Support using alsa to access the microphone with non-streaming ASR models (#517)

@@ -166,6 +166,7 @@ class BuildExtension(build_ext):
 
         if enable_alsa():
             binaries += ["sherpa-onnx-alsa"]
+            binaries += ["sherpa-onnx-alsa-offline"]
             binaries += ["sherpa-onnx-offline-tts-play-alsa"]
             binaries += ["sherpa-onnx-alsa-offline-speaker-identification"]
 

@@ -59,6 +59,7 @@ def get_binaries_to_install():
 
     if enable_alsa():
         binaries += ["sherpa-onnx-alsa"]
+        binaries += ["sherpa-onnx-alsa-offline"]
         binaries += ["sherpa-onnx-offline-tts-play-alsa"]
         binaries += ["sherpa-onnx-alsa-offline-speaker-identification"]
 

@@ -231,10 +231,12 @@ endif()
 if(SHERPA_ONNX_HAS_ALSA AND SHERPA_ONNX_ENABLE_BINARY)
   add_executable(sherpa-onnx-alsa sherpa-onnx-alsa.cc alsa.cc)
   add_executable(sherpa-onnx-offline-tts-play-alsa sherpa-onnx-offline-tts-play-alsa.cc alsa-play.cc)
+  add_executable(sherpa-onnx-alsa-offline sherpa-onnx-alsa-offline.cc alsa.cc)
   add_executable(sherpa-onnx-alsa-offline-speaker-identification sherpa-onnx-alsa-offline-speaker-identification.cc alsa.cc)
 
   set(exes
     sherpa-onnx-alsa
+    sherpa-onnx-alsa-offline
     sherpa-onnx-offline-tts-play-alsa
     sherpa-onnx-alsa-offline-speaker-identification
   )

