IQ.Pilot Release Commit @ 3fe374f

iqpilot/system/webrtc/rtc/decoder.py

@@ -0,0 +1,52 @@
+# ruff: noqa: UP006, UP035
+
+import dataclasses
+import struct
+from typing import List
+
+
+@dataclasses.dataclass(frozen=True)
+class RtcpReceiverReport:
+  ssrc: int
+  fraction_lost: int
+  packets_lost: int
+  highest_seq_no: int
+  jitter: int
+  lsr: int
+  dlsr: int
+
+
+def _decode_receiver_reports(message: bytes) -> List[RtcpReceiverReport]:
+  reports: List[RtcpReceiverReport] = []
+  offset = 0
+
+  while offset + 4 <= len(message):
+    flags, packet_type, length_words = struct.unpack_from("!BBH", message, offset)
+    packet_end = offset + (length_words + 1) * 4
+    if flags >> 6 != 2 or packet_end > len(message):
+      break
+
+    report_count = flags & 0x1F
+    if packet_type == 200:  # Sender Report
+      report_offset = offset + 28
+    elif packet_type == 201:  # Receiver Report
+      report_offset = offset + 8
+    else:
+      offset = packet_end
+      continue
+
+    if report_offset + report_count * 24 > packet_end:
+      break
+
+    for i in range(report_count):
+      block_offset = report_offset + i * 24
+      ssrc, loss, highest_seq_no, jitter, lsr, dlsr = struct.unpack_from("!IIIIII", message, block_offset)
+      fraction_lost = loss >> 24
+      packets_lost = loss & 0xFFFFFF
+      if packets_lost & 0x800000:
+        packets_lost -= 1 << 24
+      reports.append(RtcpReceiverReport(ssrc, fraction_lost, packets_lost, highest_seq_no, jitter, lsr, dlsr))
+
+    offset = packet_end
+
+  return reports