Aiortc library

Abstract	aiortc library
Authors	Walter Fan
Status	WIP
Updated	2024-08-21

Overview 

Signal 

信令通道的主要功能是交换 SDP 和 Candidate

def create_signaling(args):
    """
    Create a signaling method based on command-line arguments.
    """
    if args.signaling == "tcp-socket":
        return TcpSocketSignaling(args.signaling_host, args.signaling_port)
    elif args.signaling == "unix-socket":
        return UnixSocketSignaling(args.signaling_path)
    else:
        return CopyAndPasteSignaling()

datachannel 

offer

v=0
o=- 3860702636 3860702636 IN IP4 0.0.0.0
s=-
t=0 0
a=group:BUNDLE 0
a=msid-semantic:WMS *
m=application 55755 DTLS/SCTP 5000
c=IN IP4 10.140.202.80
a=mid:0
a=sctpmap:5000 webrtc-datachannel 65535
a=max-message-size:65536
a=candidate:bcdcd0d77830c06b899667d1432cdd1b 1 udp 2130706431 10.140.202.80 55755 typ host
a=candidate:0a02eb4cf64a7c80c396dc8996ae84dc 1 udp 2130706431 2001:420:5899:1252:2837:7baa:38d1:6375 58942 typ host
a=end-of-candidates
a=ice-ufrag:j8I1
a=ice-pwd:AbyIZUKw1AeWitiEDfVZ7M
a=fingerprint:sha-256 AA:9E:FF:30:84:B0:56:59:35:2F:20:C6:37:3D:29:92:4E:8E:76:C7:4F:C2:78:CA:38:EC:69:B5:71:AE:9A:A6
a=setup:actpass

answer

v=0
o=- 3860704408 3860704408 IN IP4 0.0.0.0
s=-
t=0 0
a=group:BUNDLE 0
a=msid-semantic:WMS *
m=application 63629 DTLS/SCTP 5000
c=IN IP4 10.140.202.80
a=mid:0
a=sctpmap:5000 webrtc-datachannel 65535
a=max-message-size:65536
a=candidate:bcdcd0d77830c06b899667d1432cdd1b 1 udp 2130706431 10.140.202.80 63629 typ host
a=candidate:0a02eb4cf64a7c80c396dc8996ae84dc 1 udp 2130706431 2001:420:5899:1252:2837:7baa:38d1:6375 60972 typ host
a=end-of-candidates
a=ice-ufrag:EbS2
a=ice-pwd:ngG0BJGSJgQpbglkHxo8tx
a=fingerprint:sha-256 F3:D3:48:D2:BC:97:83:A9:88:34:30:B9:9A:2F:1A:C4:F5:DF:B4:C1:8D:89:CE:63:E9:37:1F:B7:57:54:48:8E
a=setup:active

RTP packet 处理 

https://github.com/aiortc/aiortc/blob/main/src/aiortc/rtp.py

对于 RTP 的打包和解包应用了 Python Structure module`_

‘>BBHL{payload}s’