+// sherpa-onnx/csrc/sherpa-onnx-alsa-offline.cc
+//
+// Copyright (c)  2022-2024  Xiaomi Corporation
+
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <algorithm>
+#include <cctype>  // std::tolower
+#include <chrono>  // NOLINT
+#include <mutex>   // NOLINT
+#include <thread>  // NOLINT
+
+#include "sherpa-onnx/csrc/alsa.h"
+#include "sherpa-onnx/csrc/macros.h"
+#include "sherpa-onnx/csrc/offline-recognizer.h"
+
+enum class State {
+  kIdle,
+  kRecording,
+  kDecoding,
+};
+
+State state = State::kIdle;
+
+// true to stop the program and exit
+bool stop = false;
+
+std::vector<float> samples;
+std::mutex samples_mutex;
+
+static void DetectKeyPress() {
+  SHERPA_ONNX_LOGE("Press Enter to start");
+  int32_t key;
+  while (!stop && (key = getchar())) {
+    if (key != 0x0a) {
+      continue;
+    }
+
+    switch (state) {
+      case State::kIdle:
+        SHERPA_ONNX_LOGE("Start recording. Press Enter to stop recording");
+        state = State::kRecording;
+        {
+          std::lock_guard<std::mutex> lock(samples_mutex);
+          samples.clear();
+        }
+        break;
+      case State::kRecording:
+        SHERPA_ONNX_LOGE("Stop recording. Decoding ...");
+        state = State::kDecoding;
+        break;
+      case State::kDecoding:
+        break;
+    }
+  }
+}
+
+static void Record(const char *device_name, int32_t expected_sample_rate) {
+  sherpa_onnx::Alsa alsa(device_name);
+
+  if (alsa.GetExpectedSampleRate() != expected_sample_rate) {
+    fprintf(stderr, "sample rate: %d != %d\n", alsa.GetExpectedSampleRate(),
+            expected_sample_rate);
+    exit(-1);
+  }
+
+  int32_t chunk = 0.1 * alsa.GetActualSampleRate();
+  while (!stop) {
+    std::lock_guard<std::mutex> lock(samples_mutex);
+    const std::vector<float> &s = alsa.Read(chunk);
+    samples.insert(samples.end(), s.begin(), s.end());
+  }
+}
+
+static void Handler(int32_t sig) {
+  stop = true;
+  fprintf(stderr, "\nCaught Ctrl + C. Press Enter to exit\n");
+}
+
+int32_t main(int32_t argc, char *argv[]) {
+  signal(SIGINT, Handler);
+
+  const char *kUsageMessage = R"usage(
+This program uses non-streaming models with microphone for speech recognition.
+Usage:
+
+(1) Transducer from icefall
+
+  ./bin/sherpa-onnx-alsa-offline \
+    --tokens=/path/to/tokens.txt \
+    --encoder=/path/to/encoder.onnx \
+    --decoder=/path/to/decoder.onnx \
+    --joiner=/path/to/joiner.onnx \
+    --num-threads=2 \
+    --decoding-method=greedy_search \
+    device_name
+
+(2) Paraformer from FunASR
+
+  ./bin/sherpa-onnx-alsa-offline \
+    --tokens=/path/to/tokens.txt \
+    --paraformer=/path/to/model.onnx \
+    --num-threads=1 \
+    device_name
+
+(3) Whisper models
+
+  ./bin/sherpa-onnx-alsa-offline \
+    --whisper-encoder=./sherpa-onnx-whisper-base.en/base.en-encoder.int8.onnx \
+    --whisper-decoder=./sherpa-onnx-whisper-base.en/base.en-decoder.int8.onnx \
+    --tokens=./sherpa-onnx-whisper-base.en/base.en-tokens.txt \
+    --num-threads=1 \
+    device_name
+
+Please refer to
+https://k2-fsa.github.io/sherpa/onnx/pretrained_models/index.html
+for a list of pre-trained models to download.
+
+The device name specifies which microphone to use in case there are several
+on you system. You can use
+
+  arecord -l
+
+to find all available microphones on your computer. For instance, if it outputs
+
+**** List of CAPTURE Hardware Devices ****
+card 3: UACDemoV10 [UACDemoV1.0], device 0: USB Audio [USB Audio]
+  Subdevices: 1/1
+  Subdevice #0: subdevice #0
+
+and if you want to select card 3 and the device 0 on that card, please use:
+
+  plughw:3,0
+
+as the device_name.
+)usage";
+
+  sherpa_onnx::ParseOptions po(kUsageMessage);
+  sherpa_onnx::OfflineRecognizerConfig config;
+  config.Register(&po);
+
+  po.Read(argc, argv);
+  if (po.NumArgs() != 1) {
+    fprintf(stderr, "Please provide only 1 argument: the device name\n");
+    po.PrintUsage();
+    exit(EXIT_FAILURE);
+  }
+
+  fprintf(stderr, "%s\n", config.ToString().c_str());
+
+  if (!config.Validate()) {
+    fprintf(stderr, "Errors in config!\n");
+    return -1;
+  }
+
+  SHERPA_ONNX_LOGE("Creating recognizer ...");
+  sherpa_onnx::OfflineRecognizer recognizer(config);
+  SHERPA_ONNX_LOGE("Recognizer created!");
+
+  std::string device_name = po.GetArg(1);
+  fprintf(stderr, "Use recording device: %s\n", device_name.c_str());
+
+  int32_t sample_rate = config.feat_config.sampling_rate;
+
+  std::thread t(DetectKeyPress);
+  std::thread t2(Record, device_name.c_str(), sample_rate);
+
+  while (!stop) {
+    switch (state) {
+      case State::kIdle:
+        break;
+      case State::kRecording:
+        break;
+      case State::kDecoding: {
+        std::vector<float> buf;
+        {
+          std::lock_guard<std::mutex> lock(samples_mutex);
+          buf = std::move(samples);
+        }
+
+        auto s = recognizer.CreateStream();
+        s->AcceptWaveform(sample_rate, buf.data(), buf.size());
+        recognizer.DecodeStream(s.get());
+        SHERPA_ONNX_LOGE("Decoding Done! Result is:");
+        SHERPA_ONNX_LOGE("%s", s->GetResult().text.c_str());
+
+        state = State::kIdle;
+        SHERPA_ONNX_LOGE("Press Enter to start");
+        break;
+      }
+    }
+
+    using namespace std::chrono_literals;
+    std::this_thread::sleep_for(20ms);  // sleep for 20ms
+  }
+  t.join();
+  t2.join();
+
+  return 0;
+}