diff --git a/examples/cpp/silero-vad-onnx.cpp b/examples/cpp/silero-vad-onnx.cpp
index 05d8aed..27fceb0 100644
--- a/examples/cpp/silero-vad-onnx.cpp
+++ b/examples/cpp/silero-vad-onnx.cpp
@@ -2,13 +2,97 @@
 #include <vector>
 #include <sstream>
 #include <cstring>
+#include <limits>
 #include <chrono>
-
+#include <memory>
+#include <string>
+#include <stdexcept>
+#include <iostream>
+#include <string>
 #include "onnxruntime_cxx_api.h"
 #include "wav.h"
+#include <cstdio>
+#include <cstdarg>
+#if __cplusplus < 201703L
+#include <memory>
+#endif
+
+//#define __DEBUG_SPEECH_PROB___
+
+class timestamp_t
+{
+public:
+    int start;
+    int end;
+
+    // default + parameterized constructor
+    timestamp_t(int start = 0, int end = 0)
+        : start(start), end(end)
+    {
+    };
+
+    // assignment operator modifies object, therefore non-const
+    timestamp_t& operator=(const timestamp_t& a)
+    {
+        start = a.start;
+        end = a.end;
+        return *this;
+    };
+
+    // equality comparison. doesn't modify object. therefore const.
+    bool operator==(const timestamp_t& a) const
+    {
+        return (start == a.start && end == a.end);
+    };
+    std::string c_str()
+    {
+        //return std::format("timestamp {:08d}, {:08d}", start, end);
+        return format("{start:%08d,end:%08d}", start, end);
+    };
+private:
+
+    std::string format(const char* fmt, ...)
+    {
+        char buf[256];
+
+        va_list args;
+        va_start(args, fmt);
+        const auto r = std::vsnprintf(buf, sizeof buf, fmt, args);
+        va_end(args);
+
+        if (r < 0)
+            // conversion failed
+            return {};
+
+        const size_t len = r;
+        if (len < sizeof buf)
+            // we fit in the buffer
+            return { buf, len };
+
+#if __cplusplus >= 201703L
+        // C++17: Create a string and write to its underlying array
+        std::string s(len, '\0');
+        va_start(args, fmt);
+        std::vsnprintf(s.data(), len + 1, fmt, args);
+        va_end(args);
+
+        return s;
+#else
+        // C++11 or C++14: We need to allocate scratch memory
+        auto vbuf = std::unique_ptr<char[]>(new char[len + 1]);
+        va_start(args, fmt);
+        std::vsnprintf(vbuf.get(), len + 1, fmt, args);
+        va_end(args);
+
+        return { vbuf.get(), len };
+#endif
+    };
+};
+
 
 class VadIterator
 {
+private:
     // OnnxRuntime resources
     Ort::Env env;
     Ort::SessionOptions session_options;
@@ -16,48 +100,40 @@ class VadIterator
     Ort::AllocatorWithDefaultOptions allocator;
     Ort::MemoryInfo memory_info = Ort::MemoryInfo::CreateCpu(OrtArenaAllocator, OrtMemTypeCPU);
 
-public:
+private:
     void init_engine_threads(int inter_threads, int intra_threads)
-    {   
+    {
         // The method should be called in each thread/proc in multi-thread/proc work
         session_options.SetIntraOpNumThreads(intra_threads);
         session_options.SetInterOpNumThreads(inter_threads);
         session_options.SetGraphOptimizationLevel(GraphOptimizationLevel::ORT_ENABLE_ALL);
-    }
+    };
 
-    void init_onnx_model(const std::string &model_path)
-    {   
+    void init_onnx_model(const std::wstring& model_path)
+    {
         // Init threads = 1 for 
         init_engine_threads(1, 1);
         // Load model
         session = std::make_shared<Ort::Session>(env, model_path.c_str(), session_options);
-    }
+    };
 
     void reset_states()
     {
         // Call reset before each audio start
         std::memset(_h.data(), 0.0f, _h.size() * sizeof(float));
         std::memset(_c.data(), 0.0f, _c.size() * sizeof(float));
-        triggerd = false;
+        triggered = false;
         temp_end = 0;
         current_sample = 0;
-    }
 
