FunASR/funasr/models/e2e_vad.py

from enum import Enum
from typing import List, Tuple, Dict, Any

import torch
from torch import nn
import math
from funasr.models.encoder.fsmn_encoder import FSMN


class VadStateMachine(Enum):
    kVadInStateStartPointNotDetected = 1
    kVadInStateInSpeechSegment = 2
    kVadInStateEndPointDetected = 3


class FrameState(Enum):
    kFrameStateInvalid = -1
    kFrameStateSpeech = 1
    kFrameStateSil = 0


# final voice/unvoice state per frame
class AudioChangeState(Enum):
    kChangeStateSpeech2Speech = 0
    kChangeStateSpeech2Sil = 1
    kChangeStateSil2Sil = 2
    kChangeStateSil2Speech = 3
    kChangeStateNoBegin = 4
    kChangeStateInvalid = 5


class VadDetectMode(Enum):
    kVadSingleUtteranceDetectMode = 0
    kVadMutipleUtteranceDetectMode = 1


class VADXOptions:
    def __init__(
            self,
            sample_rate: int = 16000,
            detect_mode: int = VadDetectMode.kVadMutipleUtteranceDetectMode.value,
            snr_mode: int = 0,
            max_end_silence_time: int = 800,
            max_start_silence_time: int = 3000,
            do_start_point_detection: bool = True,
            do_end_point_detection: bool = True,
            window_size_ms: int = 200,
            sil_to_speech_time_thres: int = 150,
            speech_to_sil_time_thres: int = 150,
            speech_2_noise_ratio: float = 1.0,
            do_extend: int = 1,
            lookback_time_start_point: int = 200,
            lookahead_time_end_point: int = 100,
            max_single_segment_time: int = 60000,
            nn_eval_block_size: int = 8,
            dcd_block_size: int = 4,
            snr_thres: int = -100.0,
            noise_frame_num_used_for_snr: int = 100,
            decibel_thres: int = -100.0,
            speech_noise_thres: float = 0.6,
            fe_prior_thres: float = 1e-4,
            silence_pdf_num: int = 1,
            sil_pdf_ids: List[int] = [0],
            speech_noise_thresh_low: float = -0.1,
            speech_noise_thresh_high: float = 0.3,
            output_frame_probs: bool = False,
            frame_in_ms: int = 10,
            frame_length_ms: int = 25,
    ):
        self.sample_rate = sample_rate
        self.detect_mode = detect_mode
        self.snr_mode = snr_mode
        self.max_end_silence_time = max_end_silence_time
        self.max_start_silence_time = max_start_silence_time
        self.do_start_point_detection = do_start_point_detection
        self.do_end_point_detection = do_end_point_detection
        self.window_size_ms = window_size_ms
        self.sil_to_speech_time_thres = sil_to_speech_time_thres
        self.speech_to_sil_time_thres = speech_to_sil_time_thres
        self.speech_2_noise_ratio = speech_2_noise_ratio
        self.do_extend = do_extend
        self.lookback_time_start_point = lookback_time_start_point
        self.lookahead_time_end_point = lookahead_time_end_point
        self.max_single_segment_time = max_single_segment_time
        self.nn_eval_block_size = nn_eval_block_size
        self.dcd_block_size = dcd_block_size
        self.snr_thres = snr_thres
        self.noise_frame_num_used_for_snr = noise_frame_num_used_for_snr
        self.decibel_thres = decibel_thres
        self.speech_noise_thres = speech_noise_thres
        self.fe_prior_thres = fe_prior_thres
        self.silence_pdf_num = silence_pdf_num
        self.sil_pdf_ids = sil_pdf_ids
        self.speech_noise_thresh_low = speech_noise_thresh_low
        self.speech_noise_thresh_high = speech_noise_thresh_high
        self.output_frame_probs = output_frame_probs
        self.frame_in_ms = frame_in_ms
        self.frame_length_ms = frame_length_ms


class E2EVadSpeechBufWithDoa(object):
    def __init__(self):
        self.start_ms = 0
        self.end_ms = 0
        self.buffer = []
        self.contain_seg_start_point = False
        self.contain_seg_end_point = False
        self.doa = 0

