Add Java API for text-to-speech (#811)

java-api-examples/NonStreamingTtsPiperEn.java

@@ -0,0 +1,58 @@
+// Copyright 2024 Xiaomi Corporation
+
+// This file shows how to use a piper VITS English TTS model
+// to convert text to speech
+import com.k2fsa.sherpa.onnx.*;
+
+public class NonStreamingTtsPiperEn {
+  public static void main(String[] args) {
+    // please visit
+    // https://github.com/k2-fsa/sherpa-onnx/releases/tag/tts-models
+    // to download model files
+    String model = "./vits-piper-en_GB-cori-medium/en_GB-cori-medium.onnx";
+    String tokens = "./vits-piper-en_GB-cori-medium/tokens.txt";
+    String dataDir = "./vits-piper-en_GB-cori-medium/espeak-ng-data";
+    String text =
+        "Today as always, men fall into two groups: slaves and free men. Whoever does not have"
+            + " two-thirds of his day for himself, is a slave, whatever he may be: a statesman, a"
+            + " businessman, an official, or a scholar.";
+
+    OfflineTtsVitsModelConfig vitsModelConfig =
+        OfflineTtsVitsModelConfig.builder()
+            .setModel(model)
+            .setTokens(tokens)
+            .setDataDir(dataDir)
+            .build();
+
+    OfflineTtsModelConfig modelConfig =
+        OfflineTtsModelConfig.builder()
+            .setVits(vitsModelConfig)
+            .setNumThreads(1)
+            .setDebug(true)
+            .build();
+
+    OfflineTtsConfig config = OfflineTtsConfig.builder().setModel(modelConfig).build();
+    OfflineTts tts = new OfflineTts(config);
+
+    int sid = 0;
+    float speed = 1.0f;
+    long start = System.currentTimeMillis();
+    GeneratedAudio audio = tts.generate(text, sid, speed);
+    long stop = System.currentTimeMillis();
+
+    float timeElapsedSeconds = (stop - start) / 1000.0f;
+
+    float audioDuration = audio.getSamples().length / (float) audio.getSampleRate();
+    float real_time_factor = timeElapsedSeconds / audioDuration;
+
+    String waveFilename = "tts-piper-en.wav";
+    audio.save(waveFilename);
+    System.out.printf("-- elapsed : %.3f seconds\n", timeElapsedSeconds);
+    System.out.printf("-- audio duration: %.3f seconds\n", timeElapsedSeconds);
+    System.out.printf("-- real-time factor (RTF): %.3f\n", real_time_factor);
+    System.out.printf("-- text: %s\n", text);
+    System.out.printf("-- Saved to %s\n", waveFilename);
+
+    tts.release();
+  }
+}