-    // Call it in predict func. if you prefer raw bytes input.
-    void bytes_to_float_tensor(const char *pcm_bytes) 
-    {
-        const int16_t * in_data = reinterpret_cast<const int16_t*>(pcm_bytes);
-        for (int i = 0; i < window_size_samples; i++)
-        {
-            input[i] = static_cast<float>(in_data[i]) / 32768; // int16_t normalized to float
-        }
-    }
+        prev_end = next_start = 0;
 
+        speeches.clear();
+        current_speech = timestamp_t(0, 0);
+    };
 
     void predict(const std::vector<float> &data)
     {
-        // bytes_to_float_tensor(data); 
-        
         // Infer
         // Create ort tensors
         input.assign(data.begin(), data.end());
@@ -84,7 +160,7 @@ public:
             output_node_names.data(), output_node_names.size());
 
         // Output probability & update h,c recursively
-        float output = ort_outputs[0].GetTensorMutableData<float>()[0];
+        float speech_prob = ort_outputs[0].GetTensorMutableData<float>()[0];
         float *hn = ort_outputs[1].GetTensorMutableData<float>();
         std::memcpy(_h.data(), hn, size_hc * sizeof(float));
         float *cn = ort_outputs[2].GetTensorMutableData<float>();
@@ -92,75 +168,209 @@ public:
 
         // Push forward sample index
         current_sample += window_size_samples;
-        
+
         // Reset temp_end when > threshold 
-        if ((output >= threshold) && (temp_end != 0))
+        if ((speech_prob >= threshold))
         {
-            temp_end = 0;
-        }
-        // 1) Silence
-        if ((output < threshold) && (triggerd == false))
-        {
-            // printf("{ silence: %.3f s }\n", 1.0 * current_sample / sample_rate);
-        }
-        // 2) Speaking 
-        if ((output >= (threshold - 0.15)) && (triggerd == true))
-        {
-            // printf("{ speaking_2: %.3f s }\n", 1.0 * current_sample / sample_rate);
+#ifdef __DEBUG_SPEECH_PROB___
+            float speech = current_sample - window_size_samples; // minus window_size_samples to get precise start time point.
+            printf("{    start: %.3f s (%.3f) %08d}\n", 1.0 * speech / sample_rate, speech_prob, current_sample- window_size_samples);
+#endif //__DEBUG_SPEECH_PROB___
+            if (temp_end != 0)
+            {
+                temp_end = 0;
+                if (next_start < prev_end)
+                    next_start = current_sample - window_size_samples;
+            }
+            if (triggered == false)
+            {
+                triggered = true;
+
+                current_speech.start = current_sample - window_size_samples;
+            }
+            return;
         }
 
-        // 3) Start
-        if ((output >= threshold) && (triggerd == false))
-        {
-            triggerd = true;
-            speech_start = current_sample - window_size_samples - speech_pad_samples; // minus window_size_samples to get precise start time point.
-            printf("{ start: %.3f s }\n", 1.0 * speech_start / sample_rate);
+        if (
+            (triggered == true)
+            && ((current_sample - current_speech.start) > max_speech_samples)
+            ) {
+            if (prev_end > 0) {
+                current_speech.end = prev_end;
+                speeches.push_back(current_speech);
+                current_speech = timestamp_t(0, 0);
+                
+                // previously reached silence(< neg_thres) and is still not speech(< thres)
+                if (next_start < prev_end)
+                    triggered = false;
+                else{
+                    current_speech.start = next_start;
+                }
+                prev_end = 0;
+                next_start = 0;
+                temp_end = 0;
+
+            }
+            else{ 
+                current_speech.end = current_sample;
+                speeches.push_back(current_speech);
+                current_speech = timestamp_t(0, 0);
+                prev_end = 0;
+                next_start = 0;
+                temp_end = 0;
+                triggered = false;
+            }
+            return;
+
         }
+        if ((speech_prob >= (threshold - 0.15)) && (speech_prob < threshold))
+        {
+            if (triggered) {
+#ifdef __DEBUG_SPEECH_PROB___
+                float speech = current_sample - window_size_samples; // minus window_size_samples to get precise start time point.
+                printf("{ speeking: %.3f s (%.3f) %08d}\n", 1.0 * speech / sample_rate, speech_prob, current_sample - window_size_samples);
+#endif //__DEBUG_SPEECH_PROB___
+            }
+            else {
+#ifdef __DEBUG_SPEECH_PROB___
+                float speech = current_sample - window_size_samples; // minus window_size_samples to get precise start time point.
+                printf("{  silence: %.3f s (%.3f) %08d}\n", 1.0 * speech / sample_rate, speech_prob, current_sample - window_size_samples);
+#endif //__DEBUG_SPEECH_PROB___
+            }
+            return;
+        }
+
 
