Add streaming CTC ASR APIs for node-addon-api (#867)

.github/scripts/test-nodejs-addon-npm.sh

@@ -5,15 +5,6 @@ set -ex
 d=nodejs-addon-examples
 echo "dir: $d"
 cd $d
-npm install --verbose
-git status
-ls -lh
-ls -lh node_modules
-
-export DYLD_LIBRARY_PATH=$PWD/node_modules/sherpa-onnx-darwin-x64:$DYLD_LIBRARY_PATH
-export DYLD_LIBRARY_PATH=$PWD/node_modules/sherpa-onnx-darwin-arm64:$DYLD_LIBRARY_PATH
-export LD_LIBRARY_PATH=$PWD/node_modules/sherpa-onnx-linux-x64:$LD_LIBRARY_PATH
-export LD_LIBRARY_PATH=$PWD/node_modules/sherpa-onnx-linux-arm64:$LD_LIBRARY_PATH
 
 curl -SL -O https://github.com/k2-fsa/sherpa-onnx/releases/download/asr-models/sherpa-onnx-streaming-zipformer-bilingual-zh-en-2023-02-20.tar.bz2
 tar xvf sherpa-onnx-streaming-zipformer-bilingual-zh-en-2023-02-20.tar.bz2
@@ -22,3 +13,14 @@ rm sherpa-onnx-streaming-zipformer-bilingual-zh-en-2023-02-20.tar.bz2
 node test_asr_streaming_transducer.js
 
 rm -rf sherpa-onnx-streaming-zipformer-bilingual-zh-en-2023-02-20
+
+curl -SL -O https://github.com/k2-fsa/sherpa-onnx/releases/download/asr-models/sherpa-onnx-streaming-zipformer-ctc-small-2024-03-18.tar.bz2
+tar xvf sherpa-onnx-streaming-zipformer-ctc-small-2024-03-18.tar.bz2
+rm sherpa-onnx-streaming-zipformer-ctc-small-2024-03-18.tar.bz2
+
+node ./test_asr_streaming_ctc.js
+
+# To decode with HLG.fst
+node ./test_asr_streaming_ctc_hlg.js
+
+rm -rf sherpa-onnx-streaming-zipformer-ctc-small-2024-03-18

.github/workflows/test-nodejs-addon-api.yaml

@@ -152,17 +152,23 @@ jobs:
 
           ./node_modules/.bin/cmake-js compile --log-level verbose
 
-      - name: Test streaming transducer
+      - name: Run tests
         shell: bash
         run: |
           export PATH=$PWD/build/install/lib:$PATH
           export LD_LIBRARY_PATH=$PWD/build/install/lib:$LD_LIBRARY_PATH
+          d=nodejs-addon-examples
+          cd $d
+          files=$(ls *.js)
+          echo $files
+          for f in ${files[@]}; do
+            echo $f
+            sed -i.bak s%sherpa-onnx-node%./sherpa-onnx% ./$f
+          done
+          cd ..
 
-          cd scripts/node-addon-api
-          curl -SL -O https://github.com/k2-fsa/sherpa-onnx/releases/download/asr-models/sherpa-onnx-streaming-zipformer-bilingual-zh-en-2023-02-20.tar.bz2
-          tar xvf sherpa-onnx-streaming-zipformer-bilingual-zh-en-2023-02-20.tar.bz2
-          rm sherpa-onnx-streaming-zipformer-bilingual-zh-en-2023-02-20.tar.bz2
+          cp -v scripts/node-addon-api/build/Release/sherpa-onnx.node $d/
+          cp -v scripts/node-addon-api/lib/*.js $d/
+          cp -v ./build/install/lib/lib*  $d/
 
-          node test/test_asr_streaming_transducer.js
-
-          rm -rf sherpa-onnx-streaming-zipformer-bilingual-zh-en-2023-02-20
+          .github/scripts/test-nodejs-addon-npm.sh