    def Reset(self):
        self.start_ms = 0
        self.end_ms = 0
        self.buffer = []
        self.contain_seg_start_point = False
        self.contain_seg_end_point = False
        self.doa = 0


class E2EVadFrameProb(object):
    def __init__(self):
        self.noise_prob = 0.0
        self.speech_prob = 0.0
        self.score = 0.0
        self.frame_id = 0
        self.frm_state = 0


class WindowDetector(object):
    def __init__(self, window_size_ms: int, sil_to_speech_time: int,
                 speech_to_sil_time: int, frame_size_ms: int):
        self.window_size_ms = window_size_ms
        self.sil_to_speech_time = sil_to_speech_time
        self.speech_to_sil_time = speech_to_sil_time
        self.frame_size_ms = frame_size_ms

        self.win_size_frame = int(window_size_ms / frame_size_ms)
        self.win_sum = 0
        self.win_state = [0] * self.win_size_frame  # 初始化窗

        self.cur_win_pos = 0
        self.pre_frame_state = FrameState.kFrameStateSil
        self.cur_frame_state = FrameState.kFrameStateSil
        self.sil_to_speech_frmcnt_thres = int(sil_to_speech_time / frame_size_ms)
        self.speech_to_sil_frmcnt_thres = int(speech_to_sil_time / frame_size_ms)

        self.voice_last_frame_count = 0
        self.noise_last_frame_count = 0
        self.hydre_frame_count = 0

    def Reset(self) -> None:
        self.cur_win_pos = 0
        self.win_sum = 0
        self.win_state = [0] * self.win_size_frame
        self.pre_frame_state = FrameState.kFrameStateSil
        self.cur_frame_state = FrameState.kFrameStateSil
        self.voice_last_frame_count = 0
        self.noise_last_frame_count = 0
        self.hydre_frame_count = 0

    def GetWinSize(self) -> int:
        return int(self.win_size_frame)

    def DetectOneFrame(self, frameState: FrameState, frame_count: int) -> AudioChangeState:
        cur_frame_state = FrameState.kFrameStateSil
        if frameState == FrameState.kFrameStateSpeech:
            cur_frame_state = 1
        elif frameState == FrameState.kFrameStateSil:
            cur_frame_state = 0
        else:
            return AudioChangeState.kChangeStateInvalid
        self.win_sum -= self.win_state[self.cur_win_pos]
        self.win_sum += cur_frame_state
        self.win_state[self.cur_win_pos] = cur_frame_state
        self.cur_win_pos = (self.cur_win_pos + 1) % self.win_size_frame

        if self.pre_frame_state == FrameState.kFrameStateSil and self.win_sum >= self.sil_to_speech_frmcnt_thres:
            self.pre_frame_state = FrameState.kFrameStateSpeech
            return AudioChangeState.kChangeStateSil2Speech

        if self.pre_frame_state == FrameState.kFrameStateSpeech and self.win_sum <= self.speech_to_sil_frmcnt_thres:
            self.pre_frame_state = FrameState.kFrameStateSil
            return AudioChangeState.kChangeStateSpeech2Sil

        if self.pre_frame_state == FrameState.kFrameStateSil:
            return AudioChangeState.kChangeStateSil2Sil
        if self.pre_frame_state == FrameState.kFrameStateSpeech:
            return AudioChangeState.kChangeStateSpeech2Speech
        return AudioChangeState.kChangeStateInvalid

    def FrameSizeMs(self) -> int:
        return int(self.frame_size_ms)


class E2EVadModel(nn.Module):
    def __init__(self, encoder: FSMN, vad_post_args: Dict[str, Any]):
        super(E2EVadModel, self).__init__()
        self.vad_opts = VADXOptions(**vad_post_args)
        self.windows_detector = WindowDetector(self.vad_opts.window_size_ms,
                                               self.vad_opts.sil_to_speech_time_thres,
                                               self.vad_opts.speech_to_sil_time_thres,
                                               self.vad_opts.frame_in_ms)
        self.encoder = encoder
        # init variables
        self.is_final_send = False
        self.data_buf_start_frame = 0
        self.frm_cnt = 0
        self.latest_confirmed_speech_frame = 0
        self.lastest_confirmed_silence_frame = -1
        self.continous_silence_frame_count = 0
        self.vad_state_machine = VadStateMachine.kVadInStateStartPointNotDetected
        self.confirmed_start_frame = -1
        self.confirmed_end_frame = -1
        self.number_end_time_detected = 0
        self.sil_frame = 0
        self.sil_pdf_ids = self.vad_opts.sil_pdf_ids
        self.noise_average_decibel = -100.0
        self.pre_end_silence_detected = False

