support nodejs (#438)

nodejs-examples/test-offline-paraformer.js

@@ -0,0 +1,95 @@
+// Copyright (c)  2023  Xiaomi Corporation (authors: Fangjun Kuang)
+
+const fs = require('fs');
+const {Readable} = require('stream');
+const wav = require('wav');
+
+const sherpa_onnx = require('sherpa-onnx');
+
+function createRecognizer() {
+  const featConfig = new sherpa_onnx.FeatureConfig();
+  featConfig.sampleRate = 16000;
+  featConfig.featureDim = 80;
+
+  // test online recognizer
+  const paraformer = new sherpa_onnx.OfflineParaformerModelConfig();
+  paraformer.model = './sherpa-onnx-paraformer-zh-2023-03-28/model.onnx';
+  const tokens = './sherpa-onnx-paraformer-zh-2023-03-28/tokens.txt';
+
+  const modelConfig = new sherpa_onnx.OfflineModelConfig();
+  modelConfig.paraformer = paraformer;
+  modelConfig.tokens = tokens;
+  modelConfig.modelType = 'paraformer';
+
+  const recognizerConfig = new sherpa_onnx.OfflineRecognizerConfig();
+  recognizerConfig.featConfig = featConfig;
+  recognizerConfig.modelConfig = modelConfig;
+  recognizerConfig.decodingMethod = 'greedy_search';
+
+  const recognizer = new sherpa_onnx.OfflineRecognizer(recognizerConfig);
+  return recognizer;
+}
+
+recognizer = createRecognizer();
+stream = recognizer.createStream();
+
+const waveFilename = './sherpa-onnx-paraformer-zh-2023-03-28/test_wavs/0.wav';
+
+const reader = new wav.Reader();
+const readable = new Readable().wrap(reader);
+const buf = [];
+
+reader.on('format', ({audioFormat, bitDepth, channels, sampleRate}) => {
+  if (sampleRate != recognizer.config.featConfig.sampleRate) {
+    throw new Error(`Only support sampleRate ${
+        recognizer.config.featConfig.sampleRate}. Given ${sampleRate}`);
+  }
+
+  if (audioFormat != 1) {
+    throw new Error(`Only support PCM format. Given ${audioFormat}`);
+  }
+
+  if (channels != 1) {
+    throw new Error(`Only a single channel. Given ${channel}`);
+  }
+
+  if (bitDepth != 16) {
+    throw new Error(`Only support 16-bit samples. Given ${bitDepth}`);
+  }
+});
+
+fs.createReadStream(waveFilename, {'highWaterMark': 4096})
+    .pipe(reader)
+    .on('finish', function(err) {
+      // tail padding
+      const floatSamples =
+          new Float32Array(recognizer.config.featConfig.sampleRate * 0.5);
+
+      buf.push(floatSamples);
+      const flattened =
+          Float32Array.from(buf.reduce((a, b) => [...a, ...b], []));
+
+      stream.acceptWaveform(recognizer.config.featConfig.sampleRate, flattened);
+      recognizer.decode(stream);
+      const r = recognizer.getResult(stream);
+      console.log(r.text);
+
+      stream.free();
+      recognizer.free();
+    });
+
+readable.on('readable', function() {
+  let chunk;
+  while ((chunk = readable.read()) != null) {
+    const int16Samples = new Int16Array(
+        chunk.buffer, chunk.byteOffset,
+        chunk.length / Int16Array.BYTES_PER_ELEMENT);
+
+    const floatSamples = new Float32Array(int16Samples.length);
+    for (let i = 0; i < floatSamples.length; i++) {
+      floatSamples[i] = int16Samples[i] / 32768.0;
+    }
+
+    buf.push(floatSamples);
+  }
+});