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 +1,151 @@
+// Package pcm - support raw (verbatim) PCM 16 bit in the FLAC container:
+// - only 1 channel
+// - only 16 bit per sample
+// - only 8000, 16000, 24000, 48000 sample rate
+package pcm
+
+import (
+	"encoding/binary"
+	"unicode/utf8"
+
+	"github.com/AlexxIT/go2rtc/pkg/core"
+	"github.com/pion/rtp"
+	"github.com/sigurn/crc16"
+	"github.com/sigurn/crc8"
+)
+
+func FLACHeader(magic bool, sampleRate uint32) []byte {
+	b := make([]byte, 42)
+
+	if magic {
+		copy(b, "fLaC") // [0..3]
+	}
+
+	// https://xiph.org/flac/format.html#metadata_block_header
+	b[4] = 0x80 // [4] lastMetadata=1 (1 bit), blockType=0 - STREAMINFO (7 bit)
+	b[7] = 0x22 // [5..7] blockLength=34 (24 bit)
+
+	// Important for Apple QuickTime player:
+	// 1. Both values should be same
+	// 2. Maximum value = 32768
+	binary.BigEndian.PutUint16(b[8:], 32768)  // [8..9] info.BlockSizeMin=16 (16 bit)
+	binary.BigEndian.PutUint16(b[10:], 32768) // [10..11] info.BlockSizeMin=65535 (16 bit)
+
+	// [12..14] info.FrameSizeMin=0 (24 bit)
+	// [15..17] info.FrameSizeMax=0 (24 bit)
+
+	b[18] = byte(sampleRate >> 12)
+	b[19] = byte(sampleRate >> 4)
+	b[20] = byte(sampleRate << 4) // [18..20] info.SampleRate=8000 (20 bit), info.NChannels=1-1 (3 bit)
+
+	b[21] = 0xF0 // [21..25] info.BitsPerSample=16-1 (5 bit), info.NSamples (36 bit)
+
+	// [26..41] MD5sum (16 bytes)
+
+	return b
+}
+
+var table8 *crc8.Table
+var table16 *crc16.Table
+
+func FLACEncoder(codecName string, clockRate uint32, handler core.HandlerFunc) core.HandlerFunc {
+	var sr byte
+	switch clockRate {
+	case 8000:
+		sr = 0b0100
+	case 16000:
+		sr = 0b0101
+	case 22050:
+		sr = 0b0110
+	case 24000:
+		sr = 0b0111
+	case 32000:
+		sr = 0b1000
+	case 44100:
+		sr = 0b1001
+	case 48000:
+		sr = 0b1010
+	case 96000:
+		sr = 0b1011
+	default:
+		return nil
+	}
+
+	if table8 == nil {
+		table8 = crc8.MakeTable(crc8.CRC8)
+	}
+	if table16 == nil {
+		table16 = crc16.MakeTable(crc16.CRC16_BUYPASS)
+	}
+
+	var sampleNumber int32
+
+	return func(packet *rtp.Packet) {
+		samples := uint16(len(packet.Payload))
+
+		if codecName == core.CodecPCM || codecName == core.CodecPCML {
+			samples /= 2
+		}
+
+		// https://xiph.org/flac/format.html#frame_header
+		buf := make([]byte, samples*2+30)
+
+		// 1. Frame header
+		buf[0] = 0xFF
+		buf[1] = 0xF9      // [0..1] syncCode=0xFFF8 - reserved (15 bit), blockStrategy=1 - variable-blocksize (1 bit)
+		buf[2] = 0x70 | sr // blockSizeType=7 (4 bit), sampleRate=4 - 8000 (4 bit)
+		buf[3] = 0x08      // channels=1-1 (4 bit), sampleSize=4 - 16 (3 bit), reserved=0 (1 bit)
+
+		n := 4 + utf8.EncodeRune(buf[4:], sampleNumber) // 4 bytes max
+		sampleNumber += int32(samples)
+
+		// this is wrong but very simple frame block size value
+		binary.BigEndian.PutUint16(buf[n:], samples-1)
+		n += 2
+
+		buf[n] = crc8.Checksum(buf[:n], table8)
+		n += 1
+
+		// 2. Subframe header
+		buf[n] = 0x02 // padding=0 (1 bit), subframeType=1 - verbatim (6 bit), wastedFlag=0 (1 bit)
+		n += 1
+
+		// 3. Subframe
+		switch codecName {
+		case core.CodecPCMA:
+			for _, b := range packet.Payload {
+				s16 := PCMAtoPCM(b)
+				buf[n] = byte(s16 >> 8)
+				buf[n+1] = byte(s16)
+				n += 2
+			}
+		case core.CodecPCMU:
+			for _, b := range packet.Payload {
+				s16 := PCMUtoPCM(b)
+				buf[n] = byte(s16 >> 8)
+				buf[n+1] = byte(s16)
+				n += 2
+			}
+		case core.CodecPCM:
+			n += copy(buf[n:], packet.Payload)
+		case core.CodecPCML:
+			// reverse endian from little to big
+			size := len(packet.Payload)
+			for i := 0; i < size; i += 2 {
+				buf[n] = packet.Payload[i+1]
+				buf[n+1] = packet.Payload[i]
+				n += 2
+			}
+		}
+
+		// 4. Frame footer
+		crc := crc16.Checksum(buf[:n], table16)
+		binary.BigEndian.PutUint16(buf[n:], crc)
+		n += 2
+
+		clone := *packet
+		clone.Payload = buf[:n]
+
+		handler(&clone)
+	}
+}