        self.output_data_buf = []
        self.output_data_buf_offset = 0
        self.frame_probs = []
        self.max_end_sil_frame_cnt_thresh = self.vad_opts.max_end_silence_time - self.vad_opts.speech_to_sil_time_thres
        self.speech_noise_thres = self.vad_opts.speech_noise_thres
        self.scores = None
        self.max_time_out = False
        self.decibel = []
        self.data_buf = None
        self.data_buf_all = None
        self.waveform = None
        self.ResetDetection()

    def AllResetDetection(self):
        self.encoder.cache_reset()  # reset the in_cache in self.encoder for next query or next long sentence
        self.is_final_send = False
        self.data_buf_start_frame = 0
        self.frm_cnt = 0
        self.latest_confirmed_speech_frame = 0
        self.lastest_confirmed_silence_frame = -1
        self.continous_silence_frame_count = 0
        self.vad_state_machine = VadStateMachine.kVadInStateStartPointNotDetected
        self.confirmed_start_frame = -1
        self.confirmed_end_frame = -1
        self.number_end_time_detected = 0
        self.sil_frame = 0
        self.sil_pdf_ids = self.vad_opts.sil_pdf_ids
        self.noise_average_decibel = -100.0
        self.pre_end_silence_detected = False

        self.output_data_buf = []
        self.output_data_buf_offset = 0
        self.frame_probs = []
        self.max_end_sil_frame_cnt_thresh = self.vad_opts.max_end_silence_time - self.vad_opts.speech_to_sil_time_thres
        self.speech_noise_thres = self.vad_opts.speech_noise_thres
        self.scores = None
        self.max_time_out = False
        self.decibel = []
        self.data_buf = None
        self.data_buf_all = None
        self.waveform = None
        self.ResetDetection()

    def ResetDetection(self):
        self.continous_silence_frame_count = 0
        self.latest_confirmed_speech_frame = 0
        self.lastest_confirmed_silence_frame = -1
        self.confirmed_start_frame = -1
        self.confirmed_end_frame = -1
        self.vad_state_machine = VadStateMachine.kVadInStateStartPointNotDetected
        self.windows_detector.Reset()
        self.sil_frame = 0
        self.frame_probs = []

    def ComputeDecibel(self) -> None:
        frame_sample_length = int(self.vad_opts.frame_length_ms * self.vad_opts.sample_rate / 1000)
        frame_shift_length = int(self.vad_opts.frame_in_ms * self.vad_opts.sample_rate / 1000)
        if self.data_buf_all is None:
            self.data_buf_all = self.waveform[0]  # self.data_buf is pointed to self.waveform[0]
            self.data_buf = self.data_buf_all
        else:
            self.data_buf_all = torch.cat((self.data_buf_all, self.waveform[0]))
        for offset in range(0, self.waveform.shape[1] - frame_sample_length + 1, frame_shift_length):
            self.decibel.append(
                10 * math.log10((self.waveform[0][offset: offset + frame_sample_length]).square().sum() + \
                                0.000001))

    def ComputeScores(self, feats: torch.Tensor) -> None:
        scores = self.encoder(feats)  # return B * T * D
        assert scores.shape[1] == feats.shape[1], "The shape between feats and scores does not match"
        self.vad_opts.nn_eval_block_size = scores.shape[1]
        self.frm_cnt += scores.shape[1]  # count total frames
        if self.scores is None:
            self.scores = scores  # the first calculation
        else:
            self.scores = torch.cat((self.scores, scores), dim=1)

