diff --git a/cxx-api-examples/parakeet-tdt-simulate-streaming-microphone-cxx-api.cc b/cxx-api-examples/parakeet-tdt-simulate-streaming-microphone-cxx-api.cc
index 9f150679..922ac158 100644
--- a/cxx-api-examples/parakeet-tdt-simulate-streaming-microphone-cxx-api.cc
+++ b/cxx-api-examples/parakeet-tdt-simulate-streaming-microphone-cxx-api.cc
@@ -116,7 +116,6 @@ int32_t main() {
   sherpa_onnx::Microphone mic;
 
   PaDeviceIndex num_devices = Pa_GetDeviceCount();
-  std::cout << "Num devices: " << num_devices << "\n";
   if (num_devices == 0) {
     std::cerr << "  If you are using Linux, please try "
                  "./build/bin/sense-voice-simulate-streaming-alsa-cxx-api\n";
@@ -124,39 +123,24 @@ int32_t main() {
   }
 
   int32_t device_index = Pa_GetDefaultInputDevice();
-
   const char *pDeviceIndex = std::getenv("SHERPA_ONNX_MIC_DEVICE");
   if (pDeviceIndex) {
     fprintf(stderr, "Use specified device: %s\n", pDeviceIndex);
     device_index = atoi(pDeviceIndex);
   }
+  mic.PrintDevices(device_index);
 
-  for (int32_t i = 0; i != num_devices; ++i) {
-    const PaDeviceInfo *info = Pa_GetDeviceInfo(i);
-    fprintf(stderr, " %s %d %s\n", (i == device_index) ? "*" : " ", i,
-            info->name);
-  }
-
-  PaStreamParameters param;
-  param.device = device_index;
-
-  fprintf(stderr, "Use device: %d\n", param.device);
-
-  const PaDeviceInfo *info = Pa_GetDeviceInfo(param.device);
-  fprintf(stderr, "  Name: %s\n", info->name);
-  fprintf(stderr, "  Max input channels: %d\n", info->maxInputChannels);
-
-  param.channelCount = 1;
-  param.sampleFormat = paFloat32;
-
-  param.suggestedLatency = info->defaultLowInputLatency;
-  param.hostApiSpecificStreamInfo = nullptr;
   float mic_sample_rate = 16000;
   const char *sample_rate_str = std::getenv("SHERPA_ONNX_MIC_SAMPLE_RATE");
   if (sample_rate_str) {
     fprintf(stderr, "Use sample rate %f for mic\n", mic_sample_rate);
     mic_sample_rate = atof(sample_rate_str);
   }
+  if(!mic.OpenDevice(device_index, mic_sample_rate, 1, RecordCallback,
+                     nullptr) == false) {
+    std::cerr << "Failed to open microphone device\n";
+    return -1;
+  }
   float sample_rate = 16000;
   LinearResampler resampler;
   if (mic_sample_rate != sample_rate) {
@@ -168,27 +152,6 @@ int32_t main() {
                                         lowpass_cutoff, lowpass_filter_width);
   }
 
-  PaStream *stream;
-  PaError err =
-      Pa_OpenStream(&stream, &param, nullptr, /* &outputParameters, */
-                    mic_sample_rate,
-                    0,               // frames per buffer
-                    paClipOff,       // we won't output out of range samples
-                                     // so don't bother clipping them
-                    RecordCallback,  // RecordCallback is run in a separate
-                                     // thread created by portaudio
-                    nullptr);
-  if (err != paNoError) {
-    fprintf(stderr, "portaudio error: %s\n", Pa_GetErrorText(err));
-    exit(EXIT_FAILURE);
-  }
-
-  err = Pa_StartStream(stream);
-  if (err != paNoError) {
-    fprintf(stderr, "portaudio error: %s\n", Pa_GetErrorText(err));
-    exit(EXIT_FAILURE);
-  }
-
   int32_t window_size = 512;  // samples, please don't change
 
   int32_t offset = 0;
@@ -276,11 +239,5 @@ int32_t main() {
     }
   }
 
-  err = Pa_CloseStream(stream);
-  if (err != paNoError) {
-    fprintf(stderr, "portaudio error: %s\n", Pa_GetErrorText(err));
-    exit(EXIT_FAILURE);
-  }
-
   return 0;
 }
diff --git a/cxx-api-examples/sense-voice-simulate-streaming-microphone-cxx-api.cc b/cxx-api-examples/sense-voice-simulate-streaming-microphone-cxx-api.cc
index 0ace2336..f1efc079 100644
--- a/cxx-api-examples/sense-voice-simulate-streaming-microphone-cxx-api.cc
+++ b/cxx-api-examples/sense-voice-simulate-streaming-microphone-cxx-api.cc
@@ -112,7 +112,6 @@ int32_t main() {
   sherpa_onnx::Microphone mic;
 
