Relay a Dante multicast stream to AES67. This assumes the AES67 device is synced to the same PTP master, as no PTP timestamping is done (timestamp from Dante is copied to AES67 RTP packet)

dante-aes67-relay.js

const dgram = require('dgram');
const client = dgram.createSocket({ type: 'udp4', reuseAddr: true });
const sdp = require('./sdp');

//config
const addr = '10.10.1.100';
const danteMulticast = '239.255.220.221';
const aes67Multicast = '239.69.1.122';
const samplerate = 48000;
const channels = 2;
const encoding = 'L24';
const name = 'Dante Multicast Relay';
const sessID = Math.round(Date.now() / 1000);
const sessVersion = sessID;
const ptpMaster = '08-00-00-ff-fe-00-00-1f:0';

//rtp specific vars
var seqNum = 0;

client.on('listening', function() {
	client.addMembership(danteMulticast, addr);
	client.setMulticastInterface(addr);
});

client.on('message', function(buffer, remote) {
	//read values from buffer
	var channelCount = buffer.readUInt8(0);
	var timestampSeconds = buffer.readUInt32BE(1);
	//bytes 6 and 7 seem to be always 0x00, maybe reserved bytes
	var timestampMedia = buffer.readUInt16BE(7);
	var pcmData = buffer.slice(9);

	//calculate media timestamp for rtp
	var timestampRTP = ((timestampSeconds * samplerate) + timestampMedia) & 0xffffffff;

	//create RTP header
	var rtpHeader = Buffer.alloc(12);
	rtpHeader.writeUInt16BE(0x8061, 0);
	rtpHeader.writeUInt16BE(seqNum, 2);
	rtpHeader.writeInt32BE(timestampRTP, 4);
	rtpHeader.writeUInt32BE(0xaf12af34, 8);

	//create and send RTP packet
	var rtpBuffer = Buffer.concat([rtpHeader, pcmData]);
	client.send(rtpBuffer, 5004, aes67Multicast);

	//increase seqnum
	seqNum = (seqNum + 1) % 65536;
});

client.bind(4321);
sdp.start(addr, aes67Multicast, samplerate, channels, encoding, name, sessID, sessVersion, ptpMaster);

sdp.js

var dgram = require('dgram');
var socket = dgram.createSocket({ type: 'udp4', reuseAddr: true });

var constructSDPMsg = function(addr, multicastAddr, samplerate, channels, encoding, name, sessID, sessVersion, ptpMaster){
	var sapHeader = Buffer.alloc(8);
	var sapContentType = Buffer.from('application/sdp\0');
	var ip = addr.split('.');

	//write version/options
	sapHeader.writeUInt8(0x20);

	//write hash
	sapHeader.writeUInt16LE(0xefef, 2);

	//write ip
	sapHeader.writeUInt8(parseInt(ip[0]), 4);
	sapHeader.writeUInt8(parseInt(ip[1]), 5);
	sapHeader.writeUInt8(parseInt(ip[2]), 6);
	sapHeader.writeUInt8(parseInt(ip[3]), 7);

	var sdpConfig = [
		'v=0',
		'o=- '+sessID+' '+sessVersion+' IN IP4 '+addr,
		's='+name,
		'c=IN IP4 '+multicastAddr+'/32',
		't=0 0',
		'a=clock-domain:PTPv2 0',
		'm=audio 5004 RTP/AVP 96',
		'a=rtpmap:96 '+encoding+'/'+samplerate+'/'+channels,
		'a=sync-time:0',
		'a=framecount:48',
		'a=ptime:1',
		'a=mediaclk:direct=0',
		'a=ts-refclk:ptp=IEEE1588-2008:'+ptpMaster,
		'a=recvonly',
		''
	];

	var sdpBody = Buffer.from(sdpConfig.join('\r\n'));

	return Buffer.concat([sapHeader, sapContentType, sdpBody]);
}

exports.start = function(addr, multicastAddr, samplerate, channels, encoding, name, sessID, sessVersion, ptpMaster){
	sdpMSG = constructSDPMsg(addr, multicastAddr, samplerate, channels, encoding, name, sessID, sessVersion, ptpMaster);

	socket.bind(9875, function(){
		socket.setMulticastInterface(addr);
		socket.send(sdpMSG, 9875, '239.255.255.255', function(err){});
	});
	
	setInterval(function(){
		socket.send(sdpMSG, 9875, '239.255.255.255', function(err){});
	}, 30*1000);
}

This is amazing! It works very smooth with my i7-7567U. I have an AES67 box that acts as a PTPv2 master, Audinate AVIO dongle on the network, and this same computer runs Dante Virtual Soundcard.. I routed this computers Dante to the AVIO and then used that stream to be replicated with your script. Only issue was that the payload type was not correct on the SDP (RTP stream had payload type 97, but SDP told it was 96), but that was an easy fix of course.

This works excellently with Dante VSC (by far the most reliable windows driver I've found). As mmoduu said, you'll have to change the payload type to 97 and at least for me, when I'm trying to receive an 8 ch stream with the Merging ALSA driver, I have to map it to 8 channels.

Using an AVIO as the boundary clock between PTPv1 and v2. You can probably do this yourself or there's a project on here that describes how to intercept and then 'spawn' Dante VSC's PTP process to connect to a v2 source. It's for Mac but the premise should in theory work for Windows too if you re-write the code.