Fix keyword spotting. (#1689)

Reset the stream right after detecting a keyword

cxx-api-examples/CMakeLists.txt

@@ -3,6 +3,9 @@ include_directories(${CMAKE_SOURCE_DIR})
 add_executable(streaming-zipformer-cxx-api ./streaming-zipformer-cxx-api.cc)
 target_link_libraries(streaming-zipformer-cxx-api sherpa-onnx-cxx-api)
 
+add_executable(kws-cxx-api ./kws-cxx-api.cc)
+target_link_libraries(kws-cxx-api sherpa-onnx-cxx-api)
+
 add_executable(streaming-zipformer-rtf-cxx-api ./streaming-zipformer-rtf-cxx-api.cc)
 target_link_libraries(streaming-zipformer-rtf-cxx-api sherpa-onnx-cxx-api)
 

cxx-api-examples/kws-cxx-api.cc

@@ -0,0 +1,141 @@
+// cxx-api-examples/kws-cxx-api.cc
+//
+// Copyright (c)  2025  Xiaomi Corporation
+//
+// This file demonstrates how to use keywords spotter with sherpa-onnx's C
+// clang-format off
+//
+// Usage
+//
+// wget https://github.com/k2-fsa/sherpa-onnx/releases/download/kws-models/sherpa-onnx-kws-zipformer-wenetspeech-3.3M-2024-01-01-mobile.tar.bz2
+// tar xvf sherpa-onnx-kws-zipformer-wenetspeech-3.3M-2024-01-01-mobile.tar.bz2
+// rm sherpa-onnx-kws-zipformer-wenetspeech-3.3M-2024-01-01-mobile.tar.bz2
+//
+// ./kws-cxx-api
+//
+// clang-format on
+#include <array>
+#include <iostream>
+
+#include "sherpa-onnx/c-api/cxx-api.h"
+
+int32_t main() {
+  using namespace sherpa_onnx::cxx;  // NOLINT
+
+  KeywordSpotterConfig config;
+  config.model_config.transducer.encoder =
+      "./sherpa-onnx-kws-zipformer-wenetspeech-3.3M-2024-01-01/"
+      "encoder-epoch-12-avg-2-chunk-16-left-64.onnx";
+
+  config.model_config.transducer.decoder =
+      "./sherpa-onnx-kws-zipformer-wenetspeech-3.3M-2024-01-01/"
+      "decoder-epoch-12-avg-2-chunk-16-left-64.onnx";
+
+  config.model_config.transducer.joiner =
+      "./sherpa-onnx-kws-zipformer-wenetspeech-3.3M-2024-01-01/"
+      "joiner-epoch-12-avg-2-chunk-16-left-64.onnx";
+
+  config.model_config.tokens =
+      "./sherpa-onnx-kws-zipformer-wenetspeech-3.3M-2024-01-01/tokens.txt";
+
+  config.model_config.provider = "cpu";
+  config.model_config.num_threads = 1;
+  config.model_config.debug = 1;
+
+  config.keywords_file =
+      "./sherpa-onnx-kws-zipformer-wenetspeech-3.3M-2024-01-01/test_wavs/"
+      "test_keywords.txt";
+
+  KeywordSpotter kws = KeywordSpotter::Create(config);
+  if (!kws.Get()) {
+    std::cerr << "Please check your config\n";
+    return -1;
+  }
+
+  std::cout
+      << "--Test pre-defined keywords from test_wavs/test_keywords.txt--\n";
+
+  std::string wave_filename =
+      "./sherpa-onnx-kws-zipformer-wenetspeech-3.3M-2024-01-01/test_wavs/3.wav";
+
+  std::array<float, 8000> tail_paddings = {0};  // 0.5 seconds
+
+  Wave wave = ReadWave(wave_filename);
+  if (wave.samples.empty()) {
+    std::cerr << "Failed to read: '" << wave_filename << "'\n";
+    return -1;
+  }
+
+  OnlineStream stream = kws.CreateStream();
+  if (!stream.Get()) {
+    std::cerr << "Failed to create stream\n";
+    return -1;
+  }
+
+  stream.AcceptWaveform(wave.sample_rate, wave.samples.data(),
+                        wave.samples.size());
+
+  stream.AcceptWaveform(wave.sample_rate, tail_paddings.data(),
+                        tail_paddings.size());
+  stream.InputFinished();
+
+  while (kws.IsReady(&stream)) {
+    kws.Decode(&stream);
+    auto r = kws.GetResult(&stream);
+    if (!r.keyword.empty()) {
+      std::cout << "Detected keyword: " << r.json << "\n";
+
+      // Remember to reset the keyword stream right after a keyword is detected
+      kws.Reset(&stream);
+    }
+  }
+
+  // --------------------------------------------------------------------------
+
+  std::cout << "--Use pre-defined keywords + add a new keyword--\n";
+
+  stream = kws.CreateStream("y ǎn y uán @演员");
+
+  stream.AcceptWaveform(wave.sample_rate, wave.samples.data(),
+                        wave.samples.size());
+
+  stream.AcceptWaveform(wave.sample_rate, tail_paddings.data(),
+                        tail_paddings.size());
+  stream.InputFinished();
+
+  while (kws.IsReady(&stream)) {
+    kws.Decode(&stream);
+    auto r = kws.GetResult(&stream);
+    if (!r.keyword.empty()) {
+      std::cout << "Detected keyword: " << r.json << "\n";
+
+      // Remember to reset the keyword stream right after a keyword is detected
+      kws.Reset(&stream);
+    }
+  }
+
+  // --------------------------------------------------------------------------
+
+  std::cout << "--Use pre-defined keywords + add two new keywords--\n";
+
+  stream = kws.CreateStream("y ǎn y uán @演员/zh ī m íng @知名");
+
+  stream.AcceptWaveform(wave.sample_rate, wave.samples.data(),
+                        wave.samples.size());
+
+  stream.AcceptWaveform(wave.sample_rate, tail_paddings.data(),
+                        tail_paddings.size());
+  stream.InputFinished();
+
+  while (kws.IsReady(&stream)) {
+    kws.Decode(&stream);
+    auto r = kws.GetResult(&stream);
+    if (!r.keyword.empty()) {
+      std::cout << "Detected keyword: " << r.json << "\n";
+
+      // Remember to reset the keyword stream right after a keyword is detected
+      kws.Reset(&stream);
+    }
+  }
+  return 0;
+}