    def PopDataBufTillFrame(self, frame_idx: int) -> None:  # need check again
        while self.data_buf_start_frame < frame_idx:
            if len(self.data_buf) >= int(self.vad_opts.frame_in_ms * self.vad_opts.sample_rate / 1000):
                self.data_buf_start_frame += 1
                self.data_buf = self.data_buf_all[self.data_buf_start_frame * int(
                    self.vad_opts.frame_in_ms * self.vad_opts.sample_rate / 1000):]

    def PopDataToOutputBuf(self, start_frm: int, frm_cnt: int, first_frm_is_start_point: bool,
                           last_frm_is_end_point: bool, end_point_is_sent_end: bool) -> None:
        self.PopDataBufTillFrame(start_frm)
        expected_sample_number = int(frm_cnt * self.vad_opts.sample_rate * self.vad_opts.frame_in_ms / 1000)
        if last_frm_is_end_point:
            extra_sample = max(0, int(self.vad_opts.frame_length_ms * self.vad_opts.sample_rate / 1000 - \
                               self.vad_opts.sample_rate * self.vad_opts.frame_in_ms / 1000))
            expected_sample_number += int(extra_sample)
        if end_point_is_sent_end:
            expected_sample_number = max(expected_sample_number, len(self.data_buf))
        if len(self.data_buf) < expected_sample_number:
            print('error in calling pop data_buf\n')

        if len(self.output_data_buf) == 0 or first_frm_is_start_point:
            self.output_data_buf.append(E2EVadSpeechBufWithDoa())
            self.output_data_buf[-1].Reset()
            self.output_data_buf[-1].start_ms = start_frm * self.vad_opts.frame_in_ms
            self.output_data_buf[-1].end_ms = self.output_data_buf[-1].start_ms
            self.output_data_buf[-1].doa = 0
        cur_seg = self.output_data_buf[-1]
        if cur_seg.end_ms != start_frm * self.vad_opts.frame_in_ms:
            print('warning\n')
        out_pos = len(cur_seg.buffer)  # cur_seg.buff现在没做任何操作
        data_to_pop = 0
        if end_point_is_sent_end:
            data_to_pop = expected_sample_number
        else:
            data_to_pop = int(frm_cnt * self.vad_opts.frame_in_ms * self.vad_opts.sample_rate / 1000)
        if data_to_pop > len(self.data_buf):
            print('VAD data_to_pop is bigger than self.data_buf.size()!!!\n')
            data_to_pop = len(self.data_buf)
            expected_sample_number = len(self.data_buf)

        cur_seg.doa = 0
        for sample_cpy_out in range(0, data_to_pop):
            # cur_seg.buffer[out_pos ++] = data_buf_.back();
            out_pos += 1
        for sample_cpy_out in range(data_to_pop, expected_sample_number):
            # cur_seg.buffer[out_pos++] = data_buf_.back()
            out_pos += 1
        if cur_seg.end_ms != start_frm * self.vad_opts.frame_in_ms:
            print('Something wrong with the VAD algorithm\n')
        self.data_buf_start_frame += frm_cnt
        cur_seg.end_ms = (start_frm + frm_cnt) * self.vad_opts.frame_in_ms
        if first_frm_is_start_point:
            cur_seg.contain_seg_start_point = True
        if last_frm_is_end_point:
            cur_seg.contain_seg_end_point = True

    def OnSilenceDetected(self, valid_frame: int):
        self.lastest_confirmed_silence_frame = valid_frame
        if self.vad_state_machine == VadStateMachine.kVadInStateStartPointNotDetected:
            self.PopDataBufTillFrame(valid_frame)
        # silence_detected_callback_
        # pass

    def OnVoiceDetected(self, valid_frame: int) -> None:
        self.latest_confirmed_speech_frame = valid_frame
        self.PopDataToOutputBuf(valid_frame, 1, False, False, False)

    def OnVoiceStart(self, start_frame: int, fake_result: bool = False) -> None:
        if self.vad_opts.do_start_point_detection:
            pass
        if self.confirmed_start_frame != -1:
            print('not reset vad properly\n')
        else:
            self.confirmed_start_frame = start_frame