   PaDeviceIndex num_devices = Pa_GetDeviceCount();
-  std::cout << "Num devices: " << num_devices << "\n";
   if (num_devices == 0) {
     std::cerr << "  If you are using Linux, please try "
                  "./build/bin/sense-voice-simulate-streaming-alsa-cxx-api\n";
@@ -120,33 +119,13 @@ int32_t main() {
   }
 
   int32_t device_index = Pa_GetDefaultInputDevice();
-
   const char *pDeviceIndex = std::getenv("SHERPA_ONNX_MIC_DEVICE");
   if (pDeviceIndex) {
     fprintf(stderr, "Use specified device: %s\n", pDeviceIndex);
     device_index = atoi(pDeviceIndex);
   }
+  mic.PrintDevices(device_index);
 
-  for (int32_t i = 0; i != num_devices; ++i) {
-    const PaDeviceInfo *info = Pa_GetDeviceInfo(i);
-    fprintf(stderr, " %s %d %s\n", (i == device_index) ? "*" : " ", i,
-            info->name);
-  }
-
-  PaStreamParameters param;
-  param.device = device_index;
-
-  fprintf(stderr, "Use device: %d\n", param.device);
-
-  const PaDeviceInfo *info = Pa_GetDeviceInfo(param.device);
-  fprintf(stderr, "  Name: %s\n", info->name);
-  fprintf(stderr, "  Max input channels: %d\n", info->maxInputChannels);
-
-  param.channelCount = 1;
-  param.sampleFormat = paFloat32;
-
-  param.suggestedLatency = info->defaultLowInputLatency;
-  param.hostApiSpecificStreamInfo = nullptr;
   float mic_sample_rate = 16000;
   const char *sample_rate_str = std::getenv("SHERPA_ONNX_MIC_SAMPLE_RATE");
   if (sample_rate_str) {
@@ -163,26 +142,10 @@ int32_t main() {
     resampler = LinearResampler::Create(mic_sample_rate, sample_rate,
                                         lowpass_cutoff, lowpass_filter_width);
   }
-
-  PaStream *stream;
-  PaError err =
-      Pa_OpenStream(&stream, &param, nullptr, /* &outputParameters, */
-                    mic_sample_rate,
-                    0,               // frames per buffer
-                    paClipOff,       // we won't output out of range samples
-                                     // so don't bother clipping them
-                    RecordCallback,  // RecordCallback is run in a separate
-                                     // thread created by portaudio
-                    nullptr);
-  if (err != paNoError) {
-    fprintf(stderr, "portaudio error: %s\n", Pa_GetErrorText(err));
-    exit(EXIT_FAILURE);
-  }
-
-  err = Pa_StartStream(stream);
-  if (err != paNoError) {
-    fprintf(stderr, "portaudio error: %s\n", Pa_GetErrorText(err));
-    exit(EXIT_FAILURE);
+  if (mic.OpenDevice(device_index, mic_sample_rate, 1, RecordCallback,
+                    nullptr) == false) {
+    std::cerr << "Failed to open microphone device\n";
+    return -1;
   }
 
   int32_t window_size = 512;  // samples, please don't change
@@ -272,11 +235,5 @@ int32_t main() {
     }
   }
 
-  err = Pa_CloseStream(stream);
-  if (err != paNoError) {
-    fprintf(stderr, "portaudio error: %s\n", Pa_GetErrorText(err));
-    exit(EXIT_FAILURE);
-  }
-
   return 0;
 }
diff --git a/sherpa-onnx/csrc/microphone.cc b/sherpa-onnx/csrc/microphone.cc
index 956574f4..2fd71d1e 100644
--- a/sherpa-onnx/csrc/microphone.cc
+++ b/sherpa-onnx/csrc/microphone.cc
@@ -7,8 +7,6 @@
 #include <stdio.h>
 #include <stdlib.h>
 