         // 4) End 
-        if ((output < (threshold - 0.15)) && (triggerd == true))
+        if ((speech_prob < (threshold - 0.15)))
         {
+#ifdef __DEBUG_SPEECH_PROB___
+            float speech = current_sample - window_size_samples - speech_pad_samples; // minus window_size_samples to get precise start time point.
+            printf("{      end: %.3f s (%.3f) %08d}\n", 1.0 * speech / sample_rate, speech_prob, current_sample - window_size_samples);
+#endif //__DEBUG_SPEECH_PROB___
+            if (triggered == true)
+            {
+                if (temp_end == 0)
+                {
+                    temp_end = current_sample;
+                }
+                if (current_sample - temp_end > min_silence_samples_at_max_speech)
+                    prev_end = temp_end;
+                // a. silence < min_slience_samples, continue speaking 
+                if ((current_sample - temp_end) < min_silence_samples)
+                {
 
-            if (temp_end == 0)
-            {
-                temp_end = current_sample;
+                }
+                // b. silence >= min_slience_samples, end speaking
+                else
+                {
+                    current_speech.end = temp_end;
+                    if (current_speech.end - current_speech.start > min_speech_samples)
+                    {
+                        speeches.push_back(current_speech);
+                        current_speech = timestamp_t(0, 0);
+                        prev_end = 0;
+                        next_start = 0;
+                        temp_end = 0;
+                        triggered = false;
+                    }
+                }
             }
-            // a. silence < min_slience_samples, continue speaking 
-            if ((current_sample - temp_end) < min_silence_samples)
-            {
-                // printf("{ speaking_4: %.3f s }\n", 1.0 * current_sample / sample_rate);
-                // printf("");
-            }
-            // b. silence >= min_slience_samples, end speaking
-            else
-            {
-                speech_end = temp_end ? temp_end + speech_pad_samples : current_sample + speech_pad_samples;
-                temp_end = 0;
-                triggerd = false;
-                printf("{ end: %.3f s }\n", 1.0 * speech_end / sample_rate);
+            else {
+                // may first windows see end state.
             }
+            return;
+        }
+    };
+public:
+    void process(const std::vector<float>& input_wav)
+    {
+        reset_states();
+
+        audio_length_samples = input_wav.size();
+
+        for (int j = 0; j < audio_length_samples; j += window_size_samples)
+        {
+            if (j + window_size_samples > audio_length_samples)
+                break;
+            std::vector<float> r{ &input_wav[0] + j, &input_wav[0] + j + window_size_samples };
+            predict(r);
         }
 
+        if (current_speech.start > 0) {
+            current_speech.end = audio_length_samples;
+            speeches.push_back(current_speech);
+            current_speech = timestamp_t(0, 0);
+            prev_end = 0;
+            next_start = 0;
+            temp_end = 0;
+            triggered = false;
+        }
+    };
 
+    void process(const std::vector<float>& input_wav, std::vector<float>& output_wav)
+    {
+        process(input_wav);
+        collect_chunks(input_wav, output_wav);
     }
 
