RTCP is the Real-Time Control Protocol
This page hosts a formal specification of rtcp network payload (single udp packet) using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.
All parsing code for Python generated by Kaitai Struct depends on the Python runtime library. You have to install it before you can parse data.
The Python runtime library can be installed from PyPI:
python3 -m pip install kaitaistructParse a local file and get structure in memory:
data = RtcpPayload.from_file("path/to/local/file.bin")
Or parse structure from a bytes:
from kaitaistruct import KaitaiStream, BytesIO
raw = b"\x00\x01\x02..."
data = RtcpPayload(KaitaiStream(BytesIO(raw)))
After that, one can get various attributes from the structure by invoking getter methods like:
data.rtcp_packets # => get rtcp packets
# This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild
import kaitaistruct
from kaitaistruct import KaitaiStruct, KaitaiStream, BytesIO
from enum import Enum
if getattr(kaitaistruct, 'API_VERSION', (0, 9)) < (0, 9):
raise Exception("Incompatible Kaitai Struct Python API: 0.9 or later is required, but you have %s" % (kaitaistruct.__version__))
class RtcpPayload(KaitaiStruct):
"""RTCP is the Real-Time Control Protocol.
.. seealso::
Source - https://www.rfc-editor.org/rfc/rfc3550
"""
class PayloadType(Enum):
fir = 192
nack = 193
ij = 195
sr = 200
rr = 201
sdes = 202
bye = 203
app = 204
rtpfb = 205
psfb = 206
xr = 207
avb = 208
rsi = 209
class SdesSubtype(Enum):
pad = 0
cname = 1
name = 2
email = 3
phone = 4
loc = 5
tool = 6
note = 7
priv = 8
class PsfbSubtype(Enum):
pli = 1
sli = 2
rpsi = 3
fir = 4
tstr = 5
tstn = 6
vbcm = 7
afb = 15
class RtpfbSubtype(Enum):
nack = 1
tmmbr = 3
tmmbn = 4
rrr = 5
transport_feedback = 15
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.rtcp_packets = []
i = 0
while not self._io.is_eof():
self.rtcp_packets.append(RtcpPayload.RtcpPacket(self._io, self, self._root))
i += 1
class PsfbAfbRembPacket(KaitaiStruct):
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.num_ssrc = self._io.read_u1()
self.br_exp = self._io.read_bits_int_be(6)
self.br_mantissa = self._io.read_bits_int_be(18)
self._io.align_to_byte()
self.ssrc_list = []
for i in range(self.num_ssrc):
self.ssrc_list.append(self._io.read_u4be())
@property
def max_total_bitrate(self):
if hasattr(self, '_m_max_total_bitrate'):
return self._m_max_total_bitrate
self._m_max_total_bitrate = (self.br_mantissa * (1 << self.br_exp))
return getattr(self, '_m_max_total_bitrate', None)
class SrPacket(KaitaiStruct):
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.ssrc = self._io.read_u4be()
self.ntp_msw = self._io.read_u4be()
self.ntp_lsw = self._io.read_u4be()
self.rtp_timestamp = self._io.read_u4be()
self.sender_packet_count = self._io.read_u4be()
self.sender_octet_count = self._io.read_u4be()
self.report_block = []
for i in range(self._parent.subtype):
self.report_block.append(RtcpPayload.ReportBlock(self._io, self, self._root))
@property
def ntp(self):
if hasattr(self, '_m_ntp'):
return self._m_ntp
self._m_ntp = ((self.ntp_msw << 32) & self.ntp_lsw)
return getattr(self, '_m_ntp', None)
class RrPacket(KaitaiStruct):
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.ssrc = self._io.read_u4be()
self.report_block = []
for i in range(self._parent.subtype):
self.report_block.append(RtcpPayload.ReportBlock(self._io, self, self._root))
