1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
|
package extra
import (
"bytes"
"encoding/binary"
"errors"
"fmt"
"io"
"log/slog"
"mime/multipart"
"net/http"
"regexp"
"strings"
"github.com/gordonklaus/portaudio"
)
var specialRE = regexp.MustCompile(`\[.*?\]`)
type STT interface {
StartRecording() error
StopRecording() (string, error)
IsRecording() bool
}
type StreamCloser interface {
Close() error
}
type WhisperSTT struct {
logger *slog.Logger
ServerURL string
SampleRate int
AudioBuffer *bytes.Buffer
streamer StreamCloser
recording bool
}
func NewWhisperSTT(logger *slog.Logger, serverURL string, sampleRate int) *WhisperSTT {
return &WhisperSTT{
logger: logger,
ServerURL: serverURL,
SampleRate: sampleRate,
AudioBuffer: new(bytes.Buffer),
}
}
func (stt *WhisperSTT) StartRecording() error {
if err := stt.microphoneStream(stt.SampleRate); err != nil {
return fmt.Errorf("failed to init microphone: %w", err)
}
stt.recording = true
return nil
}
func (stt *WhisperSTT) StopRecording() (string, error) {
stt.recording = false
// wait loop to finish?
if stt.AudioBuffer == nil {
err := errors.New("unexpected nil AudioBuffer")
stt.logger.Error(err.Error())
return "", err
}
// Create WAV header first
body := &bytes.Buffer{}
writer := multipart.NewWriter(body)
// Add audio file part
part, err := writer.CreateFormFile("file", "recording.wav")
if err != nil {
stt.logger.Error("fn: StopRecording", "error", err)
return "", err
}
// Stream directly to multipart writer: header + raw data
dataSize := stt.AudioBuffer.Len()
stt.writeWavHeader(part, dataSize)
if _, err := io.Copy(part, stt.AudioBuffer); err != nil {
stt.logger.Error("fn: StopRecording", "error", err)
return "", err
}
// Reset buffer for next recording
stt.AudioBuffer.Reset()
// Add response format field
err = writer.WriteField("response_format", "text")
if err != nil {
stt.logger.Error("fn: StopRecording", "error", err)
return "", err
}
if writer.Close() != nil {
stt.logger.Error("fn: StopRecording", "error", err)
return "", err
}
// Send request
resp, err := http.Post("http://localhost:8081/inference", writer.FormDataContentType(), body)
if err != nil {
stt.logger.Error("fn: StopRecording", "error", err)
return "", err
}
defer resp.Body.Close()
// Read and print response
responseTextBytes, err := io.ReadAll(resp.Body)
if err != nil {
stt.logger.Error("fn: StopRecording", "error", err)
return "", err
}
resptext := strings.TrimRight(string(responseTextBytes), "\n")
// in case there are special tokens like [_BEG_]
return specialRE.ReplaceAllString(resptext, ""), nil
}
func (stt *WhisperSTT) writeWavHeader(w io.Writer, dataSize int) {
header := make([]byte, 44)
copy(header[0:4], "RIFF")
binary.LittleEndian.PutUint32(header[4:8], uint32(36+dataSize))
copy(header[8:12], "WAVE")
copy(header[12:16], "fmt ")
binary.LittleEndian.PutUint32(header[16:20], 16)
binary.LittleEndian.PutUint16(header[20:22], 1)
binary.LittleEndian.PutUint16(header[22:24], 1)
binary.LittleEndian.PutUint32(header[24:28], uint32(stt.SampleRate))
binary.LittleEndian.PutUint32(header[28:32], uint32(stt.SampleRate)*1*(16/8))
binary.LittleEndian.PutUint16(header[32:34], 1*(16/8))
binary.LittleEndian.PutUint16(header[34:36], 16)
copy(header[36:40], "data")
binary.LittleEndian.PutUint32(header[40:44], uint32(dataSize))
w.Write(header)
}
func (stt *WhisperSTT) IsRecording() bool {
return stt.recording
}
func (stt *WhisperSTT) microphoneStream(sampleRate int) error {
if err := portaudio.Initialize(); err != nil {
return fmt.Errorf("portaudio init failed: %w", err)
}
in := make([]int16, 64)
stream, err := portaudio.OpenDefaultStream(1, 0, float64(sampleRate), len(in), in)
if err != nil {
portaudio.Terminate()
return fmt.Errorf("failed to open microphone: %w", err)
}
go func(stream *portaudio.Stream) {
if err := stream.Start(); err != nil {
stt.logger.Error("microphoneStream", "error", err)
return
}
for {
if !stt.IsRecording() {
return
}
if err := stream.Read(); err != nil {
stt.logger.Error("reading stream", "error", err)
return
}
if err := binary.Write(stt.AudioBuffer, binary.LittleEndian, in); err != nil {
stt.logger.Error("writing to buffer", "error", err)
return
}
}
}(stream)
return nil
}
|
