Add Koltin and Java API for Kokoro TTS models (#1728)

sherpa-onnx/java-api/Makefile

@@ -35,6 +35,7 @@ java_files += OfflineRecognizerResult.java
 java_files += OfflineStream.java
 java_files += OfflineRecognizer.java
 
+java_files += OfflineTtsKokoroModelConfig.java
 java_files += OfflineTtsMatchaModelConfig.java
 java_files += OfflineTtsVitsModelConfig.java
 java_files += OfflineTtsModelConfig.java

sherpa-onnx/java-api/src/com/k2fsa/sherpa/onnx/OfflineTtsKokoroModelConfig.java

@@ -0,0 +1,80 @@
+// Copyright 2025 Xiaomi Corporation
+package com.k2fsa.sherpa.onnx;
+
+public class OfflineTtsKokoroModelConfig {
+    private final String model;
+    private final String voices;
+    private final String tokens;
+    private final String dataDir;
+    private final float lengthScale;
+
+    private OfflineTtsKokoroModelConfig(Builder builder) {
+        this.model = builder.model;
+        this.voices = builder.voices;
+        this.tokens = builder.tokens;
+        this.dataDir = builder.dataDir;
+        this.lengthScale = builder.lengthScale;
+    }
+
+    public static Builder builder() {
+        return new Builder();
+    }
+
+    public String getModel() {
+        return model;
+    }
+
+    public String getVoices() {
+        return voices;
+    }
+
+    public String getTokens() {
+        return tokens;
+    }
+
+    public String getDataDir() {
+        return dataDir;
+    }
+
+    public float getLengthScale() {
+        return lengthScale;
+    }
+
+
+    public static class Builder {
+        private String model = "";
+        private String voices = "";
+        private String tokens = "";
+        private String dataDir = "";
+        private float lengthScale = 1.0f;
+
+        public OfflineTtsKokoroModelConfig build() {
+            return new OfflineTtsKokoroModelConfig(this);
+        }
+
+        public Builder setModel(String model) {
+            this.model = model;
+            return this;
+        }
+
+        public Builder setVoices(String voices) {
+            this.voices = voices;
+            return this;
+        }
+
+        public Builder setTokens(String tokens) {
+            this.tokens = tokens;
+            return this;
+        }
+
+        public Builder setDataDir(String dataDir) {
+            this.dataDir = dataDir;
+            return this;
+        }
+
+        public Builder setLengthScale(float lengthScale) {
+            this.lengthScale = lengthScale;
+            return this;
+        }
+    }
+}

sherpa-onnx/java-api/src/com/k2fsa/sherpa/onnx/OfflineTtsModelConfig.java

@@ -5,6 +5,7 @@ package com.k2fsa.sherpa.onnx;
 public class OfflineTtsModelConfig {
     private final OfflineTtsVitsModelConfig vits;
     private final OfflineTtsMatchaModelConfig matcha;
+    private final OfflineTtsKokoroModelConfig kokoro;
     private final int numThreads;
     private final boolean debug;
     private final String provider;
@@ -12,6 +13,7 @@ public class OfflineTtsModelConfig {
     private OfflineTtsModelConfig(Builder builder) {
         this.vits = builder.vits;
         this.matcha = builder.matcha;
+        this.kokoro = builder.kokoro;
         this.numThreads = builder.numThreads;
         this.debug = builder.debug;
         this.provider = builder.provider;
@@ -29,9 +31,14 @@ public class OfflineTtsModelConfig {
         return matcha;
     }
 
+    public OfflineTtsKokoroModelConfig getKokoro() {
+        return kokoro;
+    }
+
     public static class Builder {
         private OfflineTtsVitsModelConfig vits = OfflineTtsVitsModelConfig.builder().build();
         private OfflineTtsMatchaModelConfig matcha = OfflineTtsMatchaModelConfig.builder().build();
+        private OfflineTtsKokoroModelConfig kokoro = OfflineTtsKokoroModelConfig.builder().build();
         private int numThreads = 1;
         private boolean debug = true;
         private String provider = "cpu";
@@ -50,6 +57,11 @@ public class OfflineTtsModelConfig {
             return this;
         }
 
+        public Builder setKokoro(OfflineTtsKokoroModelConfig kokoro) {
+            this.kokoro = kokoro;
+            return this;
+        }
+
         public Builder setNumThreads(int numThreads) {
             this.numThreads = numThreads;
             return this;

sherpa-onnx/jni/offline-tts.cc

@@ -113,6 +113,39 @@ static OfflineTtsConfig GetOfflineTtsConfig(JNIEnv *env, jobject config) {
   fid = env->GetFieldID(matcha_cls, "lengthScale", "F");
   ans.model.matcha.length_scale = env->GetFloatField(matcha, fid);
 