        if not fake_result and self.vad_state_machine == VadStateMachine.kVadInStateStartPointNotDetected:
            self.PopDataToOutputBuf(self.confirmed_start_frame, 1, True, False, False)

    def OnVoiceEnd(self, end_frame: int, fake_result: bool, is_last_frame: bool) -> None:
        for t in range(self.latest_confirmed_speech_frame + 1, end_frame):
            self.OnVoiceDetected(t)
        if self.vad_opts.do_end_point_detection:
            pass
        if self.confirmed_end_frame != -1:
            print('not reset vad properly\n')
        else:
            self.confirmed_end_frame = end_frame
        if not fake_result:
            self.sil_frame = 0
            self.PopDataToOutputBuf(self.confirmed_end_frame, 1, False, True, is_last_frame)
        self.number_end_time_detected += 1

    def MaybeOnVoiceEndIfLastFrame(self, is_final_frame: bool, cur_frm_idx: int) -> None:
        if is_final_frame:
            self.OnVoiceEnd(cur_frm_idx, False, True)
            self.vad_state_machine = VadStateMachine.kVadInStateEndPointDetected

    def GetLatency(self) -> int:
        return int(self.LatencyFrmNumAtStartPoint() * self.vad_opts.frame_in_ms)

    def LatencyFrmNumAtStartPoint(self) -> int:
        vad_latency = self.windows_detector.GetWinSize()
        if self.vad_opts.do_extend:
            vad_latency += int(self.vad_opts.lookback_time_start_point / self.vad_opts.frame_in_ms)
        return vad_latency

    def GetFrameState(self, t: int) -> FrameState:
        frame_state = FrameState.kFrameStateInvalid
        cur_decibel = self.decibel[t]
        cur_snr = cur_decibel - self.noise_average_decibel
        # for each frame, calc log posterior probability of each state
        if cur_decibel < self.vad_opts.decibel_thres:
            frame_state = FrameState.kFrameStateSil
            self.DetectOneFrame(frame_state, t, False)
            return frame_state

        sum_score = 0.0
        noise_prob = 0.0
        assert len(self.sil_pdf_ids) == self.vad_opts.silence_pdf_num
        if len(self.sil_pdf_ids) > 0:
            assert len(self.scores) == 1  # 只支持batch_size = 1的测试
            sil_pdf_scores = [self.scores[0][t][sil_pdf_id] for sil_pdf_id in self.sil_pdf_ids]
            sum_score = sum(sil_pdf_scores)
            noise_prob = math.log(sum_score) * self.vad_opts.speech_2_noise_ratio
            total_score = 1.0
            sum_score = total_score - sum_score
        speech_prob = math.log(sum_score)
        if self.vad_opts.output_frame_probs:
            frame_prob = E2EVadFrameProb()
            frame_prob.noise_prob = noise_prob
            frame_prob.speech_prob = speech_prob
            frame_prob.score = sum_score
            frame_prob.frame_id = t
            self.frame_probs.append(frame_prob)
        if math.exp(speech_prob) >= math.exp(noise_prob) + self.speech_noise_thres:
            if cur_snr >= self.vad_opts.snr_thres and cur_decibel >= self.vad_opts.decibel_thres:
                frame_state = FrameState.kFrameStateSpeech
            else:
                frame_state = FrameState.kFrameStateSil
        else:
            frame_state = FrameState.kFrameStateSil
            if self.noise_average_decibel < -99.9:
                self.noise_average_decibel = cur_decibel
            else:
                self.noise_average_decibel = (cur_decibel + self.noise_average_decibel * (
                        self.vad_opts.noise_frame_num_used_for_snr
                        - 1)) / self.vad_opts.noise_frame_num_used_for_snr