.github/workflows/test-nodejs-addon-npm.yaml

@@ -63,4 +63,19 @@ jobs:
       - name: Run tests
         shell: bash
         run: |
+          d=nodejs-addon-examples
+          echo "dir: $d"
+          cd $d
+          npm install --verbose
+          git status
+          ls -lh
+          ls -lh node_modules
+
+          export DYLD_LIBRARY_PATH=$PWD/node_modules/sherpa-onnx-darwin-x64:$DYLD_LIBRARY_PATH
+          export DYLD_LIBRARY_PATH=$PWD/node_modules/sherpa-onnx-darwin-arm64:$DYLD_LIBRARY_PATH
+          export LD_LIBRARY_PATH=$PWD/node_modules/sherpa-onnx-linux-x64:$LD_LIBRARY_PATH
+          export LD_LIBRARY_PATH=$PWD/node_modules/sherpa-onnx-linux-arm64:$LD_LIBRARY_PATH
+
+          cd ../
+
           .github/scripts/test-nodejs-addon-npm.sh

nodejs-addon-examples/README.md

@@ -27,6 +27,18 @@ export LD_LIBRARY_PATH=$PWD/node_modules/sherpa-onnx-linux-x64:$LD_LIBRARY_PATH
 export LD_LIBRARY_PATH=$PWD/node_modules/sherpa-onnx-linux-arm64:$LD_LIBRARY_PATH
 ```
 
+# Voice Activity detection (VAD)
+
+```bash
+wget https://github.com/k2-fsa/sherpa-onnx/releases/download/asr-models/silero_vad.onnx
+
+
+# To run the test with a microphone, you need to install the package naudiodon2
+npm install naudiodon2
+
+node ./test_vad_microphone.js
+```
+
 ## Streaming speech recognition with zipformer transducer
 
 ```bash
@@ -36,21 +48,27 @@ rm sherpa-onnx-streaming-zipformer-bilingual-zh-en-2023-02-20.tar.bz2
 
 node ./test_asr_streaming_transducer.js
 
-# To run the test with microphone, you need to install the package naudiodon2
+# To run the test with a microphone, you need to install the package naudiodon2
 npm install naudiodon2
 
 node ./test_asr_streaming_transducer_microphone.js
 ```
 
-# VAD
+## Streaming speech recognition with zipformer CTC
 
 ```bash
-wget https://github.com/k2-fsa/sherpa-onnx/releases/download/asr-models/silero_vad.onnx
+wget https://github.com/k2-fsa/sherpa-onnx/releases/download/asr-models/sherpa-onnx-streaming-zipformer-ctc-small-2024-03-18.tar.bz2
+tar xvf sherpa-onnx-streaming-zipformer-ctc-small-2024-03-18.tar.bz2
+rm sherpa-onnx-streaming-zipformer-ctc-small-2024-03-18.tar.bz2
 
+node ./test_asr_streaming_ctc.js
 
-# To run the test with microphone, you need to install the package naudiodon2
+# To decode with HLG.fst
+node ./test_asr_streaming_ctc_hlg.js
+
+# To run the test with a microphone, you need to install the package naudiodon2
 npm install naudiodon2
 