+  // kokoro
+  fid = env->GetFieldID(model_config_cls, "kokoro",
+                        "Lcom/k2fsa/sherpa/onnx/OfflineTtsKokoroModelConfig;");
+  jobject kokoro = env->GetObjectField(model, fid);
+  jclass kokoro_cls = env->GetObjectClass(kokoro);
+
+  fid = env->GetFieldID(kokoro_cls, "model", "Ljava/lang/String;");
+  s = (jstring)env->GetObjectField(kokoro, fid);
+  p = env->GetStringUTFChars(s, nullptr);
+  ans.model.kokoro.model = p;
+  env->ReleaseStringUTFChars(s, p);
+
+  fid = env->GetFieldID(kokoro_cls, "voices", "Ljava/lang/String;");
+  s = (jstring)env->GetObjectField(kokoro, fid);
+  p = env->GetStringUTFChars(s, nullptr);
+  ans.model.kokoro.voices = p;
+  env->ReleaseStringUTFChars(s, p);
+
+  fid = env->GetFieldID(kokoro_cls, "tokens", "Ljava/lang/String;");
+  s = (jstring)env->GetObjectField(kokoro, fid);
+  p = env->GetStringUTFChars(s, nullptr);
+  ans.model.kokoro.tokens = p;
+  env->ReleaseStringUTFChars(s, p);
+
+  fid = env->GetFieldID(kokoro_cls, "dataDir", "Ljava/lang/String;");
+  s = (jstring)env->GetObjectField(kokoro, fid);
+  p = env->GetStringUTFChars(s, nullptr);
+  ans.model.kokoro.data_dir = p;
+  env->ReleaseStringUTFChars(s, p);
+
+  fid = env->GetFieldID(kokoro_cls, "lengthScale", "F");
+  ans.model.kokoro.length_scale = env->GetFloatField(kokoro, fid);
+
   fid = env->GetFieldID(model_config_cls, "numThreads", "I");
   ans.model.num_threads = env->GetIntField(model, fid);
 
@@ -273,8 +306,8 @@ Java_com_k2fsa_sherpa_onnx_OfflineTts_generateWithCallbackImpl(
     return env->CallIntMethod(should_continue, int_value_mid);
   };
 
-  auto audio = reinterpret_cast<sherpa_onnx::OfflineTts *>(ptr)->Generate(
-      p_text, sid, speed, callback_wrapper);
+  auto tts = reinterpret_cast<sherpa_onnx::OfflineTts *>(ptr);
+  auto audio = tts->Generate(p_text, sid, speed, callback_wrapper);
 
   jfloatArray samples_arr = env->NewFloatArray(audio.samples.size());
   env->SetFloatArrayRegion(samples_arr, 0, audio.samples.size(),

sherpa-onnx/kotlin-api/Tts.kt

@@ -25,9 +25,18 @@ data class OfflineTtsMatchaModelConfig(
     var lengthScale: Float = 1.0f,
 )
 
+data class OfflineTtsKokoroModelConfig(
+    var model: String = "",
+    var voices: String = "",
+    var tokens: String = "",
+    var dataDir: String = "",
+    var lengthScale: Float = 1.0f,
+)
+
 data class OfflineTtsModelConfig(
     var vits: OfflineTtsVitsModelConfig = OfflineTtsVitsModelConfig(),
     var matcha: OfflineTtsMatchaModelConfig = OfflineTtsMatchaModelConfig(),
+    var kokoro: OfflineTtsKokoroModelConfig = OfflineTtsKokoroModelConfig(),
     var numThreads: Int = 1,
     var debug: Boolean = false,
     var provider: String = "cpu",
@@ -176,12 +185,32 @@ fun getOfflineTtsConfig(
     modelName: String, // for VITS
     acousticModelName: String, // for Matcha
     vocoder: String, // for Matcha
+    voices: String, // for Kokoro
     lexicon: String,
     dataDir: String,
     dictDir: String,
     ruleFsts: String,
-    ruleFars: String
+    ruleFars: String,
+    numThreads: Int? = null
 ): OfflineTtsConfig {
+    // For Matcha TTS, please set
+    // acousticModelName, vocoder
+
+    // For Kokoro TTS, please set
+    // modelName, voices
+
+    // For VITS, please set
+    // modelName
+
+    val numberOfThreads = if (numThreads != null) {
+        numThreads
+    } else if (voices.isNotEmpty()) {
+        // for Kokoro TTS models, we use more threads
+        4
+    } else {
+        2
+    }
+
     if (modelName.isEmpty() && acousticModelName.isEmpty()) {
         throw IllegalArgumentException("Please specify a TTS model")
     }
@@ -193,7 +222,8 @@ fun getOfflineTtsConfig(
     if (acousticModelName.isNotEmpty() && vocoder.isEmpty()) {
         throw IllegalArgumentException("Please provide vocoder for Matcha TTS")
     }
-    val vits = if (modelName.isNotEmpty()) {
+
+    val vits = if (modelName.isNotEmpty() && voices.isEmpty()) {
         OfflineTtsVitsModelConfig(
             model = "$modelDir/$modelName",
             lexicon = "$modelDir/$lexicon",
@@ -218,11 +248,23 @@ fun getOfflineTtsConfig(
         OfflineTtsMatchaModelConfig()
     }
 
+    val kokoro = if (voices.isNotEmpty()) {
+        OfflineTtsKokoroModelConfig(
+            model = "$modelDir/$modelName",
+            voices = "$modelDir/$voices",
+            tokens = "$modelDir/tokens.txt",
+            dataDir = dataDir,
+        )
+    } else {
+        OfflineTtsKokoroModelConfig()
+    }
+
     return OfflineTtsConfig(
         model = OfflineTtsModelConfig(
             vits = vits,
             matcha = matcha,
-            numThreads = 2,
+            kokoro = kokoro,
+            numThreads = numberOfThreads,
             debug = true,
             provider = "cpu",
         ),