install go2rtc on bob

2026-04-04 19:36:14 +02:00
parent f0b56e63d1
commit ccf88187b8
537 changed files with 69213 additions and 0 deletions
@@ -0,0 +1,195 @@
+package h264
+
+import "encoding/binary"
+
+// Payloader payloads H264 packets
+type Payloader struct {
+	IsAVC     bool
+	stapANalu []byte
+}
+
+const (
+	stapaNALUType  = 24
+	fuaNALUType    = 28
+	fubNALUType    = 29
+	spsNALUType    = 7
+	ppsNALUType    = 8
+	audNALUType    = 9
+	fillerNALUType = 12
+
+	fuaHeaderSize = 2
+	//stapaHeaderSize     = 1
+	//stapaNALULengthSize = 2
+
+	naluTypeBitmask   = 0x1F
+	naluRefIdcBitmask = 0x60
+	//fuStartBitmask    = 0x80
+	//fuEndBitmask      = 0x40
+
+	outputStapAHeader = 0x78
+)
+
+//func annexbNALUStartCode() []byte { return []byte{0x00, 0x00, 0x00, 0x01} }
+
+func EmitNalus(nals []byte, isAVC bool, emit func([]byte)) {
+	if !isAVC {
+		nextInd := func(nalu []byte, start int) (indStart int, indLen int) {
+			zeroCount := 0
+
+			for i, b := range nalu[start:] {
+				if b == 0 {
+					zeroCount++
+					continue
+				} else if b == 1 {
+					if zeroCount >= 2 {
+						return start + i - zeroCount, zeroCount + 1
+					}
+				}
+				zeroCount = 0
+			}
+			return -1, -1
+		}
+
+		nextIndStart, nextIndLen := nextInd(nals, 0)
+		if nextIndStart == -1 {
+			emit(nals)
+		} else {
+			for nextIndStart != -1 {
+				prevStart := nextIndStart + nextIndLen
+				nextIndStart, nextIndLen = nextInd(nals, prevStart)
+				if nextIndStart != -1 {
+					emit(nals[prevStart:nextIndStart])
+				} else {
+					// Emit until end of stream, no end indicator found
+					emit(nals[prevStart:])
+				}
+			}
+		}
+	} else {
+		for {
+			n := uint32(len(nals))
+			if n < 4 {
+				break
+			}
+			end := 4 + binary.BigEndian.Uint32(nals)
+			if n < end {
+				break
+			}
+			emit(nals[4:end])
+			nals = nals[end:]
+		}
+	}
+}
+
+// Payload fragments a H264 packet across one or more byte arrays
+func (p *Payloader) Payload(mtu uint16, payload []byte) [][]byte {
+	var payloads [][]byte
+	if len(payload) == 0 {
+		return payloads
+	}
+
+	EmitNalus(payload, p.IsAVC, func(nalu []byte) {
+		if len(nalu) == 0 {
+			return
+		}
+
+		naluType := nalu[0] & naluTypeBitmask
+		naluRefIdc := nalu[0] & naluRefIdcBitmask
+
+		switch naluType {
+		case audNALUType, fillerNALUType:
+			return
+		case spsNALUType, ppsNALUType:
+			if p.stapANalu == nil {
+				p.stapANalu = []byte{outputStapAHeader}
+			}
+			p.stapANalu = append(p.stapANalu, byte(len(nalu)>>8), byte(len(nalu)))
+			p.stapANalu = append(p.stapANalu, nalu...)
+			return
+		}
+
+		if p.stapANalu != nil {
+			// Pack current NALU with SPS and PPS as STAP-A
+			// Supports multiple PPS in a row
+			if len(p.stapANalu) <= int(mtu) {
+				payloads = append(payloads, p.stapANalu)
+			}
+			p.stapANalu = nil
+		}
+
+		// Single NALU
+		if len(nalu) <= int(mtu) {
+			out := make([]byte, len(nalu))
+			copy(out, nalu)
+			payloads = append(payloads, out)
+			return
+		}
+
+		// FU-A
+		maxFragmentSize := int(mtu) - fuaHeaderSize
+
+		// The FU payload consists of fragments of the payload of the fragmented
+		// NAL unit so that if the fragmentation unit payloads of consecutive
+		// FUs are sequentially concatenated, the payload of the fragmented NAL
+		// unit can be reconstructed.  The NAL unit type octet of the fragmented
+		// NAL unit is not included as such in the fragmentation unit payload,
+		// 	but rather the information of the NAL unit type octet of the
+		// fragmented NAL unit is conveyed in the F and NRI fields of the FU
+		// indicator octet of the fragmentation unit and in the type field of
+		// the FU header.  An FU payload MAY have any number of octets and MAY
+		// be empty.
+
+		naluData := nalu
+		// According to the RFC, the first octet is skipped due to redundant information
+		naluDataIndex := 1
+		naluDataLength := len(nalu) - naluDataIndex
+		naluDataRemaining := naluDataLength
+
+		if min(maxFragmentSize, naluDataRemaining) <= 0 {
+			return
+		}
+
+		for naluDataRemaining > 0 {
+			currentFragmentSize := min(maxFragmentSize, naluDataRemaining)
+			out := make([]byte, fuaHeaderSize+currentFragmentSize)
+
+			// +---------------+
+			// |0|1|2|3|4|5|6|7|
+			// +-+-+-+-+-+-+-+-+
+			// |F|NRI|  Type   |
+			// +---------------+
+			out[0] = fuaNALUType
+			out[0] |= naluRefIdc
+
+			// +---------------+
+			// |0|1|2|3|4|5|6|7|
+			// +-+-+-+-+-+-+-+-+
+			// |S|E|R|  Type   |
+			// +---------------+
+
+			out[1] = naluType
+			if naluDataRemaining == naluDataLength {
+				// Set start bit
+				out[1] |= 1 << 7
+			} else if naluDataRemaining-currentFragmentSize == 0 {
+				// Set end bit
+				out[1] |= 1 << 6
+			}
+
+			copy(out[fuaHeaderSize:], naluData[naluDataIndex:naluDataIndex+currentFragmentSize])
+			payloads = append(payloads, out)
+
+			naluDataRemaining -= currentFragmentSize
+			naluDataIndex += currentFragmentSize
+		}
+	})
+
+	return payloads
+}
+
+func min(a, b int) int {
+	if a < b {
+		return a
+	}
+	return b
+}