class RtcpPacket(KaitaiStruct):
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.version = self._io.read_bits_int_be(2)
self.padding = self._io.read_bits_int_be(1) != 0
self.subtype = self._io.read_bits_int_be(5)
self._io.align_to_byte()
self.payload_type = KaitaiStream.resolve_enum(RtcpPayload.PayloadType, self._io.read_u1())
self.length = self._io.read_u2be()
_on = self.payload_type
if _on == RtcpPayload.PayloadType.sr:
self._raw_body = self._io.read_bytes((4 * self.length))
_io__raw_body = KaitaiStream(BytesIO(self._raw_body))
self.body = RtcpPayload.SrPacket(_io__raw_body, self, self._root)
elif _on == RtcpPayload.PayloadType.psfb:
self._raw_body = self._io.read_bytes((4 * self.length))
_io__raw_body = KaitaiStream(BytesIO(self._raw_body))
self.body = RtcpPayload.PsfbPacket(_io__raw_body, self, self._root)
elif _on == RtcpPayload.PayloadType.rr:
self._raw_body = self._io.read_bytes((4 * self.length))
_io__raw_body = KaitaiStream(BytesIO(self._raw_body))
self.body = RtcpPayload.RrPacket(_io__raw_body, self, self._root)
elif _on == RtcpPayload.PayloadType.rtpfb:
self._raw_body = self._io.read_bytes((4 * self.length))
_io__raw_body = KaitaiStream(BytesIO(self._raw_body))
self.body = RtcpPayload.RtpfbPacket(_io__raw_body, self, self._root)
elif _on == RtcpPayload.PayloadType.sdes:
self._raw_body = self._io.read_bytes((4 * self.length))
_io__raw_body = KaitaiStream(BytesIO(self._raw_body))
self.body = RtcpPayload.SdesPacket(_io__raw_body, self, self._root)
else:
self.body = self._io.read_bytes((4 * self.length))
class SdesTlv(KaitaiStruct):
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.type = KaitaiStream.resolve_enum(RtcpPayload.SdesSubtype, self._io.read_u1())
if self.type != RtcpPayload.SdesSubtype.pad:
self.length = self._io.read_u1()
if self.type != RtcpPayload.SdesSubtype.pad:
self.value = self._io.read_bytes(self.length)
class ReportBlock(KaitaiStruct):
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.ssrc_source = self._io.read_u4be()
self.lost_val = self._io.read_u1()
self.highest_seq_num_received = self._io.read_u4be()
self.interarrival_jitter = self._io.read_u4be()
self.lsr = self._io.read_u4be()
self.dlsr = self._io.read_u4be()
@property
def fraction_lost(self):
if hasattr(self, '_m_fraction_lost'):
return self._m_fraction_lost
self._m_fraction_lost = (self.lost_val >> 24)
return getattr(self, '_m_fraction_lost', None)
@property
def cumulative_packets_lost(self):
if hasattr(self, '_m_cumulative_packets_lost'):
return self._m_cumulative_packets_lost
self._m_cumulative_packets_lost = (self.lost_val & 16777215)
return getattr(self, '_m_cumulative_packets_lost', None)
class RtpfbTransportFeedbackPacket(KaitaiStruct):
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.base_sequence_number = self._io.read_u2be()
self.packet_status_count = self._io.read_u2be()
self.b4 = self._io.read_u4be()
self.remaining = self._io.read_bytes_full()
@property
def reference_time(self):
if hasattr(self, '_m_reference_time'):
return self._m_reference_time
self._m_reference_time = (self.b4 >> 8)
return getattr(self, '_m_reference_time', None)
@property
def fb_pkt_count(self):
if hasattr(self, '_m_fb_pkt_count'):
return self._m_fb_pkt_count
self._m_fb_pkt_count = (self.b4 & 255)
return getattr(self, '_m_fb_pkt_count', None)
@property
def packet_status(self):
if hasattr(self, '_m_packet_status'):