-#include "portaudio.h"  // NOLINT
-
 namespace sherpa_onnx {
 
 Microphone::Microphone() {
@@ -20,10 +18,85 @@ Microphone::Microphone() {
 }
 
 Microphone::~Microphone() {
+  CloseDevice();
   PaError err = Pa_Terminate();
   if (err != paNoError) {
     fprintf(stderr, "portaudio error: %s\n", Pa_GetErrorText(err));
-    exit(-1);
+  }
+}
+
+int Microphone::GetDeviceCount() const {
+  return Pa_GetDeviceCount();
+}
+
+int Microphone::GetDefaultInputDevice() const {
+  return Pa_GetDefaultInputDevice();
+}
+
+void Microphone::PrintDevices(int device_index) const {
+  PaDeviceIndex num_devices = Pa_GetDeviceCount();
+  fprintf(stderr, "Num devices: %d\n", num_devices);
+  for (int32_t i = 0; i != num_devices; ++i) {
+    const PaDeviceInfo *info = Pa_GetDeviceInfo(i);
+    fprintf(stderr, " %s %d %s\n", (i == device_index) ? "*" : " ", i,
+            info->name);
+  }
+}
+
+bool Microphone::OpenDevice(int index, int sample_rate, int channel, PaStreamCallback cb, void* userdata) {
+  if (index < 0 || index >= Pa_GetDeviceCount()) {
+    fprintf(stderr, "Invalid device index: %d\n", index);
+    return false;
+  }
+
+  const PaDeviceInfo *info = Pa_GetDeviceInfo(index);
+  if (!info) {
+    fprintf(stderr, "No device info found for index: %d\n", index);
+    return false;
+  }
+
+  CloseDevice();
+
+  fprintf(stderr, "Use device: %d\n", index);
+  fprintf(stderr, "  Name: %s\n", info->name);
+  fprintf(stderr, "  Max input channels: %d\n", info->maxInputChannels);
+
+  PaStreamParameters param;
+  param.device = index;
+  param.channelCount = channel;
+  param.sampleFormat = paFloat32;
+  param.suggestedLatency = info->defaultLowInputLatency;
+  param.hostApiSpecificStreamInfo = nullptr;
+
+  PaError err = Pa_OpenStream(&stream, &param, nullptr, /* &outputParameters, */
+                    sample_rate,
+                    0,          // frames per buffer
+                    paClipOff,  // we won't output out of range samples
+                                // so don't bother clipping them
+                    cb, userdata);
+  if (err != paNoError) {
+    fprintf(stderr, "portaudio error: %s\n", Pa_GetErrorText(err));
+    return false;
+  }
+
+  err = Pa_StartStream(stream);
+  fprintf(stderr, "Started\n");
+
+  if (err != paNoError) {
+    fprintf(stderr, "portaudio error: %s\n", Pa_GetErrorText(err));
+    CloseDevice();
+    return false;
+  }
+  return true;
+}
+
+void Microphone::CloseDevice() {
+  if (stream) {
+    PaError err = Pa_CloseStream(stream);
+    if (err != paNoError) {
+      fprintf(stderr, "Pa_CloseStream error: %s\n", Pa_GetErrorText(err));
+    }
+    stream = nullptr;
   }
 }
 
diff --git a/sherpa-onnx/csrc/microphone.h b/sherpa-onnx/csrc/microphone.h
index 61cedbf3..8d651793 100644
--- a/sherpa-onnx/csrc/microphone.h
+++ b/sherpa-onnx/csrc/microphone.h
@@ -4,13 +4,22 @@
 
 #ifndef SHERPA_ONNX_CSRC_MICROPHONE_H_
 #define SHERPA_ONNX_CSRC_MICROPHONE_H_
+#include "portaudio.h"  // NOLINT
 
 namespace sherpa_onnx {
 
 class Microphone {
+  PaStream *stream = nullptr;
  public:
   Microphone();
   ~Microphone();
+
+  int GetDeviceCount() const;
+  int GetDefaultInputDevice() const;
+  void PrintDevices(int sel) const;
+  
+  bool OpenDevice(int index, int sample_rate, int channel, PaStreamCallback cb, void* userdata);
+  void CloseDevice();
 };
 
 }  // namespace sherpa_onnx
diff --git a/sherpa-onnx/csrc/sherpa-onnx-alsa-offline-speaker-identification.cc b/sherpa-onnx/csrc/sherpa-onnx-alsa-offline-speaker-identification.cc
index da00ea62..a14ff5c7 100644
--- a/sherpa-onnx/csrc/sherpa-onnx-alsa-offline-speaker-identification.cc
+++ b/sherpa-onnx/csrc/sherpa-onnx-alsa-offline-speaker-identification.cc
@@ -14,7 +14,6 @@
 
 #include "sherpa-onnx/csrc/alsa.h"
 #include "sherpa-onnx/csrc/macros.h"
-#include "sherpa-onnx/csrc/microphone.h"
 #include "sherpa-onnx/csrc/speaker-embedding-extractor.h"
 #include "sherpa-onnx/csrc/speaker-embedding-manager.h"
 #include "sherpa-onnx/csrc/wave-reader.h"
diff --git a/sherpa-onnx/csrc/sherpa-onnx-keyword-spotter-microphone.cc b/sherpa-onnx/csrc/sherpa-onnx-keyword-spotter-microphone.cc
index 4d75f9d4..4eed37c4 100644
--- a/sherpa-onnx/csrc/sherpa-onnx-keyword-spotter-microphone.cc
+++ b/sherpa-onnx/csrc/sherpa-onnx-keyword-spotter-microphone.cc
@@ -79,11 +79,7 @@ for a list of pre-trained models to download.
 
   sherpa_onnx::Microphone mic;
 
-  PaDeviceIndex num_devices = Pa_GetDeviceCount();
-  fprintf(stderr, "Num devices: %d\n", num_devices);
-
   int32_t device_index = Pa_GetDefaultInputDevice();
-
   if (device_index == paNoDevice) {
     fprintf(stderr, "No default input device found\n");
     fprintf(stderr, "If you are using Linux, please switch to \n");
@@ -97,26 +93,7 @@ for a list of pre-trained models to download.
     device_index = atoi(pDeviceIndex);
   }
 
