Add streaming ASR example from a microphone for Java API (#1047)

java-api-examples/README.md

@@ -7,6 +7,7 @@ This directory contains examples for the JAVA API of sherpa-onnx.
 ## Streaming Speech recognition
 
 ```
+./run-streaming-asr-from-mic-transducer.sh
 ./run-streaming-decode-file-ctc.sh
 ./run-streaming-decode-file-ctc-hlg.sh
 ./run-streaming-decode-file-paraformer.sh

java-api-examples/StreamingAsrFromMicTransducer.java

@@ -0,0 +1,117 @@
+// Copyright 2022-2023 by zhaoming
+// Copyright 2024 Xiaomi Corporation
+
+// This file shows how to use an online transducer, i.e., streaming transducer,
+// for real-time speech recognition with a microphone.
+import com.k2fsa.sherpa.onnx.*;
+import javax.sound.sampled.*;
+
+public class StreamingAsrFromMicTransducer {
+  public static void main(String[] args) {
+    // please refer to
+    // https://k2-fsa.github.io/sherpa/onnx/pretrained_models/online-transducer/zipformer-transducer-models.html#csukuangfj-sherpa-onnx-streaming-zipformer-bilingual-zh-en-2023-02-20-bilingual-chinese-english
+    // to download model files
+    String encoder =
+        "./sherpa-onnx-streaming-zipformer-bilingual-zh-en-2023-02-20/encoder-epoch-99-avg-1.int8.onnx";
+    String decoder =
+        "./sherpa-onnx-streaming-zipformer-bilingual-zh-en-2023-02-20/decoder-epoch-99-avg-1.onnx";
+    String joiner =
+        "./sherpa-onnx-streaming-zipformer-bilingual-zh-en-2023-02-20/joiner-epoch-99-avg-1.onnx";
+    String tokens = "./sherpa-onnx-streaming-zipformer-bilingual-zh-en-2023-02-20/tokens.txt";
+
+    // https://github.com/k2-fsa/sherpa-onnx/releases/download/asr-models/itn_zh_number.fst
+    String ruleFsts = "./itn_zh_number.fst";
+
+    int sampleRate = 16000;
+
+    OnlineTransducerModelConfig transducer =
+        OnlineTransducerModelConfig.builder()
+            .setEncoder(encoder)
+            .setDecoder(decoder)
+            .setJoiner(joiner)
+            .build();
+
+    OnlineModelConfig modelConfig =
+        OnlineModelConfig.builder()
+            .setTransducer(transducer)
+            .setTokens(tokens)
+            .setNumThreads(1)
+            .setDebug(true)
+            .build();
+
+    OnlineRecognizerConfig config =
+        OnlineRecognizerConfig.builder()
+            .setOnlineModelConfig(modelConfig)
+            .setDecodingMethod("greedy_search")
+            .setRuleFsts(ruleFsts)
+            .build();
+
+    OnlineRecognizer recognizer = new OnlineRecognizer(config);
+    OnlineStream stream = recognizer.createStream();
+
+    // https://docs.oracle.com/javase/8/docs/api/javax/sound/sampled/AudioFormat.html
+    // Linear PCM, 16000Hz, 16-bit, 1 channel, signed, little endian
+    AudioFormat format = new AudioFormat(sampleRate, 16, 1, true, false);
+
+    // https://docs.oracle.com/javase/8/docs/api/javax/sound/sampled/DataLine.Info.html#Info-java.lang.Class-javax.sound.sampled.AudioFormat-int-
+    DataLine.Info info = new DataLine.Info(TargetDataLine.class, format);
+    TargetDataLine targetDataLine;
+    try {
+      targetDataLine = (TargetDataLine) AudioSystem.getLine(info);
+      targetDataLine.open(format);
+      targetDataLine.start();
