github-actions[bot]
5c97379765
date: 2026-08-01T16:05:18 master commit: 3a05c03079d796f533f342489b3f681cfd21f98d
51 lines
1.4 KiB
Python
51 lines
1.4 KiB
Python
import dataclasses
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import struct
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from typing import List
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@dataclasses.dataclass(frozen=True)
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class RtcpReceiverReport:
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ssrc: int
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fraction_lost: int
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packets_lost: int
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highest_seq_no: int
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jitter: int
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lsr: int
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dlsr: int
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def _decode_receiver_reports(message: bytes) -> List[RtcpReceiverReport]:
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reports: List[RtcpReceiverReport] = []
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offset = 0
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while offset + 4 <= len(message):
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flags, packet_type, length_words = struct.unpack_from("!BBH", message, offset)
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packet_end = offset + (length_words + 1) * 4
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if flags >> 6 != 2 or packet_end > len(message):
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break
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report_count = flags & 0x1F
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if packet_type == 200: # Sender Report
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report_offset = offset + 28
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elif packet_type == 201: # Receiver Report
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report_offset = offset + 8
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else:
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offset = packet_end
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continue
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if report_offset + report_count * 24 > packet_end:
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break
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for i in range(report_count):
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block_offset = report_offset + i * 24
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ssrc, loss, highest_seq_no, jitter, lsr, dlsr = struct.unpack_from("!IIIIII", message, block_offset)
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fraction_lost = loss >> 24
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packets_lost = loss & 0xFFFFFF
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if packets_lost & 0x800000:
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packets_lost -= 1 << 24
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reports.append(RtcpReceiverReport(ssrc, fraction_lost, packets_lost, highest_seq_no, jitter, lsr, dlsr))
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offset = packet_end
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return reports
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