+    void collect_chunks(const std::vector<float>& input_wav, std::vector<float>& output_wav)
+    {
+        output_wav.clear();
+        for (int i = 0; i < speeches.size(); i++) {
+#ifdef __DEBUG_SPEECH_PROB___
+            std::cout << speeches[i].c_str() << std::endl;
+#endif //#ifdef __DEBUG_SPEECH_PROB___
+            std::vector<float> slice(&input_wav[speeches[i].start], &input_wav[speeches[i].end]);
+            output_wav.insert(output_wav.end(),slice.begin(),slice.end());
+        }
+    };
+
+    const std::vector<timestamp_t> get_speech_timestamps() const
+    {
+        return speeches;
+    }
+
+    void drop_chunks(const std::vector<float>& input_wav, std::vector<float>& output_wav)
+    {
+        output_wav.clear();
+        int current_start = 0;
+        for (int i = 0; i < speeches.size(); i++) {
+
+            std::vector<float> slice(&input_wav[current_start],&input_wav[speeches[i].start]);
+            output_wav.insert(output_wav.end(), slice.begin(), slice.end());
+            current_start = speeches[i].end;
+        }
+
+        std::vector<float> slice(&input_wav[current_start], &input_wav[input_wav.size()]);
+        output_wav.insert(output_wav.end(), slice.begin(), slice.end());
+    };
+
 private:
     // model config
     int64_t window_size_samples;  // Assign when init, support 256 512 768 for 8k; 512 1024 1536 for 16k.
-    int sample_rate;
-    int sr_per_ms;  // Assign when init, support 8 or 16
-    float threshold;
+    int sample_rate;  //Assign when init support 16000 or 8000      
+    int sr_per_ms;   // Assign when init, support 8 or 16
+    float threshold; 
     int min_silence_samples; // sr_per_ms * #ms
+    int min_silence_samples_at_max_speech; // sr_per_ms * #98
+    int min_speech_samples; // sr_per_ms * #ms
+    float max_speech_samples;
     int speech_pad_samples; // usually a 
+    int audio_length_samples;
 
     // model states
-    bool triggerd = false;
-    unsigned int speech_start = 0; 
-    unsigned int speech_end = 0;
+    bool triggered = false;
     unsigned int temp_end = 0;
     unsigned int current_sample = 0;    
     // MAX 4294967295 samples / 8sample per ms / 1000 / 60 = 8947 minutes  
-    float output;
+    int prev_end;
+    int next_start = 0;
+
+    //Output timestamp
+    std::vector<timestamp_t> speeches;
+    timestamp_t current_speech;
+
 
     // Onnx model
     // Inputs
@@ -180,75 +390,97 @@ private:
     // Outputs
     std::vector<Ort::Value> ort_outputs;
     std::vector<const char *> output_node_names = {"output", "hn", "cn"};
-    
 
 public:
     // Construction
-    VadIterator(const std::string ModelPath, 
-             int Sample_rate, int frame_size, 
-             float Threshold, int min_silence_duration_ms, int speech_pad_ms) 
+    VadIterator(const std::wstring ModelPath,
+        int Sample_rate = 16000, int windows_frame_size = 64,
+        float Threshold = 0.5, int min_silence_duration_ms = 0,
+        int speech_pad_ms = 64, int min_speech_duration_ms = 64,
+        float max_speech_duration_s = std::numeric_limits<float>::infinity())
     {
         init_onnx_model(ModelPath);
+        threshold = Threshold;
         sample_rate = Sample_rate;
         sr_per_ms = sample_rate / 1000;
-        threshold = Threshold;
-        min_silence_samples = sr_per_ms * min_silence_duration_ms;
+
+        window_size_samples = windows_frame_size * sr_per_ms;
+
+        min_speech_samples = sr_per_ms * min_speech_duration_ms;
         speech_pad_samples = sr_per_ms * speech_pad_ms;
-        window_size_samples = frame_size * sr_per_ms;
-        
+
+        max_speech_samples = (
+            sample_rate * max_speech_duration_s
+            - window_size_samples
+            - 2 * speech_pad_samples
+            );
+
+        min_silence_samples = sr_per_ms * min_silence_duration_ms;
+        min_silence_samples_at_max_speech = sr_per_ms * 98;
+
         input.resize(window_size_samples);
         input_node_dims[0] = 1;
         input_node_dims[1] = window_size_samples;
-        // std::cout << "== Input size" << input.size() << std::endl;
+
         _h.resize(size_hc);
         _c.resize(size_hc);
         sr.resize(1);
         sr[0] = sample_rate;
-    }
-
+    };
 };
 
 int main()
 {
+    std::vector<timestamp_t> stamps;
 
     // Read wav
-    wav::WavReader wav_reader("./test_for_vad.wav");
-    std::vector<int16_t> data(wav_reader.num_samples());
+    wav::WavReader wav_reader("recorder.wav"); //16000,1,32float
     std::vector<float> input_wav(wav_reader.num_samples());
+    std::vector<float> output_wav;
 
     for (int i = 0; i < wav_reader.num_samples(); i++)
     {
-        data[i] = static_cast<int16_t>(*(wav_reader.data() + i));
+        input_wav[i] = static_cast<float>(*(wav_reader.data() + i));
     }
 