        return frame_state

    def forward(self, feats: torch.Tensor, waveform: torch.tensor, is_final_send: bool = False) -> List[List[List[int]]]:
        self.waveform = waveform  # compute decibel for each frame
        self.ComputeDecibel()
        self.ComputeScores(feats)
        if not is_final_send:
            self.DetectCommonFrames()
        else:
            self.DetectLastFrames()
        segments = []
        for batch_num in range(0, feats.shape[0]):  # only support batch_size = 1 now
            segment_batch = []
            if len(self.output_data_buf) > 0:
                for i in range(self.output_data_buf_offset, len(self.output_data_buf)):
                    if self.output_data_buf[i].contain_seg_start_point and self.output_data_buf[
                        i].contain_seg_end_point:
                        segment = [self.output_data_buf[i].start_ms, self.output_data_buf[i].end_ms]
                        segment_batch.append(segment)
                        self.output_data_buf_offset += 1  # need update this parameter
            if segment_batch:
                segments.append(segment_batch)
        if is_final_send:
            self.AllResetDetection() 
        return segments

    def DetectCommonFrames(self) -> int:
        if self.vad_state_machine == VadStateMachine.kVadInStateEndPointDetected:
            return 0
        for i in range(self.vad_opts.nn_eval_block_size - 1, -1, -1):
            frame_state = FrameState.kFrameStateInvalid
            frame_state = self.GetFrameState(self.frm_cnt - 1 - i)
            self.DetectOneFrame(frame_state, self.frm_cnt - 1 - i, False)

        return 0

    def DetectLastFrames(self) -> int:
        if self.vad_state_machine == VadStateMachine.kVadInStateEndPointDetected:
            return 0
        for i in range(self.vad_opts.nn_eval_block_size - 1, -1, -1):
            frame_state = FrameState.kFrameStateInvalid
            frame_state = self.GetFrameState(self.frm_cnt - 1 - i)
            if i != 0:
                self.DetectOneFrame(frame_state, self.frm_cnt - 1 - i, False)
            else:
                self.DetectOneFrame(frame_state, self.frm_cnt - 1, True)

