install go2rtc on bob

installs_on_host/go2rtc/pkg/wav/wav.go

@@ -0,0 +1,103 @@
+package wav
+
+import (
+	"encoding/binary"
+	"io"
+
+	"github.com/AlexxIT/go2rtc/pkg/core"
+)
+
+func Header(codec *core.Codec) []byte {
+	var fmt, size, extra byte
+
+	switch codec.Name {
+	case core.CodecPCML:
+		fmt = 1
+		size = 2
+	case core.CodecPCMA:
+		fmt = 6
+		size = 1
+		extra = 2
+	case core.CodecPCMU:
+		fmt = 7
+		size = 1
+		extra = 2
+	default:
+		return nil
+	}
+
+	channels := byte(codec.Channels)
+	if channels == 0 {
+		channels = 1
+	}
+
+	b := make([]byte, 0, 46) // cap with extra
+	b = append(b, "RIFF\xFF\xFF\xFF\xFFWAVEfmt "...)
+
+	b = append(b, 0x10+extra, 0, 0, 0)
+	b = append(b, fmt, 0)
+	b = append(b, channels, 0)
+	b = binary.LittleEndian.AppendUint32(b, codec.ClockRate)
+	b = binary.LittleEndian.AppendUint32(b, uint32(size*channels)*codec.ClockRate)
+	b = append(b, size*channels, 0)
+	b = append(b, size*8, 0)
+	if extra > 0 {
+		b = append(b, 0, 0) // ExtraParamSize (if PCM, then doesn't exist)
+	}
+
+	b = append(b, "data\xFF\xFF\xFF\xFF"...)
+
+	return b
+}
+
+func ReadHeader(r io.Reader) (*core.Codec, error) {
+	// skip Master RIFF chunk
+	if _, err := io.ReadFull(r, make([]byte, 12)); err != nil {
+		return nil, err
+	}
+
+	var codec core.Codec
+
+	for {
+		chunkID, data, err := readChunk(r)
+		if err != nil {
+			return nil, err
+		}
+
+		if chunkID == "data" {
+			break
+		}
+
+		if chunkID == "fmt " {
+			// https://audiocoding.cc/articles/2008-05-22-wav-file-structure/wav_formats.txt
+			switch data[0] {
+			case 1:
+				codec.Name = core.CodecPCML
+			case 6:
+				codec.Name = core.CodecPCMA
+			case 7:
+				codec.Name = core.CodecPCMU
+			}
+
+			codec.Channels = data[2]
+			codec.ClockRate = binary.LittleEndian.Uint32(data[4:])
+		}
+	}
+
+	return &codec, nil
+}
+
+func readChunk(r io.Reader) (chunkID string, data []byte, err error) {
+	b := make([]byte, 8)
+	if _, err = io.ReadFull(r, b); err != nil {
+		return
+	}
+
+	if chunkID = string(b[:4]); chunkID != "data" {
+		size := binary.LittleEndian.Uint32(b[4:])
+		data = make([]byte, size)
+		_, err = io.ReadFull(r, data)
+	}
+
+	return
+}