return self._m_packet_status
self._m_packet_status = self._io.read_bytes(0)
return getattr(self, '_m_packet_status', None)
@property
def recv_delta(self):
if hasattr(self, '_m_recv_delta'):
return self._m_recv_delta
self._m_recv_delta = self._io.read_bytes(0)
return getattr(self, '_m_recv_delta', None)
class PsfbPacket(KaitaiStruct):
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.ssrc = self._io.read_u4be()
self.ssrc_media_source = self._io.read_u4be()
_on = self.fmt
if _on == RtcpPayload.PsfbSubtype.afb:
self._raw_fci_block = self._io.read_bytes_full()
_io__raw_fci_block = KaitaiStream(BytesIO(self._raw_fci_block))
self.fci_block = RtcpPayload.PsfbAfbPacket(_io__raw_fci_block, self, self._root)
else:
self.fci_block = self._io.read_bytes_full()
@property
def fmt(self):
if hasattr(self, '_m_fmt'):
return self._m_fmt
self._m_fmt = KaitaiStream.resolve_enum(RtcpPayload.PsfbSubtype, self._parent.subtype)
return getattr(self, '_m_fmt', None)
class SourceChunk(KaitaiStruct):
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.ssrc = self._io.read_u4be()
self.sdes_tlv = []
i = 0
while not self._io.is_eof():
self.sdes_tlv.append(RtcpPayload.SdesTlv(self._io, self, self._root))
i += 1
class SdesPacket(KaitaiStruct):
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.source_chunk = []
for i in range(self.source_count):
self.source_chunk.append(RtcpPayload.SourceChunk(self._io, self, self._root))
@property
def source_count(self):
if hasattr(self, '_m_source_count'):
return self._m_source_count
self._m_source_count = self._parent.subtype
return getattr(self, '_m_source_count', None)
class RtpfbPacket(KaitaiStruct):
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.ssrc = self._io.read_u4be()
self.ssrc_media_source = self._io.read_u4be()
_on = self.fmt
if _on == RtcpPayload.RtpfbSubtype.transport_feedback:
self._raw_fci_block = self._io.read_bytes_full()
_io__raw_fci_block = KaitaiStream(BytesIO(self._raw_fci_block))
self.fci_block = RtcpPayload.RtpfbTransportFeedbackPacket(_io__raw_fci_block, self, self._root)
else:
self.fci_block = self._io.read_bytes_full()
@property
def fmt(self):
if hasattr(self, '_m_fmt'):
return self._m_fmt
self._m_fmt = KaitaiStream.resolve_enum(RtcpPayload.RtpfbSubtype, self._parent.subtype)
return getattr(self, '_m_fmt', None)
class PacketStatusChunk(KaitaiStruct):
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.t = self._io.read_bits_int_be(1) != 0
if int(self.t) == 0:
self.s2 = self._io.read_bits_int_be(2)
if int(self.t) == 1:
self.s1 = self._io.read_bits_int_be(1) != 0
if int(self.t) == 0:
self.rle = self._io.read_bits_int_be(13)
if int(self.t) == 1:
self.symbol_list = self._io.read_bits_int_be(14)
@property
def s(self):
if hasattr(self, '_m_s'):
return self._m_s
self._m_s = (self.s2 if int(self.t) == 0 else (1 if int(self.s1) == 0 else 0))
return getattr(self, '_m_s', None)
class PsfbAfbPacket(KaitaiStruct):
def __init__(self, _io, _parent=None, _root=None):
self._io = _io
self._parent = _parent
self._root = _root if _root else self
self._read()
def _read(self):
self.uid = self._io.read_u4be()
_on = self.uid
if _on == 1380273474:
self._raw_contents = self._io.read_bytes_full()
_io__raw_contents = KaitaiStream(BytesIO(self._raw_contents))
self.contents = RtcpPayload.PsfbAfbRembPacket(_io__raw_contents, self, self._root)
else:
self.contents = self._io.read_bytes_full()