        return 0

    def DetectOneFrame(self, cur_frm_state: FrameState, cur_frm_idx: int, is_final_frame: bool) -> None:
        tmp_cur_frm_state = FrameState.kFrameStateInvalid
        if cur_frm_state == FrameState.kFrameStateSpeech:
            if math.fabs(1.0) > self.vad_opts.fe_prior_thres:
                tmp_cur_frm_state = FrameState.kFrameStateSpeech
            else:
                tmp_cur_frm_state = FrameState.kFrameStateSil
        elif cur_frm_state == FrameState.kFrameStateSil:
            tmp_cur_frm_state = FrameState.kFrameStateSil
        state_change = self.windows_detector.DetectOneFrame(tmp_cur_frm_state, cur_frm_idx)
        frm_shift_in_ms = self.vad_opts.frame_in_ms
        if AudioChangeState.kChangeStateSil2Speech == state_change:
            silence_frame_count = self.continous_silence_frame_count
            self.continous_silence_frame_count = 0
            self.pre_end_silence_detected = False
            start_frame = 0
            if self.vad_state_machine == VadStateMachine.kVadInStateStartPointNotDetected:
                start_frame = max(self.data_buf_start_frame, cur_frm_idx - self.LatencyFrmNumAtStartPoint())
                self.OnVoiceStart(start_frame)
                self.vad_state_machine = VadStateMachine.kVadInStateInSpeechSegment
                for t in range(start_frame + 1, cur_frm_idx + 1):
                    self.OnVoiceDetected(t)
            elif self.vad_state_machine == VadStateMachine.kVadInStateInSpeechSegment:
                for t in range(self.latest_confirmed_speech_frame + 1, cur_frm_idx):
                    self.OnVoiceDetected(t)
                if cur_frm_idx - self.confirmed_start_frame + 1 > \
                        self.vad_opts.max_single_segment_time / frm_shift_in_ms:
                    self.OnVoiceEnd(cur_frm_idx, False, False)
                    self.vad_state_machine = VadStateMachine.kVadInStateEndPointDetected
                elif not is_final_frame:
                    self.OnVoiceDetected(cur_frm_idx)
                else:
                    self.MaybeOnVoiceEndIfLastFrame(is_final_frame, cur_frm_idx)
            else:
                pass
        elif AudioChangeState.kChangeStateSpeech2Sil == state_change:
            self.continous_silence_frame_count = 0
            if self.vad_state_machine == VadStateMachine.kVadInStateStartPointNotDetected:
                pass
            elif self.vad_state_machine == VadStateMachine.kVadInStateInSpeechSegment:
                if cur_frm_idx - self.confirmed_start_frame + 1 > \
                        self.vad_opts.max_single_segment_time / frm_shift_in_ms:
                    self.OnVoiceEnd(cur_frm_idx, False, False)
                    self.vad_state_machine = VadStateMachine.kVadInStateEndPointDetected
                elif not is_final_frame:
                    self.OnVoiceDetected(cur_frm_idx)
                else:
                    self.MaybeOnVoiceEndIfLastFrame(is_final_frame, cur_frm_idx)
            else:
                pass
        elif AudioChangeState.kChangeStateSpeech2Speech == state_change:
            self.continous_silence_frame_count = 0
            if self.vad_state_machine == VadStateMachine.kVadInStateInSpeechSegment:
                if cur_frm_idx - self.confirmed_start_frame + 1 > \
                        self.vad_opts.max_single_segment_time / frm_shift_in_ms:
                    self.max_time_out = True
                    self.OnVoiceEnd(cur_frm_idx, False, False)
                    self.vad_state_machine = VadStateMachine.kVadInStateEndPointDetected
                elif not is_final_frame:
                    self.OnVoiceDetected(cur_frm_idx)
                else:
                    self.MaybeOnVoiceEndIfLastFrame(is_final_frame, cur_frm_idx)
            else:
                pass
        elif AudioChangeState.kChangeStateSil2Sil == state_change:
            self.continous_silence_frame_count += 1
            if self.vad_state_machine == VadStateMachine.kVadInStateStartPointNotDetected:
                # silence timeout, return zero length decision
                if ((self.vad_opts.detect_mode == VadDetectMode.kVadSingleUtteranceDetectMode.value) and (
                        self.continous_silence_frame_count * frm_shift_in_ms > self.vad_opts.max_start_silence_time)) \
                        or (is_final_frame and self.number_end_time_detected == 0):
                    for t in range(self.lastest_confirmed_silence_frame + 1, cur_frm_idx):
                        self.OnSilenceDetected(t)
                    self.OnVoiceStart(0, True)
                    self.OnVoiceEnd(0, True, False);
                    self.vad_state_machine = VadStateMachine.kVadInStateEndPointDetected
                else:
                    if cur_frm_idx >= self.LatencyFrmNumAtStartPoint():
                        self.OnSilenceDetected(cur_frm_idx - self.LatencyFrmNumAtStartPoint())
            elif self.vad_state_machine == VadStateMachine.kVadInStateInSpeechSegment:
                if self.continous_silence_frame_count * frm_shift_in_ms >= self.max_end_sil_frame_cnt_thresh:
                    lookback_frame = int(self.max_end_sil_frame_cnt_thresh / frm_shift_in_ms)
                    if self.vad_opts.do_extend:
                        lookback_frame -= int(self.vad_opts.lookahead_time_end_point / frm_shift_in_ms)
                        lookback_frame -= 1
                        lookback_frame = max(0, lookback_frame)
                    self.OnVoiceEnd(cur_frm_idx - lookback_frame, False, False)
                    self.vad_state_machine = VadStateMachine.kVadInStateEndPointDetected
                elif cur_frm_idx - self.confirmed_start_frame + 1 > \
                        self.vad_opts.max_single_segment_time / frm_shift_in_ms:
                    self.OnVoiceEnd(cur_frm_idx, False, False)
                    self.vad_state_machine = VadStateMachine.kVadInStateEndPointDetected
                elif self.vad_opts.do_extend and not is_final_frame:
                    if self.continous_silence_frame_count <= int(
                            self.vad_opts.lookahead_time_end_point / frm_shift_in_ms):
                        self.OnVoiceDetected(cur_frm_idx)
                else:
                    self.MaybeOnVoiceEndIfLastFrame(is_final_frame, cur_frm_idx)
            else:
                pass

        if self.vad_state_machine == VadStateMachine.kVadInStateEndPointDetected and \
                self.vad_opts.detect_mode == VadDetectMode.kVadMutipleUtteranceDetectMode.value:
            self.ResetDetection()