-  for (int32_t i = 0; i != num_devices; ++i) {
-    const PaDeviceInfo *info = Pa_GetDeviceInfo(i);
-    fprintf(stderr, " %s %d %s\n", (i == device_index) ? "*" : " ", i,
-            info->name);
-  }
-
-  PaStreamParameters param;
-  param.device = device_index;
-
-  fprintf(stderr, "Use device: %d\n", param.device);
-
-  const PaDeviceInfo *info = Pa_GetDeviceInfo(param.device);
-  fprintf(stderr, "  Name: %s\n", info->name);
-  fprintf(stderr, "  Max input channels: %d\n", info->maxInputChannels);
-
-  param.channelCount = 1;
-  param.sampleFormat = paFloat32;
-
-  param.suggestedLatency = info->defaultLowInputLatency;
-  param.hostApiSpecificStreamInfo = nullptr;
+  mic.PrintDevices(device_index);
 
   const char *pSampleRateStr = std::getenv("SHERPA_ONNX_MIC_SAMPLE_RATE");
   if (pSampleRateStr) {
@@ -124,24 +101,9 @@ for a list of pre-trained models to download.
     mic_sample_rate = atof(pSampleRateStr);
   }
 
-  PaStream *stream;
-  PaError err =
-      Pa_OpenStream(&stream, &param, nullptr, /* &outputParameters, */
-                    mic_sample_rate,
-                    0,          // frames per buffer
-                    paClipOff,  // we won't output out of range samples
-                                // so don't bother clipping them
-                    RecordCallback, s.get());
-  if (err != paNoError) {
-    fprintf(stderr, "portaudio error: %s\n", Pa_GetErrorText(err));
-    exit(EXIT_FAILURE);
-  }
-
-  err = Pa_StartStream(stream);
-  fprintf(stderr, "Started\n");
-
-  if (err != paNoError) {
-    fprintf(stderr, "portaudio error: %s\n", Pa_GetErrorText(err));
+  if(!mic.OpenDevice(device_index, mic_sample_rate, 1,
+                RecordCallback, s.get())) {
+    fprintf(stderr, "portaudio error: %d\n", device_index);
     exit(EXIT_FAILURE);
   }
 
@@ -164,11 +126,5 @@ for a list of pre-trained models to download.
     Pa_Sleep(20);  // sleep for 20ms
   }
 
-  err = Pa_CloseStream(stream);
-  if (err != paNoError) {
-    fprintf(stderr, "portaudio error: %s\n", Pa_GetErrorText(err));
-    exit(EXIT_FAILURE);
-  }
-
   return 0;
 }
diff --git a/sherpa-onnx/csrc/sherpa-onnx-microphone-offline-audio-tagging.cc b/sherpa-onnx/csrc/sherpa-onnx-microphone-offline-audio-tagging.cc
index 0d568ec3..3dc1153b 100644
--- a/sherpa-onnx/csrc/sherpa-onnx-microphone-offline-audio-tagging.cc
+++ b/sherpa-onnx/csrc/sherpa-onnx-microphone-offline-audio-tagging.cc
@@ -120,11 +120,7 @@ for more models.
 
   sherpa_onnx::Microphone mic;
 
-  PaDeviceIndex num_devices = Pa_GetDeviceCount();
-  fprintf(stderr, "Num devices: %d\n", num_devices);
-
   int32_t device_index = Pa_GetDefaultInputDevice();
-
   if (device_index == paNoDevice) {
     fprintf(stderr, "No default input device found\n");
     fprintf(stderr, "If you are using Linux, please switch to \n");
@@ -138,26 +134,7 @@ for more models.
     device_index = atoi(pDeviceIndex);
   }
 
-  for (int32_t i = 0; i != num_devices; ++i) {
-    const PaDeviceInfo *info = Pa_GetDeviceInfo(i);
-    fprintf(stderr, " %s %d %s\n", (i == device_index) ? "*" : " ", i,
-            info->name);
-  }
-
-  PaStreamParameters param;
-  param.device = device_index;
-
-  fprintf(stderr, "Use device: %d\n", param.device);
-
-  const PaDeviceInfo *info = Pa_GetDeviceInfo(param.device);
-  fprintf(stderr, "  Name: %s\n", info->name);
-  fprintf(stderr, "  Max input channels: %d\n", info->maxInputChannels);
-
-  param.channelCount = 1;
-  param.sampleFormat = paFloat32;
-
-  param.suggestedLatency = info->defaultLowInputLatency;
-  param.hostApiSpecificStreamInfo = nullptr;
+  mic.PrintDevices(device_index);
   float mic_sample_rate = 16000;
   const char *pSampleRateStr = std::getenv("SHERPA_ONNX_MIC_SAMPLE_RATE");
   if (pSampleRateStr) {
@@ -165,24 +142,9 @@ for more models.
     mic_sample_rate = atof(pSampleRateStr);
   }
 
-  PaStream *stream;
-  PaError err =
-      Pa_OpenStream(&stream, &param, nullptr, /* &outputParameters, */
-                    mic_sample_rate,
-                    0,          // frames per buffer
-                    paClipOff,  // we won't output out of range samples
-                                // so don't bother clipping them
-                    RecordCallback, nullptr);
-  if (err != paNoError) {
-    fprintf(stderr, "portaudio error: %s\n", Pa_GetErrorText(err));
-    exit(EXIT_FAILURE);
-  }
-
-  err = Pa_StartStream(stream);
-  fprintf(stderr, "Started\n");
-
-  if (err != paNoError) {
-    fprintf(stderr, "portaudio error: %s\n", Pa_GetErrorText(err));
+  if (!mic.OpenDevice(device_index, mic_sample_rate, 1,
+                 RecordCallback, nullptr /* user_data */)){
+    fprintf(stderr, "portaudio error: %d\n", device_index);
     exit(EXIT_FAILURE);
   }
 
