Add Kotlin and Java API for KittenTTS (#2461)

java-api-examples/NonStreamingTtsKittenEn.java

@@ -0,0 +1,60 @@
+// Copyright 2025 Xiaomi Corporation
+
+// This file shows how to use a KittenTTS English model
+// to convert text to speech
+import com.k2fsa.sherpa.onnx.*;
+
+public class NonStreamingTtsKittenEn {
+  public static void main(String[] args) {
+    // please visit
+    // https://k2-fsa.github.io/sherpa/onnx/tts/pretrained_models/kitten.html
+    // to download model files
+    String model = "./kitten-nano-en-v0_1-fp16/model.fp16.onnx";
+    String voices = "./kitten-nano-en-v0_1-fp16/voices.bin";
+    String tokens = "./kitten-nano-en-v0_1-fp16/tokens.txt";
+    String dataDir = "./kitten-nano-en-v0_1-fp16/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.";
+
+    OfflineTtsKittenModelConfig kittenModelConfig =
+        OfflineTtsKittenModelConfig.builder()
+            .setModel(model)
+            .setVoices(voices)
+            .setTokens(tokens)
+            .setDataDir(dataDir)
+            .build();
+
+    OfflineTtsModelConfig modelConfig =
+        OfflineTtsModelConfig.builder()
+            .setKitten(kittenModelConfig)
+            .setNumThreads(2)
+            .setDebug(true)
+            .build();
+
+    OfflineTtsConfig config = OfflineTtsConfig.builder().setModel(modelConfig).build();
+    OfflineTts tts = new OfflineTts(config);
+
+    int sid = 7;
+    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-kitten-en.wav";
+    audio.save(waveFilename);
+    System.out.printf("-- elapsed : %.3f seconds\n", timeElapsedSeconds);
+    System.out.printf("-- audio duration: %.3f seconds\n", audioDuration);
+    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();
+  }
+}