-    for (int i = 0; i < wav_reader.num_samples(); i++)
-    {
-        input_wav[i] = static_cast<float>(data[i]) / 32768;
-    }
+
 
     // ===== Test configs =====
-    std::string path = "../files/silero_vad.onnx";
-    int test_sr = 8000;
-    int test_frame_ms = 64;
-    float test_threshold = 0.5f;
-    int test_min_silence_duration_ms = 0;
-    int test_speech_pad_ms = 0;
-    int test_window_samples = test_frame_ms * (test_sr/1000);
+    std::wstring path = L"silero_vad.onnx";
+    VadIterator vad(path);
 
-    VadIterator vad(
-        path, test_sr, test_frame_ms, test_threshold,
-        test_min_silence_duration_ms, test_speech_pad_ms);
+    // ==============================================
+    // ==== = Example 1 of full function  ===== 
+    // ==============================================
+    vad.process(input_wav);
 
-    for (int j = 0; j < wav_reader.num_samples(); j += test_window_samples)
-    {
-        // std::cout << "== 4" << std::endl;
-        std::vector<float> r{&input_wav[0] + j, &input_wav[0] + j + test_window_samples};
-        auto start = std::chrono::high_resolution_clock::now();
-        // Predict and print throughout process time
-        vad.predict(r);
-        auto end = std::chrono::high_resolution_clock::now();
-        auto elapsed_time = std::chrono::duration_cast<std::chrono::nanoseconds>(end-start);
-        // std::cout << "== Elapsed time: " << 1.0*elapsed_time.count()/1000000 << "ms" << " ==" <<std::endl;
+    // 1.a get_speech_timestamps
+    stamps = vad.get_speech_timestamps();
+    for (int i = 0; i < stamps.size(); i++) {
 
+        std::cout << stamps[i].c_str() << std::endl;
     }
+
+    // 1.b collect_chunks output wav
+    vad.collect_chunks(input_wav, output_wav);
+
+    // 1.c drop_chunks output wav
+    vad.drop_chunks(input_wav, output_wav);
+
+    // ==============================================
+    // ===== Example 2 of simple full function  =====
+    // ==============================================
+    vad.process(input_wav, output_wav);
+
+    stamps = vad.get_speech_timestamps();
+    for (int i = 0; i < stamps.size(); i++) {
+
+        std::cout << stamps[i].c_str() << std::endl;
+    }
+
+    // ==============================================
+    // ===== Example 3 of full function  =====
+    // ==============================================
+    for(int i = 0; i<2; i++)
+        vad.process(input_wav, output_wav);
 }
diff --git a/examples/cpp/wav.h b/examples/cpp/wav.h
index 097f1c2..a3566b6 100644
--- a/examples/cpp/wav.h
+++ b/examples/cpp/wav.h
@@ -59,8 +59,7 @@ class WavReader {
     WavHeader header;
     fread(&header, 1, sizeof(header), fp);
     if (header.fmt_size < 16) {
-      fprintf(stderr,
-              "WaveData: expect PCM format data "
+      printf("WaveData: expect PCM format data "
               "to have fmt chunk of at least size 16.\n");
       return false;
     } else if (header.fmt_size > 16) {
@@ -87,6 +86,12 @@ class WavReader {
     data_ = new float[num_data]; // Create 1-dim array
     num_samples_ = num_data / num_channel_;
 
+    std::cout << "num_channel_    :" << num_channel_ << std::endl;
+    std::cout << "sample_rate_    :" << sample_rate_ << std::endl;
+    std::cout << "bits_per_sample_:" << bits_per_sample_ << std::endl;
+    std::cout << "num_samples     :" << num_data << std::endl;
+    std::cout << "num_data size   :" << header.data_size << std::endl;
+
     for (int i = 0; i < num_data; ++i) {
       switch (bits_per_sample_) {
         case 8: {
@@ -110,7 +115,7 @@ class WavReader {
           break;
         }
         default:
-          fprintf(stderr, "unsupported quantization bits");
+          printf("unsupported quantization bits\n");
           exit(1);
       }
     }