File size: 7,413 Bytes
6457591
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
use crate::{silero, utils};

const DEBUG_SPEECH_PROB: bool = true;
#[derive(Debug)]
pub struct VadIter {
    silero: silero::Silero,
    params: Params,
    state: State,
}

impl VadIter {
    pub fn new(silero: silero::Silero, params: utils::VadParams) -> Self {
        Self {
            silero,
            params: Params::from(params),
            state: State::new(),
        }
    }

    pub fn process(&mut self, samples: &[i16]) -> Result<(), ort::Error> {
        self.reset_states();
        for audio_frame in samples.chunks_exact(self.params.frame_size_samples) {
            let speech_prob: f32 = self.silero.calc_level(audio_frame)?;
            self.state.update(&self.params, speech_prob);
        }
        self.state.check_for_last_speech(samples.len());
        Ok(())
    }

    pub fn speeches(&self) -> &[utils::TimeStamp] {
        &self.state.speeches
    }
}

impl VadIter {
    fn reset_states(&mut self) {
        self.silero.reset();
        self.state = State::new()
    }
}

#[allow(unused)]
#[derive(Debug)]
struct Params {
    frame_size: usize,
    threshold: f32,
    min_silence_duration_ms: usize,
    speech_pad_ms: usize,
    min_speech_duration_ms: usize,
    max_speech_duration_s: f32,
    sample_rate: usize,
    sr_per_ms: usize,
    frame_size_samples: usize,
    min_speech_samples: usize,
    speech_pad_samples: usize,
    max_speech_samples: f32,
    min_silence_samples: usize,
    min_silence_samples_at_max_speech: usize,
}

impl From<utils::VadParams> for Params {
    fn from(value: utils::VadParams) -> Self {
        let frame_size = value.frame_size;
        let threshold = value.threshold;
        let min_silence_duration_ms = value.min_silence_duration_ms;
        let speech_pad_ms = value.speech_pad_ms;
        let min_speech_duration_ms = value.min_speech_duration_ms;
        let max_speech_duration_s = value.max_speech_duration_s;
        let sample_rate = value.sample_rate;
        let sr_per_ms = sample_rate / 1000;
        let frame_size_samples = frame_size * sr_per_ms;
        let min_speech_samples = sr_per_ms * min_speech_duration_ms;
        let speech_pad_samples = sr_per_ms * speech_pad_ms;
        let max_speech_samples = sample_rate as f32 * max_speech_duration_s
            - frame_size_samples as f32
            - 2.0 * speech_pad_samples as f32;
        let min_silence_samples = sr_per_ms * min_silence_duration_ms;
        let min_silence_samples_at_max_speech = sr_per_ms * 98;
        Self {
            frame_size,
            threshold,
            min_silence_duration_ms,
            speech_pad_ms,
            min_speech_duration_ms,
            max_speech_duration_s,
            sample_rate,
            sr_per_ms,
            frame_size_samples,
            min_speech_samples,
            speech_pad_samples,
            max_speech_samples,
            min_silence_samples,
            min_silence_samples_at_max_speech,
        }
    }
}

#[derive(Debug, Default)]
struct State {
    current_sample: usize,
    temp_end: usize,
    next_start: usize,
    prev_end: usize,
    triggered: bool,
    current_speech: utils::TimeStamp,
    speeches: Vec<utils::TimeStamp>,
}

impl State {
    fn new() -> Self {
        Default::default()
    }

    fn update(&mut self, params: &Params, speech_prob: f32) {
        self.current_sample += params.frame_size_samples;
        if speech_prob > params.threshold {
            if self.temp_end != 0 {
                self.temp_end = 0;
                if self.next_start < self.prev_end {
                    self.next_start = self
                        .current_sample
                        .saturating_sub(params.frame_size_samples)
                }
            }
            if !self.triggered {
                self.debug(speech_prob, params, "start");
                self.triggered = true;
                self.current_speech.start =
                    self.current_sample as i64 - params.frame_size_samples as i64;
            }
            return;
        }
        if self.triggered
            && (self.current_sample as i64 - self.current_speech.start) as f32
                > params.max_speech_samples
        {
            if self.prev_end > 0 {
                self.current_speech.end = self.prev_end as _;
                self.take_speech();
                if self.next_start < self.prev_end {
                    self.triggered = false
                } else {
                    self.current_speech.start = self.next_start as _;
                }
                self.prev_end = 0;
                self.next_start = 0;
                self.temp_end = 0;
            } else {
                self.current_speech.end = self.current_sample as _;
                self.take_speech();
                self.prev_end = 0;
                self.next_start = 0;
                self.temp_end = 0;
                self.triggered = false;
            }
            return;
        }
        if speech_prob >= (params.threshold - 0.15) && (speech_prob < params.threshold) {
            if self.triggered {
                self.debug(speech_prob, params, "speaking")
            } else {
                self.debug(speech_prob, params, "silence")
            }
        }
        if self.triggered && speech_prob < (params.threshold - 0.15) {
            self.debug(speech_prob, params, "end");
            if self.temp_end == 0 {
                self.temp_end = self.current_sample;
            }
            if self.current_sample.saturating_sub(self.temp_end)
                > params.min_silence_samples_at_max_speech
            {
                self.prev_end = self.temp_end;
            }
            if self.current_sample.saturating_sub(self.temp_end) >= params.min_silence_samples {
                self.current_speech.end = self.temp_end as _;
                if self.current_speech.end - self.current_speech.start
                    > params.min_speech_samples as _
                {
                    self.take_speech();
                    self.prev_end = 0;
                    self.next_start = 0;
                    self.temp_end = 0;
                    self.triggered = false;
                }
            }
        }
    }

    fn take_speech(&mut self) {
        self.speeches.push(std::mem::take(&mut self.current_speech)); // current speech becomes TimeStamp::default() due to take()
    }

    fn check_for_last_speech(&mut self, last_sample: usize) {
        if self.current_speech.start > 0 {
            self.current_speech.end = last_sample as _;
            self.take_speech();
            self.prev_end = 0;
            self.next_start = 0;
            self.temp_end = 0;
            self.triggered = false;
        }
    }

    fn debug(&self, speech_prob: f32, params: &Params, title: &str) {
        if DEBUG_SPEECH_PROB {
            let speech = self.current_sample as f32
                - params.frame_size_samples as f32
                - if title == "end" {
                    params.speech_pad_samples
                } else {
                    0
                } as f32; // minus window_size_samples to get precise start time point.
            println!(
                "[{:10}: {:.3} s ({:.3}) {:8}]",
                title,
                speech / params.sample_rate as f32,
                speech_prob,
                self.current_sample - params.frame_size_samples,
            );
        }
    }
}