-node ./test_vad_microphone.js
+node ./test_asr_streaming_ctc_microphone.js
+node ./test_asr_streaming_ctc_hlg_microphone.js
 ```
-

nodejs-addon-examples/test_asr_streaming_ctc.js

@@ -0,0 +1,55 @@
+// Copyright (c)  2024  Xiaomi Corporation
+const sherpa_onnx = require('sherpa-onnx-node');
+const performance = require('perf_hooks').performance;
+
+
+// Please download test files from
+// https://github.com/k2-fsa/sherpa-onnx/releases/tag/asr-models
+const config = {
+  'featConfig': {
+    'sampleRate': 16000,
+    'featureDim': 80,
+  },
+  'modelConfig': {
+    'zipformer2Ctc': {
+      'model':
+          './sherpa-onnx-streaming-zipformer-ctc-small-2024-03-18/ctc-epoch-30-avg-3-chunk-16-left-128.int8.onnx',
+    },
+    'tokens':
+        './sherpa-onnx-streaming-zipformer-ctc-small-2024-03-18/tokens.txt',
+    'numThreads': 2,
+    'provider': 'cpu',
+    'debug': 1,
+  }
+};
+
+const waveFilename =
+    './sherpa-onnx-streaming-zipformer-ctc-small-2024-03-18/test_wavs/0.wav';
+
+const recognizer = new sherpa_onnx.OnlineRecognizer(config);
+console.log('Started')
+let start = performance.now();
+const stream = recognizer.createStream();
+const wave = sherpa_onnx.readWave(waveFilename);
+stream.acceptWaveform({sampleRate: wave.sampleRate, samples: wave.samples});
+
+const tailPadding = new Float32Array(wave.sampleRate * 0.4);
+stream.acceptWaveform({samples: tailPadding, sampleRate: wave.sampleRate});
+
+while (recognizer.isReady(stream)) {
+  recognizer.decode(stream);
+}
+result = recognizer.getResult(stream)
+let stop = performance.now();
+console.log('Done')
+
+const elapsed_seconds = (stop - start) / 1000;
+const duration = wave.samples.length / wave.sampleRate;
+const real_time_factor = elapsed_seconds / duration;
+console.log('Wave duration', duration.toFixed(3), 'secodns')
+console.log('Elapsed', elapsed_seconds.toFixed(3), 'secodns')
+console.log(
+    `RTF = ${elapsed_seconds.toFixed(3)}/${duration.toFixed(3)} =`,
+    real_time_factor.toFixed(3))
+console.log(waveFilename)
+console.log('result\n', result)

nodejs-addon-examples/test_asr_streaming_ctc_hlg.js

@@ -0,0 +1,58 @@
+// Copyright (c)  2024  Xiaomi Corporation
+const sherpa_onnx = require('sherpa-onnx-node');
+const performance = require('perf_hooks').performance;
+
+
+// Please download test files from
+// https://github.com/k2-fsa/sherpa-onnx/releases/tag/asr-models
+const config = {
+  'featConfig': {
+    'sampleRate': 16000,
+    'featureDim': 80,
+  },
+  'modelConfig': {
+    'zipformer2Ctc': {
+      'model':
+          './sherpa-onnx-streaming-zipformer-ctc-small-2024-03-18/ctc-epoch-30-avg-3-chunk-16-left-128.int8.onnx',
+    },
+    'tokens':
+        './sherpa-onnx-streaming-zipformer-ctc-small-2024-03-18/tokens.txt',
+    'numThreads': 2,
+    'provider': 'cpu',
+    'debug': 1,
+  },
+  'ctcFstDecoderConfig': {
+    'graph': './sherpa-onnx-streaming-zipformer-ctc-small-2024-03-18/HLG.fst',
+  },
+};
+
+const waveFilename =
+    './sherpa-onnx-streaming-zipformer-ctc-small-2024-03-18/test_wavs/1.wav';
+
+const recognizer = new sherpa_onnx.OnlineRecognizer(config);
+console.log('Started')
+let start = performance.now();
+const stream = recognizer.createStream();
+const wave = sherpa_onnx.readWave(waveFilename);
+stream.acceptWaveform({sampleRate: wave.sampleRate, samples: wave.samples});
+
+const tailPadding = new Float32Array(wave.sampleRate * 0.4);
+stream.acceptWaveform({samples: tailPadding, sampleRate: wave.sampleRate});
+
+while (recognizer.isReady(stream)) {
+  recognizer.decode(stream);
+}
+result = recognizer.getResult(stream)
+let stop = performance.now();
+console.log('Done')
+
+const elapsed_seconds = (stop - start) / 1000;
+const duration = wave.samples.length / wave.sampleRate;
+const real_time_factor = elapsed_seconds / duration;
+console.log('Wave duration', duration.toFixed(3), 'secodns')
+console.log('Elapsed', elapsed_seconds.toFixed(3), 'secodns')
