b0e9ecdee7
- Add sACN/E1.31 protocol support for both input and output - from_proto = "sacn" to receive from sACN multicast - proto = "sacn" to output via sACN multicast - Fix remap engine to maintain persistent state per output universe - Multiple inputs targeting same output now merge correctly - Prevents flickering when multiple universes feed same output 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
103 lines
2.9 KiB
Go
103 lines
2.9 KiB
Go
package sacn
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import (
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"encoding/binary"
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"net"
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)
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const (
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Port = 5568
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// ACN packet identifiers
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ACNPacketIdentifier = 0x41534300 // "ASC\0" + more bytes
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// Vector values
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VectorRootE131Data = 0x00000004
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VectorE131DataPacket = 0x00000002
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VectorDMPSetProperty = 0x02
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)
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var (
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// ACN packet identifier (12 bytes)
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packetIdentifier = [12]byte{
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0x41, 0x53, 0x43, 0x2d, 0x45, 0x31, 0x2e, 0x31, 0x37, 0x00, 0x00, 0x00,
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}
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)
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// BuildDataPacket creates an E1.31 (sACN) data packet
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func BuildDataPacket(universe uint16, sequence uint8, sourceName string, cid [16]byte, data []byte) []byte {
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dataLen := len(data)
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if dataLen > 512 {
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dataLen = 512
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}
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// Total packet size: Root Layer (38) + Framing Layer (77) + DMP Layer (11 + data)
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// = 126 + dataLen
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pktLen := 126 + dataLen
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buf := make([]byte, pktLen)
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// Root Layer (38 bytes)
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// Preamble Size (2 bytes)
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binary.BigEndian.PutUint16(buf[0:2], 0x0010)
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// Post-amble Size (2 bytes)
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binary.BigEndian.PutUint16(buf[2:4], 0x0000)
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// ACN Packet Identifier (12 bytes)
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copy(buf[4:16], packetIdentifier[:])
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// Flags and Length (2 bytes) - high 4 bits are flags (0x7), low 12 bits are length
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rootLen := pktLen - 16 // Length from after ACN Packet Identifier
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binary.BigEndian.PutUint16(buf[16:18], 0x7000|uint16(rootLen))
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// Vector (4 bytes)
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binary.BigEndian.PutUint32(buf[18:22], VectorRootE131Data)
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// CID (16 bytes)
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copy(buf[22:38], cid[:])
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// Framing Layer (77 bytes, starting at offset 38)
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// Flags and Length (2 bytes)
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framingLen := pktLen - 38
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binary.BigEndian.PutUint16(buf[38:40], 0x7000|uint16(framingLen))
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// Vector (4 bytes)
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binary.BigEndian.PutUint32(buf[40:44], VectorE131DataPacket)
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// Source Name (64 bytes, null-terminated)
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copy(buf[44:108], sourceName)
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// Priority (1 byte)
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buf[108] = 100
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// Synchronization Address (2 bytes)
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binary.BigEndian.PutUint16(buf[109:111], 0)
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// Sequence Number (1 byte)
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buf[111] = sequence
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// Options (1 byte)
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buf[112] = 0
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// Universe (2 bytes)
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binary.BigEndian.PutUint16(buf[113:115], universe)
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// DMP Layer (11 + dataLen bytes, starting at offset 115)
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// Flags and Length (2 bytes)
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dmpLen := 11 + dataLen
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binary.BigEndian.PutUint16(buf[115:117], 0x7000|uint16(dmpLen))
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// Vector (1 byte)
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buf[117] = VectorDMPSetProperty
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// Address Type & Data Type (1 byte)
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buf[118] = 0xa1
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// First Property Address (2 bytes)
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binary.BigEndian.PutUint16(buf[119:121], 0)
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// Address Increment (2 bytes)
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binary.BigEndian.PutUint16(buf[121:123], 1)
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// Property Value Count (2 bytes) - includes START code
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binary.BigEndian.PutUint16(buf[123:125], uint16(dataLen+1))
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// START Code (1 byte)
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buf[125] = 0
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// Property Values (DMX data)
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copy(buf[126:], data[:dataLen])
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return buf
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}
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// MulticastAddr returns the multicast address for a given universe
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func MulticastAddr(universe uint16) *net.UDPAddr {
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// 239.255.{universe_high}.{universe_low}
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return &net.UDPAddr{
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IP: net.IPv4(239, 255, byte(universe>>8), byte(universe&0xff)),
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Port: Port,
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}
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}
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