@@ -226,11 +188,5 @@ for more models.
   }
   t.join();
 
-  err = Pa_CloseStream(stream);
-  if (err != paNoError) {
-    fprintf(stderr, "portaudio error: %s\n", Pa_GetErrorText(err));
-    exit(EXIT_FAILURE);
-  }
-
   return 0;
 }
diff --git a/sherpa-onnx/csrc/sherpa-onnx-microphone-offline-speaker-identification.cc b/sherpa-onnx/csrc/sherpa-onnx-microphone-offline-speaker-identification.cc
index d3518c09..0d5c6322 100644
--- a/sherpa-onnx/csrc/sherpa-onnx-microphone-offline-speaker-identification.cc
+++ b/sherpa-onnx/csrc/sherpa-onnx-microphone-offline-speaker-identification.cc
@@ -220,9 +220,6 @@ Note that `zh` means Chinese, while `en` means English.
 
   sherpa_onnx::Microphone mic;
 
-  PaDeviceIndex num_devices = Pa_GetDeviceCount();
-  fprintf(stderr, "Num devices: %d\n", num_devices);
-
   int32_t device_index = Pa_GetDefaultInputDevice();
   if (device_index == paNoDevice) {
     fprintf(stderr, "No default input device found\n");
@@ -238,52 +235,18 @@ Note that `zh` means Chinese, while `en` means English.
     device_index = atoi(pDeviceIndex);
   }
 
-  for (int32_t i = 0; i != num_devices; ++i) {
-    const PaDeviceInfo *info = Pa_GetDeviceInfo(i);
-    fprintf(stderr, " %s %d %s\n", (i == device_index) ? "*" : " ", i,
-            info->name);
-  }
+  mic.PrintDevices(device_index);
 
-  PaStreamParameters param;
-  param.device = device_index;
-
-  fprintf(stderr, "Use device: %d\n", param.device);
-
-  const PaDeviceInfo *info = Pa_GetDeviceInfo(param.device);
-  fprintf(stderr, "  Name: %s\n", info->name);
-  fprintf(stderr, "  Max input channels: %d\n", info->maxInputChannels);
-
-  param.channelCount = 1;
-  param.sampleFormat = paFloat32;
-
-  param.suggestedLatency = info->defaultLowInputLatency;
-  param.hostApiSpecificStreamInfo = nullptr;
   float mic_sample_rate = 16000;
   const char *pSampleRateStr = std::getenv("SHERPA_ONNX_MIC_SAMPLE_RATE");
   if (pSampleRateStr) {
     fprintf(stderr, "Use sample rate %f for mic\n", mic_sample_rate);
     mic_sample_rate = atof(pSampleRateStr);
   }
-  float sample_rate = 16000;
 
-  PaStream *stream;
-  PaError err =
-      Pa_OpenStream(&stream, &param, nullptr, /* &outputParameters, */
-                    mic_sample_rate,
-                    0,          // frames per buffer
-                    paClipOff,  // we won't output out of range samples
-                                // so don't bother clipping them
-                    RecordCallback, nullptr);
-  if (err != paNoError) {
-    fprintf(stderr, "portaudio error: %s\n", Pa_GetErrorText(err));
-    exit(EXIT_FAILURE);
-  }
-
-  err = Pa_StartStream(stream);
-  fprintf(stderr, "Started\n");
-
-  if (err != paNoError) {
-    fprintf(stderr, "portaudio error: %s\n", Pa_GetErrorText(err));
+  if (!mic.OpenDevice(device_index, mic_sample_rate, 1,
+                 RecordCallback, nullptr /* user_data */)){
+    fprintf(stderr, "portaudio error: %d\n", device_index);
     exit(EXIT_FAILURE);
   }
 
@@ -323,11 +286,5 @@ Note that `zh` means Chinese, while `en` means English.
   }
   t.join();
 
-  err = Pa_CloseStream(stream);
-  if (err != paNoError) {
-    fprintf(stderr, "portaudio error: %s\n", Pa_GetErrorText(err));
-    exit(EXIT_FAILURE);
-  }
-
   return 0;
 }
diff --git a/sherpa-onnx/csrc/sherpa-onnx-microphone-offline.cc b/sherpa-onnx/csrc/sherpa-onnx-microphone-offline.cc
index a9875545..4d00b9ba 100644
--- a/sherpa-onnx/csrc/sherpa-onnx-microphone-offline.cc
+++ b/sherpa-onnx/csrc/sherpa-onnx-microphone-offline.cc
@@ -136,11 +136,7 @@ for a list of pre-trained models to download.
 
   sherpa_onnx::Microphone mic;
 
-  PaDeviceIndex num_devices = Pa_GetDeviceCount();
-  fprintf(stderr, "Num devices: %d\n", num_devices);
-
   int32_t device_index = Pa_GetDefaultInputDevice();
-
   if (device_index == paNoDevice) {
     fprintf(stderr, "No default input device found\n");
     fprintf(stderr, "If you are using Linux, please switch to \n");
@@ -154,26 +150,8 @@ for a list of pre-trained models to download.
     device_index = atoi(pDeviceIndex);
   }
 