+console.log(
+    `RTF = ${elapsed_seconds.toFixed(3)}/${duration.toFixed(3)} =`,
+    real_time_factor.toFixed(3))
+console.log(waveFilename)
+console.log('result\n', result)

nodejs-addon-examples/test_asr_streaming_ctc_hlg_microphone.js

@@ -0,0 +1,89 @@
+// Copyright (c)  2023-2024  Xiaomi Corporation (authors: Fangjun Kuang)
+//
+const portAudio = require('naudiodon2');
+// console.log(portAudio.getDevices());
+
+const sherpa_onnx = require('sherpa-onnx-node');
+
+function createOnlineRecognizer() {
+  const config = {
+    'featConfig': {
+      'sampleRate': 16000,
+      'featureDim': 80,
+    },
+    'modelConfig': {
+      'zipformer2Ctc': {
+        'model':
+            './sherpa-onnx-streaming-zipformer-ctc-small-2024-03-18/ctc-epoch-30-avg-3-chunk-16-left-128.int8.onnx',
+      },
+      'tokens':
+          './sherpa-onnx-streaming-zipformer-ctc-small-2024-03-18/tokens.txt',
+      'numThreads': 2,
+      'provider': 'cpu',
+      'debug': 1,
+    },
+    'ctcFstDecoderConfig': {
+      'graph': './sherpa-onnx-streaming-zipformer-ctc-small-2024-03-18/HLG.fst',
+    },
+    'enableEndpoint': true,
+    'rule1MinTrailingSilence': 2.4,
+    'rule2MinTrailingSilence': 1.2,
+    'rule3MinUtteranceLength': 20
+  };
+
+  return new sherpa_onnx.OnlineRecognizer(config);
+}
+
+const recognizer = createOnlineRecognizer();
+const stream = recognizer.createStream();
+
+let lastText = '';
+let segmentIndex = 0;
+
+const ai = new portAudio.AudioIO({
+  inOptions: {
+    channelCount: 1,
+    closeOnError: true,  // Close the stream if an audio error is detected, if
+                         // set false then just log the error
+    deviceId: -1,  // Use -1 or omit the deviceId to select the default device
+    sampleFormat: portAudio.SampleFormatFloat32,
+    sampleRate: recognizer.config.featConfig.sampleRate
+  }
+});
+
+const display = new sherpa_onnx.Display(50);
+
+ai.on('data', data => {
+  const samples = new Float32Array(data.buffer);
+
+  stream.acceptWaveform(
+      {sampleRate: recognizer.config.featConfig.sampleRate, samples: samples});
+
+  while (recognizer.isReady(stream)) {
+    recognizer.decode(stream);
+  }
+
+  const isEndpoint = recognizer.isEndpoint(stream);
+  const text = recognizer.getResult(stream).text.toLowerCase();
+
+  if (text.length > 0 && lastText != text) {
+    lastText = text;
+    display.print(segmentIndex, lastText);
+  }
+  if (isEndpoint) {
+    if (text.length > 0) {
+      lastText = text;
+      segmentIndex += 1;
+    }
+    recognizer.reset(stream)
+  }
+});
+
+ai.on('close', () => {
+  console.log('Free resources');
+  stream.free();
+  recognizer.free();
+});
+
+ai.start();
+console.log('Started! Please speak')

nodejs-addon-examples/test_asr_streaming_ctc_microphone.js

@@ -0,0 +1,88 @@
+// Copyright (c)  2023-2024  Xiaomi Corporation (authors: Fangjun Kuang)
+//
+const portAudio = require('naudiodon2');
+// console.log(portAudio.getDevices());
+
+const sherpa_onnx = require('sherpa-onnx-node');
+
+function createOnlineRecognizer() {
+  const config = {
+    'featConfig': {
+      'sampleRate': 16000,
+      'featureDim': 80,
+    },
+    'modelConfig': {
+      'zipformer2Ctc': {
+        'model':
+            './sherpa-onnx-streaming-zipformer-ctc-small-2024-03-18/ctc-epoch-30-avg-3-chunk-16-left-128.int8.onnx',
+      },
+      'tokens':
+          './sherpa-onnx-streaming-zipformer-ctc-small-2024-03-18/tokens.txt',
+      'numThreads': 2,
+      'provider': 'cpu',
+      'debug': 1,
+    },
+    'decodingMethod': 'greedy_search',
+    'maxActivePaths': 4,
+    'enableEndpoint': true,
+    'rule1MinTrailingSilence': 2.4,
+    'rule2MinTrailingSilence': 1.2,
+    'rule3MinUtteranceLength': 20
+  };
+
+  return new sherpa_onnx.OnlineRecognizer(config);
+}
+
+const recognizer = createOnlineRecognizer();
+const stream = recognizer.createStream();
+
+let lastText = '';
+let segmentIndex = 0;