+    } catch (LineUnavailableException e) {
+      System.out.println("Failed to open target data line: " + e.getMessage());
+      recognizer.release();
+      stream.release();
+      return;
+    }
+
+    String lastText = "";
+    int segmentIndex = 0;
+
+    // You can choose an arbitrary number
+    int bufferSize = 1600; // 0.1 seconds for 16000Hz
+    byte[] buffer = new byte[bufferSize * 2]; // a short has 2 bytes
+    float[] samples = new float[bufferSize];
+
+    System.out.println("Started! Please speak");
+    while (targetDataLine.isOpen()) {
+      int n = targetDataLine.read(buffer, 0, buffer.length);
+      if (n <= 0) {
+        System.out.printf("Got %d bytes. Expected %d bytes.\n", n, buffer.length);
+        continue;
+      }
+      for (int i = 0; i != bufferSize; ++i) {
+        short low = buffer[2 * i];
+        short high = buffer[2 * i + 1];
+        int s = (high << 8) + low;
+        samples[i] = (float) s / 32768;
+      }
+      stream.acceptWaveform(samples, sampleRate);
+
+      while (recognizer.isReady(stream)) {
+        recognizer.decode(stream);
+      }
+
+      String text = recognizer.getResult(stream).getText();
+      boolean isEndpoint = recognizer.isEndpoint(stream);
+      if (!text.isEmpty() && text != " " && lastText != text) {
+        lastText = text;
+        System.out.printf("%d: %s\r", segmentIndex, text);
+      }
+
+      if (isEndpoint) {
+        if (!text.isEmpty()) {
+          System.out.println();
+          segmentIndex += 1;
+        }
+
+        recognizer.reset(stream);
+      }
+    } // while (targetDataLine.isOpen())
+
+    stream.release();
+    recognizer.release();
+  }
+}

java-api-examples/run-streaming-asr-from-mic-transducer.sh

@@ -0,0 +1,55 @@
+#!/usr/bin/env bash
+
+set -ex
+
+if [[ ! -f ../build/lib/libsherpa-onnx-jni.dylib  && ! -f ../build/lib/libsherpa-onnx-jni.so ]]; then
+  mkdir -p ../build
+  pushd ../build
+  cmake \
+    -DSHERPA_ONNX_ENABLE_PYTHON=OFF \
+    -DSHERPA_ONNX_ENABLE_TESTS=OFF \
+    -DSHERPA_ONNX_ENABLE_CHECK=OFF \
+    -DBUILD_SHARED_LIBS=ON \
+    -DSHERPA_ONNX_ENABLE_PORTAUDIO=OFF \
+    -DSHERPA_ONNX_ENABLE_JNI=ON \
+    ..
+
+  make -j4
+  ls -lh lib
+  popd
+fi
+
+if [ ! -f ../sherpa-onnx/java-api/build/sherpa-onnx.jar ]; then
+  pushd ../sherpa-onnx/java-api
+  make
+  popd
+fi
+
+if [[ ! -f ../build/lib/libsherpa-onnx-jni.dylib  && ! -f ../build/lib/libsherpa-onnx-jni.so ]]; then
+  cmake \
+    -DSHERPA_ONNX_ENABLE_PYTHON=OFF \
+    -DSHERPA_ONNX_ENABLE_TESTS=OFF \
+    -DSHERPA_ONNX_ENABLE_CHECK=OFF \
+    -DBUILD_SHARED_LIBS=ON \
+    -DSHERPA_ONNX_ENABLE_PORTAUDIO=OFF \
+    -DSHERPA_ONNX_ENABLE_JNI=ON \
+    ..
+
+  make -j4
+  ls -lh lib
+fi
+
+if [ ! -f ./sherpa-onnx-streaming-zipformer-bilingual-zh-en-2023-02-20/tokens.txt ]; then
+  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
+fi
+
+if [ ! -f ./itn_zh_number.fst ]; then
+  curl -SL -O https://github.com/k2-fsa/sherpa-onnx/releases/download/asr-models/itn_zh_number.fst
+fi
+
+java \
+  -Djava.library.path=$PWD/../build/lib \
+  -cp ../sherpa-onnx/java-api/build/sherpa-onnx.jar \
+  ./StreamingAsrFromMicTransducer.java