feat: added record qso dvk

internal/audio/wav.go

@@ -0,0 +1,86 @@
+//go:build windows
+
+package audio
+
+import (
+	"encoding/binary"
+	"fmt"
+	"os"
+)
+
+// The DVK/recorder pipeline uses a single fixed PCM format end-to-end: 16 kHz
+// mono 16-bit. That's plenty for SSB voice (3 kHz audio bandwidth), keeps files
+// tiny (~32 KB/s), and — fed through WASAPI's AUTOCONVERTPCM — plays/records on
+// any device regardless of its native mix format.
+const (
+	sampleRate    = 16000
+	channels      = 1
+	bitsPerSample = 16
+	blockAlign    = channels * bitsPerSample / 8 // bytes per frame (=2)
+	bytesPerSec   = sampleRate * blockAlign      // =32000
+)
+
+// writeWAV writes 16-bit PCM as a canonical RIFF/WAVE file.
+func writeWAV(path string, pcm []byte) error {
+	f, err := os.Create(path)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	dataLen := len(pcm)
+	put := func(v any) { _ = binary.Write(f, binary.LittleEndian, v) }
+	f.WriteString("RIFF")
+	put(uint32(36 + dataLen))
+	f.WriteString("WAVE")
+	f.WriteString("fmt ")
+	put(uint32(16))               // PCM fmt chunk size
+	put(uint16(1))                // WAVE_FORMAT_PCM
+	put(uint16(channels))         //
+	put(uint32(sampleRate))       //
+	put(uint32(bytesPerSec))      // byte rate
+	put(uint16(blockAlign))       //
+	put(uint16(bitsPerSample))    //
+	f.WriteString("data")
+	put(uint32(dataLen))
+	_, err = f.Write(pcm)
+	return err
+}
+
+// readWAV reads a PCM WAV and returns the raw sample bytes plus its format.
+// Handles arbitrary chunk ordering (walks the RIFF chunk list).
+func readWAV(path string) (pcm []byte, rate, ch, bits int, err error) {
+	b, err := os.ReadFile(path)
+	if err != nil {
+		return nil, 0, 0, 0, err
+	}
+	if len(b) < 12 || string(b[0:4]) != "RIFF" || string(b[8:12]) != "WAVE" {
+		return nil, 0, 0, 0, fmt.Errorf("not a WAVE file")
+	}
+	i := 12
+	for i+8 <= len(b) {
+		id := string(b[i : i+4])
+		size := int(binary.LittleEndian.Uint32(b[i+4 : i+8]))
+		body := i + 8
+		if body+size > len(b) {
+			size = len(b) - body
+		}
+		switch id {
+		case "fmt ":
+			if size >= 16 {
+				ch = int(binary.LittleEndian.Uint16(b[body+2 : body+4]))
+				rate = int(binary.LittleEndian.Uint32(b[body+4 : body+8]))
+				bits = int(binary.LittleEndian.Uint16(b[body+14 : body+16]))
+			}
+		case "data":
+			pcm = b[body : body+size]
+		}
+		i = body + size
+		if size%2 == 1 {
+			i++ // chunks are word-aligned
+		}
+	}
+	if pcm == nil || rate == 0 {
+		return nil, 0, 0, 0, fmt.Errorf("WAV missing fmt/data")
+	}
+	return pcm, rate, ch, bits, nil
+}