+
+const ai = new portAudio.AudioIO({
+  inOptions: {
+    channelCount: 1,
+    closeOnError: true,  // Close the stream if an audio error is detected, if
+                         // set false then just log the error
+    deviceId: -1,  // Use -1 or omit the deviceId to select the default device
+    sampleFormat: portAudio.SampleFormatFloat32,
+    sampleRate: recognizer.config.featConfig.sampleRate
+  }
+});
+
+const display = new sherpa_onnx.Display(50);
+
+ai.on('data', data => {
+  const samples = new Float32Array(data.buffer);
+
+  stream.acceptWaveform(
+      {sampleRate: recognizer.config.featConfig.sampleRate, samples: samples});
+
+  while (recognizer.isReady(stream)) {
+    recognizer.decode(stream);
+  }
+
+  const isEndpoint = recognizer.isEndpoint(stream);
+  const text = recognizer.getResult(stream).text.toLowerCase();
+
+  if (text.length > 0 && lastText != text) {
+    lastText = text;
+    display.print(segmentIndex, lastText);
+  }
+  if (isEndpoint) {
+    if (text.length > 0) {
+      lastText = text;
+      segmentIndex += 1;
+    }
+    recognizer.reset(stream)
+  }
+});
+
+ai.on('close', () => {
+  console.log('Free resources');
+  stream.free();
+  recognizer.free();
+});
+
+ai.start();
+console.log('Started! Please speak')

nodejs-addon-examples/test_asr_streaming_transducer.js

@@ -24,7 +24,6 @@ const config = {
     'numThreads': 2,
     'provider': 'cpu',
     'debug': 1,
-    'modelType': 'zipformer',
   }
 };
 
@@ -53,5 +52,8 @@ const duration = wave.samples.length / wave.sampleRate;
 const real_time_factor = elapsed_seconds / duration;
 console.log('Wave duration', duration.toFixed(3), 'secodns')
 console.log('Elapsed', elapsed_seconds.toFixed(3), 'secodns')
-console.log('RTF', real_time_factor.toFixed(3))
-console.log('result', result.text)
+console.log(
+    `RTF = ${elapsed_seconds.toFixed(3)}/${duration.toFixed(3)} =`,
+    real_time_factor.toFixed(3))
+console.log(waveFilename)
+console.log('result\n', result)

nodejs-addon-examples/test_asr_streaming_transducer_microphone.js

@@ -25,7 +25,6 @@ function createOnlineRecognizer() {
       'numThreads': 2,
       'provider': 'cpu',
       'debug': 1,
-      'modelType': 'zipformer',
     },
     'decodingMethod': 'greedy_search',
     'maxActivePaths': 4,
@@ -68,7 +67,7 @@ ai.on('data', data => {
   }
 
   const isEndpoint = recognizer.isEndpoint(stream);
-  const text = recognizer.getResult(stream).text;
+  const text = recognizer.getResult(stream).text.toLowerCase();
 
   if (text.length > 0 && lastText != text) {
     lastText = text;

scripts/apk/generate-tts-apk-script.py

@@ -158,7 +158,7 @@ def get_piper_models() -> List[TtsModel]:
         TtsModel(model_dir="vits-piper-fa_IR-gyro-medium"),
         TtsModel(model_dir="vits-piper-fi_FI-harri-low"),
         TtsModel(model_dir="vits-piper-fi_FI-harri-medium"),
-        TtsModel(model_dir="vits-piper-fr_FR-mls-medium"),
+        #  TtsModel(model_dir="vits-piper-fr_FR-mls-medium"),
         TtsModel(model_dir="vits-piper-fr_FR-siwis-low"),
         TtsModel(model_dir="vits-piper-fr_FR-siwis-medium"),
         TtsModel(model_dir="vits-piper-fr_FR-upmc-medium"),

scripts/node-addon-api/lib/addon.js

@@ -9,6 +9,7 @@ const possible_paths = [
   '../build/Debug/sherpa-onnx.node',
   `./node_modules/sherpa-onnx-${platform_arch}/sherpa-onnx.node`,
   `../sherpa-onnx-${platform_arch}/sherpa-onnx.node`,
+  './sherpa-onnx.node',
 ];
 
 let found = false;

scripts/node-addon-api/run.sh

@@ -0,0 +1,15 @@
+#!/usr/bin/env bash
+
+set -ex
+
+if [[ ! -f ../../build/install/lib/libsherpa-onnx-core.dylib && ! -f ../../build/install/lib/libsherpa-onnx-core.so ]]; then
+  pushd ../../
+  mkdir -p build
+  cd build
+  cmake -DCMAKE_INSTALL_PREFIX=./install -DBUILD_SHARED_LIBS=ON ..
+  make install
+  popd
+fi
+export SHERPA_ONNX_INSTALL_DIR=$PWD/../../build/install
+
+./node_modules/.bin/cmake-js compile