-  for (int32_t i = 0; i != num_devices; ++i) {
-    const PaDeviceInfo *info = Pa_GetDeviceInfo(i);
-    fprintf(stderr, " %s %d %s\n", (i == device_index) ? "*" : " ", i,
-            info->name);
-  }
+  mic.PrintDevices(device_index);
 
-  PaStreamParameters param;
-  param.device = device_index;
-
-  fprintf(stderr, "Use device: %d\n", param.device);
-
-  const PaDeviceInfo *info = Pa_GetDeviceInfo(param.device);
-  fprintf(stderr, "  Name: %s\n", info->name);
-  fprintf(stderr, "  Max input channels: %d\n", info->maxInputChannels);
-
-  param.channelCount = 1;
-  param.sampleFormat = paFloat32;
-
-  param.suggestedLatency = info->defaultLowInputLatency;
-  param.hostApiSpecificStreamInfo = nullptr;
   float mic_sample_rate = 16000;
   const char *pSampleRateStr = std::getenv("SHERPA_ONNX_MIC_SAMPLE_RATE");
   if (pSampleRateStr) {
@@ -181,24 +159,9 @@ for a list of pre-trained models to download.
     mic_sample_rate = atof(pSampleRateStr);
   }
 
-  PaStream *stream;
-  PaError err =
-      Pa_OpenStream(&stream, &param, nullptr, /* &outputParameters, */
-                    mic_sample_rate,
-                    0,          // frames per buffer
-                    paClipOff,  // we won't output out of range samples
-                                // so don't bother clipping them
-                    RecordCallback, nullptr);
-  if (err != paNoError) {
-    fprintf(stderr, "portaudio error: %s\n", Pa_GetErrorText(err));
-    exit(EXIT_FAILURE);
-  }
-
-  err = Pa_StartStream(stream);
-  fprintf(stderr, "Started\n");
-
-  if (err != paNoError) {
-    fprintf(stderr, "portaudio error: %s\n", Pa_GetErrorText(err));
+  if (!mic.OpenDevice(device_index, mic_sample_rate, 1,
+                 RecordCallback, nullptr /* user_data */)){
+    fprintf(stderr, "portaudio error: %d\n", device_index);
     exit(EXIT_FAILURE);
   }
 
@@ -232,11 +195,5 @@ for a list of pre-trained models to download.
   }
   t.join();
 
-  err = Pa_CloseStream(stream);
-  if (err != paNoError) {
-    fprintf(stderr, "portaudio error: %s\n", Pa_GetErrorText(err));
-    exit(EXIT_FAILURE);
-  }
-
   return 0;
 }
diff --git a/sherpa-onnx/csrc/sherpa-onnx-microphone.cc b/sherpa-onnx/csrc/sherpa-onnx-microphone.cc
index f9f8ab32..c5b13bf7 100644
--- a/sherpa-onnx/csrc/sherpa-onnx-microphone.cc
+++ b/sherpa-onnx/csrc/sherpa-onnx-microphone.cc
@@ -106,11 +106,7 @@ for a list of pre-trained models to download.
 
   sherpa_onnx::Microphone mic;
 
-  PaDeviceIndex num_devices = Pa_GetDeviceCount();
-  fprintf(stderr, "Num devices: %d\n", num_devices);
-
   int32_t device_index = Pa_GetDefaultInputDevice();
-
   if (device_index == paNoDevice) {
     fprintf(stderr, "No default input device found\n");
     fprintf(stderr, "If you are using Linux, please switch to \n");
@@ -124,51 +120,18 @@ for a list of pre-trained models to download.
     device_index = atoi(pDeviceIndex);
   }
 
-  for (int32_t i = 0; i != num_devices; ++i) {
-    const PaDeviceInfo *info = Pa_GetDeviceInfo(i);
-    fprintf(stderr, " %s %d %s\n", (i == device_index) ? "*" : " ", i,
-            info->name);
-  }
+  mic.PrintDevices(device_index);
 
-  PaStreamParameters param;
-  param.device = device_index;
-
-  fprintf(stderr, "Use device: %d\n", param.device);
-
-  const PaDeviceInfo *info = Pa_GetDeviceInfo(param.device);
-  fprintf(stderr, "  Name: %s\n", info->name);
-  fprintf(stderr, "  Max input channels: %d\n", info->maxInputChannels);
-
-  param.channelCount = 1;
-  param.sampleFormat = paFloat32;
-
-  param.suggestedLatency = info->defaultLowInputLatency;
-  param.hostApiSpecificStreamInfo = nullptr;
+  float mic_sample_rate = 16000;
   const char *pSampleRateStr = std::getenv("SHERPA_ONNX_MIC_SAMPLE_RATE");
   if (pSampleRateStr) {
     fprintf(stderr, "Use sample rate %f for mic\n", mic_sample_rate);
     mic_sample_rate = atof(pSampleRateStr);
   }
-  float sample_rate = 16000;
 
