patch in place without re-encoding.

Header extensions (RFC 8285) come in two forms, selected by Header::extension_profile: one-byte ids (EXTENSION_PROFILE_ONE_BYTE) or two-byte ids (EXTENSION_PROFILE_TWO_BYTE) when an id above 14 is needed. Use Header::set_extension and Header::get_extension rather than touching Header::extensions directly — they keep Header::extensions_padding and the extension flag consistent, which marshalling depends on.

Structs

Extension

One RTP header extension: an id and its payload bytes.

Header

Header represents an RTP packet header NOTE: PayloadOffset is populated by Marshal/Unmarshal and should not be modified

Constants

CC_MASK

Bit mask of the CSRC count field.

CSRC_LENGTH

Length of each CSRC in bytes.

CSRC_OFFSET

Byte offset of the first CSRC within the header.

EXTENSION_ID_RESERVED

Extension id 15, reserved by the RFC and never assigned.

EXTENSION_MASK

Bit mask of the extension flag once shifted.

EXTENSION_PROFILE_ONE_BYTE

Extension profile 0xBEDE, which selects one-byte header extension ids ([RFC 8285]).

EXTENSION_PROFILE_TWO_BYTE

Extension profile 0x1000, which selects two-byte header extension ids, allowing ids above 14.

EXTENSION_SHIFT

Bit offset of the extension flag.

HEADER_LENGTH

The length of the extension-profile and length fields that precede header extensions.

MARKER_MASK

Bit mask of the marker bit once shifted.

MARKER_SHIFT

Bit offset of the marker bit.

PADDING_MASK

Bit mask of the padding flag once shifted.

PADDING_SHIFT

Bit offset of the padding flag.

PT_MASK

Bit mask of the payload-type field.

SEQ_NUM_LENGTH

Length of the sequence number in bytes.

SEQ_NUM_OFFSET

Byte offset of the sequence number within the header.

SSRC_LENGTH

Length of the SSRC in bytes.

SSRC_OFFSET

Byte offset of the SSRC within the header.

TIMESTAMP_LENGTH

Length of the timestamp in bytes.

TIMESTAMP_OFFSET

Byte offset of the timestamp within the header.

VERSION_MASK

Bit mask of the version field once shifted.

VERSION_SHIFT

Bit offset of the version field in the first header octet.