scripts/node-addon-api/src/streaming-asr.cc

@@ -89,6 +89,30 @@ static SherpaOnnxOnlineTransducerModelConfig GetOnlineTransducerModelConfig(
   return config;
 }
 
+static SherpaOnnxOnlineZipformer2CtcModelConfig
+GetOnlineZipformer2CtcModelConfig(Napi::Object obj) {
+  SherpaOnnxOnlineZipformer2CtcModelConfig config;
+  memset(&config, 0, sizeof(config));
+
+  if (!obj.Has("zipformer2Ctc") || !obj.Get("zipformer2Ctc").IsObject()) {
+    return config;
+  }
+
+  Napi::Object o = obj.Get("zipformer2Ctc").As<Napi::Object>();
+
+  if (o.Has("model") && o.Get("model").IsString()) {
+    Napi::String model = o.Get("model").As<Napi::String>();
+    std::string s = model.Utf8Value();
+    char *p = new char[s.size() + 1];
+    std::copy(s.begin(), s.end(), p);
+    p[s.size()] = 0;
+
+    config.model = p;
+  }
+
+  return config;
+}
+
 static SherpaOnnxOnlineModelConfig GetOnlineModelConfig(Napi::Object obj) {
   SherpaOnnxOnlineModelConfig config;
   memset(&config, 0, sizeof(config));
@@ -100,6 +124,7 @@ static SherpaOnnxOnlineModelConfig GetOnlineModelConfig(Napi::Object obj) {
   Napi::Object o = obj.Get("modelConfig").As<Napi::Object>();
 
   config.transducer = GetOnlineTransducerModelConfig(o);
+  config.zipformer2_ctc = GetOnlineZipformer2CtcModelConfig(o);
 
   if (o.Has("tokens") && o.Get("tokens").IsString()) {
     Napi::String tokens = o.Get("tokens").As<Napi::String>();
@@ -147,6 +172,35 @@ static SherpaOnnxOnlineModelConfig GetOnlineModelConfig(Napi::Object obj) {
   return config;
 }
 
+static SherpaOnnxOnlineCtcFstDecoderConfig GetCtcFstDecoderConfig(
+    Napi::Object obj) {
+  SherpaOnnxOnlineCtcFstDecoderConfig config;
+  memset(&config, 0, sizeof(config));
+
+  if (!obj.Has("ctcFstDecoderConfig") ||
+      !obj.Get("ctcFstDecoderConfig").IsObject()) {
+    return config;
+  }
+
+  Napi::Object o = obj.Get("ctcFstDecoderConfig").As<Napi::Object>();
+
+  if (o.Has("graph") && o.Get("graph").IsString()) {
+    Napi::String graph = o.Get("graph").As<Napi::String>();
+    std::string s = graph.Utf8Value();
+    char *p = new char[s.size() + 1];
+    std::copy(s.begin(), s.end(), p);
+    p[s.size()] = 0;
+
+    config.graph = p;
+  }
+
+  if (o.Has("maxActive") && o.Get("maxActive").IsNumber()) {
+    config.max_active = o.Get("maxActive").As<Napi::Number>().Int32Value();
+  }
+
+  return config;
+}
+
 static Napi::External<SherpaOnnxOnlineRecognizer> CreateOnlineRecognizerWrapper(
     const Napi::CallbackInfo &info) {
   Napi::Env env = info.Env();
@@ -234,6 +288,8 @@ static Napi::External<SherpaOnnxOnlineRecognizer> CreateOnlineRecognizerWrapper(
         config.Get("hotwordsScore").As<Napi::Number>().FloatValue();
   }
 
+  c.ctc_fst_decoder_config = GetCtcFstDecoderConfig(config);
+
 #if 0
   printf("encoder: %s\n", c.model_config.transducer.encoder
                               ? c.model_config.transducer.encoder
@@ -277,6 +333,10 @@ static Napi::External<SherpaOnnxOnlineRecognizer> CreateOnlineRecognizerWrapper(
     delete[] c.model_config.transducer.joiner;
   }
 
+  if (c.model_config.zipformer2_ctc.model) {
+    delete[] c.model_config.zipformer2_ctc.model;
+  }
+
   if (c.model_config.tokens) {
     delete[] c.model_config.tokens;
   }
@@ -297,6 +357,10 @@ static Napi::External<SherpaOnnxOnlineRecognizer> CreateOnlineRecognizerWrapper(
     delete[] c.hotwords_file;
   }
 
+  if (c.ctc_fst_decoder_config.graph) {
+    delete[] c.ctc_fst_decoder_config.graph;
+  }
+
   if (!recognizer) {
     Napi::TypeError::New(env, "Please check your config!")
         .ThrowAsJavaScriptException();

sherpa-onnx/csrc/online-recognizer-ctc-impl.h

@@ -216,6 +216,8 @@ class OnlineRecognizerCtcImpl : public OnlineRecognizerImpl {
     // clear states
     s->SetStates(model_->GetInitStates());
 
+    s->GetFasterDecoderProcessedFrames() = 0;
+
     // Note: We only update counters. The underlying audio samples
     // are not discarded.
     s->Reset();