-  PaStream *stream;
-  PaError err =
-      Pa_OpenStream(&stream, &param, nullptr, /* &outputParameters, */
-                    sample_rate,
-                    0,          // frames per buffer
-                    paClipOff,  // we won't output out of range samples
-                                // so don't bother clipping them
-                    RecordCallback, s.get());
-  if (err != paNoError) {
-    fprintf(stderr, "portaudio error: %s\n", Pa_GetErrorText(err));
-    exit(EXIT_FAILURE);
-  }
-
-  err = Pa_StartStream(stream);
-  fprintf(stderr, "Started\n");
-
-  if (err != paNoError) {
-    fprintf(stderr, "portaudio error: %s\n", Pa_GetErrorText(err));
+  if (!mic.OpenDevice(device_index, mic_sample_rate, 1,
+                 RecordCallback, nullptr /* user_data */)){
+    fprintf(stderr, "portaudio error: %d\n", device_index);
     exit(EXIT_FAILURE);
   }
 
@@ -213,11 +176,5 @@ for a list of pre-trained models to download.
     Pa_Sleep(20);  // sleep for 20ms
   }
 
-  err = Pa_CloseStream(stream);
-  if (err != paNoError) {
-    fprintf(stderr, "portaudio error: %s\n", Pa_GetErrorText(err));
-    exit(EXIT_FAILURE);
-  }
-
   return 0;
 }
diff --git a/sherpa-onnx/csrc/sherpa-onnx-vad-microphone-offline-asr.cc b/sherpa-onnx/csrc/sherpa-onnx-vad-microphone-offline-asr.cc
index d5cd920d..2ae17cbc 100644
--- a/sherpa-onnx/csrc/sherpa-onnx-vad-microphone-offline-asr.cc
+++ b/sherpa-onnx/csrc/sherpa-onnx-vad-microphone-offline-asr.cc
@@ -113,17 +113,7 @@ to download models for offline ASR.
 
   sherpa_onnx::Microphone mic;
 
-  PaDeviceIndex num_devices = Pa_GetDeviceCount();
-  fprintf(stderr, "Num devices: %d\n", num_devices);
-  if (num_devices == 0) {
-    fprintf(stderr,
-            "  If you are using Linux, please try "
-            "./build/bin/sherpa-onnx-vad-alsa-offline-asr\n");
-    exit(-1);
-  }
-
   int32_t device_index = Pa_GetDefaultInputDevice();
-
   if (device_index == paNoDevice) {
     fprintf(stderr, "No default input device found\n");
     fprintf(stderr,
@@ -137,33 +127,20 @@ to download models for offline ASR.
     fprintf(stderr, "Use specified device: %s\n", pDeviceIndex);
     device_index = atoi(pDeviceIndex);
   }
+  mic.PrintDevices(device_index);
 
-  for (int32_t i = 0; i != num_devices; ++i) {
-    const PaDeviceInfo *info = Pa_GetDeviceInfo(i);
-    fprintf(stderr, " %s %d %s\n", (i == device_index) ? "*" : " ", i,
-            info->name);
-  }
-
-  PaStreamParameters param;
-  param.device = device_index;
-
-  fprintf(stderr, "Use device: %d\n", param.device);
-
-  const PaDeviceInfo *info = Pa_GetDeviceInfo(param.device);
-  fprintf(stderr, "  Name: %s\n", info->name);
-  fprintf(stderr, "  Max input channels: %d\n", info->maxInputChannels);
-
-  param.channelCount = 1;
-  param.sampleFormat = paFloat32;
-
-  param.suggestedLatency = info->defaultLowInputLatency;
-  param.hostApiSpecificStreamInfo = nullptr;
   float mic_sample_rate = 16000;
   const char *pSampleRateStr = std::getenv("SHERPA_ONNX_MIC_SAMPLE_RATE");
   if (pSampleRateStr) {
     fprintf(stderr, "Use sample rate %f for mic\n", mic_sample_rate);
     mic_sample_rate = atof(pSampleRateStr);
   }
+
+  if (!mic.OpenDevice(device_index, mic_sample_rate, 1, RecordCallback, nullptr)) {
+    fprintf(stderr, "Failed to open device %d\n", device_index);
+    exit(EXIT_FAILURE);
+  }
+
   float sample_rate = 16000;
   std::unique_ptr<sherpa_onnx::LinearResample> resampler;
   if (mic_sample_rate != sample_rate) {
@@ -175,25 +152,6 @@ to download models for offline ASR.
         mic_sample_rate, sample_rate, lowpass_cutoff, lowpass_filter_width);
   }
 
-  PaStream *stream;
-  PaError err =
-      Pa_OpenStream(&stream, &param, nullptr, /* &outputParameters, */
-                    mic_sample_rate,
-                    0,          // frames per buffer
-                    paClipOff,  // we won't output out of range samples
-                                // so don't bother clipping them
-                    RecordCallback, nullptr);
-  if (err != paNoError) {
-    fprintf(stderr, "portaudio error: %s\n", Pa_GetErrorText(err));
-    exit(EXIT_FAILURE);
-  }
-
-  err = Pa_StartStream(stream);
-  if (err != paNoError) {
-    fprintf(stderr, "portaudio error: %s\n", Pa_GetErrorText(err));
-    exit(EXIT_FAILURE);
-  }
-
   auto vad = std::make_unique<sherpa_onnx::VoiceActivityDetector>(vad_config);
 
   fprintf(stderr, "Started. Please speak\n");
@@ -236,11 +194,5 @@ to download models for offline ASR.
     Pa_Sleep(100);  // sleep for 100ms
   }
 
