Initial commit: LiveStream Platform

Backend: FastAPI + SQLAlchemy + SQLite
Frontend: React + Vite + Ant Design (serif Anthropic theme)
Media server: MediaMTX with edge node support
Load balancing: round-robin / weighted / least-conn
Multicast detection with automatic fallback
Transcoding support via FFmpeg (configurable quality)
hls.js player with line & quality switching
Admin panel with password auth
Windows compatible scripts

backend/services/multicast_detector.py

@@ -0,0 +1,64 @@
+import socket
+import struct
+import asyncio
+from config import settings
+
+
+def check_multicast_reachable(mcast_addr: str = "239.0.0.1", port: int = 9999, timeout: float = 2.0) -> bool:
+    try:
+        sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
+        sock.settimeout(timeout)
+        ttl = struct.pack("b", 1)
+        sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, ttl)
+
+        mreq = struct.pack("4sL", socket.inet_aton(mcast_addr), socket.INADDR_ANY)
+        sock.setsockopt(socket.IPPROTO_IP, socket.IP_ADD_MEMBERSHIP, mreq)
+
+        sock.sendto(b"ping", (mcast_addr, port))
+        try:
+            data, addr = sock.recvfrom(1024)
+            sock.close()
+            return True
+        except socket.timeout:
+            sock.close()
+            return True
+    except Exception:
+        return False
+
+
+class MulticastDetector:
+    def __init__(self):
+        self._multicast_available: bool | None = None
+
+    def is_available(self) -> bool:
+        if self._multicast_available is not None:
+            return self._multicast_available
+
+        if not settings.multicast_enabled:
+            self._multicast_available = False
+            return False
+
+        self._multicast_available = check_multicast_reachable()
+        return self._multicast_available
+
+    def get_stream_url(self, stream_key: str, node: dict, quality: dict | None = None):
+        use_multicast = self.is_available()
+        host = node["host"]
+
+        if use_multicast:
+            hash_val = abs(hash(stream_key)) % 255
+            mcast_addr = f"{settings.multicast_address_base.rsplit('.', 1)[0]}.{hash_val + 1}"
+            mcast_port = settings.multicast_port_base + (abs(hash(stream_key)) % 1000)
+            return {
+                "type": "multicast",
+                "url": f"udp://@{mcast_addr}:{mcast_port}",
+                "unicast_fallback": f"http://{host}:{node['hls_port']}/{stream_key}/index.m3u8",
+            }
+
+        return {
+            "type": "hls",
+            "url": f"http://{host}:{node['hls_port']}/{stream_key}/index.m3u8",
+        }
+
+
+multicast_detector = MulticastDetector()