-  err = Pa_CloseStream(stream);
-  if (err != paNoError) {
-    fprintf(stderr, "portaudio error: %s\n", Pa_GetErrorText(err));
-    exit(EXIT_FAILURE);
-  }
-
   return 0;
 }
diff --git a/sherpa-onnx/csrc/sherpa-onnx-vad-microphone.cc b/sherpa-onnx/csrc/sherpa-onnx-vad-microphone.cc
index 103cf7c6..e6360063 100644
--- a/sherpa-onnx/csrc/sherpa-onnx-vad-microphone.cc
+++ b/sherpa-onnx/csrc/sherpa-onnx-vad-microphone.cc
@@ -74,11 +74,8 @@ wget https://github.com/snakers4/silero-vad/raw/master/src/silero_vad/data/siler
 
   sherpa_onnx::Microphone mic;
 
-  PaDeviceIndex num_devices = Pa_GetDeviceCount();
-  fprintf(stderr, "Num devices: %d\n", num_devices);
 
   int32_t device_index = Pa_GetDefaultInputDevice();
-
   if (device_index == paNoDevice) {
     fprintf(stderr, "No default input device found\n");
     fprintf(stderr, "If you are using Linux, please switch to \n");
@@ -91,35 +88,20 @@ wget https://github.com/snakers4/silero-vad/raw/master/src/silero_vad/data/siler
     fprintf(stderr, "Use specified device: %s\n", pDeviceIndex);
     device_index = atoi(pDeviceIndex);
   }
+  mic.PrintDevices(device_index);
 
-  for (int32_t i = 0; i != num_devices; ++i) {
-    const PaDeviceInfo *info = Pa_GetDeviceInfo(i);
-    fprintf(stderr, " %s %d %s\n", (i == device_index) ? "*" : " ", i,
-            info->name);
-  }
-
-  PaStreamParameters param;
-  param.device = device_index;
-
-  fprintf(stderr, "Use device: %d\n", param.device);
-
-  const PaDeviceInfo *info = Pa_GetDeviceInfo(param.device);
-  fprintf(stderr, "  Name: %s\n", info->name);
-  fprintf(stderr, "  Max input channels: %d\n", info->maxInputChannels);
-
-  param.channelCount = 1;
-  param.sampleFormat = paFloat32;
-
-  param.suggestedLatency = info->defaultLowInputLatency;
-  param.hostApiSpecificStreamInfo = nullptr;
   float mic_sample_rate = 16000;
   const char *pSampleRateStr = std::getenv("SHERPA_ONNX_MIC_SAMPLE_RATE");
   if (pSampleRateStr) {
     fprintf(stderr, "Use sample rate %f for mic\n", mic_sample_rate);
     mic_sample_rate = atof(pSampleRateStr);
   }
-  float sample_rate = 16000;
+  if (!mic.OpenDevice(device_index, mic_sample_rate, 1, RecordCallback, nullptr)) {
+    fprintf(stderr, "Failed to open microphone device %d\n", device_index);
+    exit(EXIT_FAILURE);
+  }
 
+  float sample_rate = 16000;
   std::unique_ptr<sherpa_onnx::LinearResample> resampler;
   if (mic_sample_rate != sample_rate) {
     float min_freq = std::min(mic_sample_rate, sample_rate);
@@ -130,30 +112,8 @@ wget https://github.com/snakers4/silero-vad/raw/master/src/silero_vad/data/siler
         mic_sample_rate, sample_rate, lowpass_cutoff, lowpass_filter_width);
   }
 
-  PaStream *stream;
-  PaError err =
-      Pa_OpenStream(&stream, &param, nullptr, /* &outputParameters, */
-                    mic_sample_rate,
-                    0,          // frames per buffer
-                    paClipOff,  // we won't output out of range samples
-                                // so don't bother clipping them
-                    RecordCallback, nullptr);
-  if (err != paNoError) {
-    fprintf(stderr, "portaudio error: %s\n", Pa_GetErrorText(err));
-    exit(EXIT_FAILURE);
-  }
-
-  err = Pa_StartStream(stream);
-
   auto vad = std::make_unique<sherpa_onnx::VoiceActivityDetector>(config);
 
-  fprintf(stderr, "Started\n");
-
-  if (err != paNoError) {
-    fprintf(stderr, "portaudio error: %s\n", Pa_GetErrorText(err));
-    exit(EXIT_FAILURE);
-  }
-
   int32_t window_size = config.silero_vad.window_size;
   bool printed = false;
 
@@ -202,11 +162,5 @@ wget https://github.com/snakers4/silero-vad/raw/master/src/silero_vad/data/siler
     Pa_Sleep(100);  // sleep for 100ms
   }
 
-  err = Pa_CloseStream(stream);
-  if (err != paNoError) {
-    fprintf(stderr, "portaudio error: %s\n", Pa_GetErrorText(err));
-    exit(EXIT_FAILURE);
-  }
-
   return 0;
 }