[RNE Rewrite] feat: add Kokoro TTS pipeline implementation

.cspell-wordlist.txt

@@ -314,3 +314,5 @@ Partitioner
 denoised
 ttfa
 TTFA
+phonemized
+subsentences

.github/workflows/clang-tidy.yml

@@ -24,6 +24,11 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v6
+        with:
+          # The phonemis submodule carries headers that cpp/extensions/speech
+          # includes; without it those sources fail to parse and clang-tidy
+          # reports misleading findings on the broken AST.
+          submodules: true
 
       - name: Setup
         uses: ./.github/actions/setup

apps/speech/app/_layout.tsx

@@ -48,6 +48,13 @@ export default function Layout() {
           title: 'Text-to-Speech (SuperTonic)',
         }}
       />
+      <Drawer.Screen
+        name="kokoro-text-to-speech/index"
+        options={{
+          drawerLabel: 'Text-to-Speech (Kokoro)',
+          title: 'Text-to-Speech (Kokoro)',
+        }}
+      />
     </Drawer>
   );
 }

apps/speech/app/index.tsx

@@ -29,6 +29,12 @@ export default function Home() {
         <TouchableOpacity style={styles.button} onPress={() => router.navigate('text-to-speech/')}>
           <Text style={styles.buttonText}>Text-to-Speech (SuperTonic)</Text>
         </TouchableOpacity>
+        <TouchableOpacity
+          style={styles.button}
+          onPress={() => router.navigate('kokoro-text-to-speech/')}
+        >
+          <Text style={styles.buttonText}>Text-to-Speech (Kokoro)</Text>
+        </TouchableOpacity>
       </View>
     </View>
   );

apps/speech/app/kokoro-text-to-speech/index.tsx

@@ -0,0 +1,351 @@
+import React, { useCallback, useEffect, useRef, useState } from 'react';
+import { View, Text, StyleSheet, ScrollView, TextInput } from 'react-native';
+import {
+  useKokoroTextToSpeech,
+  models,
+  KOKORO_SAMPLE_RATE,
+  type KokoroTtsModel,
+} from 'react-native-executorch';
+import { AudioContext, type AudioBufferQueueSourceNode } from 'react-native-audio-api';
+
+import ScreenWrapper from '../../components/ScreenWrapper';
+import { ModelPicker } from '../../components/ModelPicker';
+import { ModelStatus } from '../../components/ModelStatus';
+import { Button } from '../../components/Button';
+import { theme } from '../../theme';
+
+const LANGUAGE_OPTIONS = [
+  { label: 'English (US)', value: 'EN_US' as const },
+  { label: 'English (GB)', value: 'EN_GB' as const },
+  { label: 'Spanish', value: 'ES' as const },
+  { label: 'French', value: 'FR' as const },
+  { label: 'Italian', value: 'IT' as const },
+  { label: 'Portuguese', value: 'PT' as const },
+  { label: 'Hindi', value: 'HI' as const },
+  { label: 'Polish', value: 'PL' as const },
+  { label: 'German', value: 'DE' as const },
+];
+
+type KokoroLanguage = (typeof LANGUAGE_OPTIONS)[number]['value'];
+
+// cspell:disable
+const SAMPLE_TEXTS: Record<KokoroLanguage, string> = {
+  EN_US:
+    'Kokoro is a compact text-to-speech model that runs entirely on your device. ' +
+    'It converts text into phonemes first, then predicts how long each sound should last, ' +
+    'and finally synthesizes the waveform. No internet connection is required.',
+  EN_GB:
+    'Kokoro is a compact text-to-speech model that runs entirely on your device, ' +
+    'converting text into phonemes before synthesising the waveform.',
+  ES: 'Kokoro es un modelo de síntesis de voz que funciona completamente en tu dispositivo, sin conexión a internet.',
+  FR: 'Kokoro est un modèle de synthèse vocale qui fonctionne entièrement sur votre appareil, sans connexion internet.',
+  IT: 'Kokoro è un modello di sintesi vocale che funziona interamente sul tuo dispositivo, senza connessione a internet.',
+  PT: 'Kokoro é um modelo de síntese de voz que funciona inteiramente no seu dispositivo, sem ligação à internet.',
+  HI: 'कोकोरो एक छोटा टेक्स्ट-टू-स्पीच मॉडल है जो पूरी तरह से आपके डिवाइस पर चलता है।',
+  PL: 'Kokoro to niewielki model syntezy mowy, który działa w całości na twoim urządzeniu, bez połączenia z internetem.',
+  DE: 'Kokoro ist ein kompaktes Sprachsynthesemodell, das vollständig auf deinem Gerät läuft, ganz ohne Internetverbindung.',
+};
+// cspell:enable
+
+const SPEED_OPTIONS = [
+  { label: '0.8x', value: 0.8 },
+  { label: '0.9x', value: 0.9 },
+  { label: '1.0x', value: 1.0 },
+  { label: '1.1x', value: 1.1 },
+  { label: '1.25x', value: 1.25 },
+];
+
+function KokoroContent() {
+  const [language, setLanguage] = useState<KokoroLanguage>('EN_US');
+  const [text, setText] = useState(SAMPLE_TEXTS.EN_US);
+  const [speed, setSpeed] = useState(1.0);
+  const [isSynthesizing, setIsSynthesizing] = useState(false);
+  const [isPlaying, setIsPlaying] = useState(false);
+  const [chunkProgress, setChunkProgress] = useState<string | null>(null);
+  const [runError, setRunError] = useState<string | null>(null);
+  const [totalDuration, setTotalDuration] = useState<number | null>(null);
+
+  const model = models.textToSpeech.KOKORO[language] as KokoroTtsModel<string>;
+  const voiceNames = Object.keys(model.voices);
+  const [voice, setVoice] = useState(voiceNames[0]!);
+
+  const audioCtxRef = useRef<AudioContext | null>(null);
+  const queueSourceRef = useRef<AudioBufferQueueSourceNode | null>(null);
+
+  const { isReady, downloadProgress, error, synthesize, synthesizeStop } =
+    useKokoroTextToSpeech(model);
+
+  useEffect(() => {
+    setVoice(Object.keys(models.textToSpeech.KOKORO[language].voices)[0]!);
+    setText(SAMPLE_TEXTS[language]);
+  }, [language]);
+
+  const getAudioContext = useCallback(async () => {
+    if (!audioCtxRef.current || audioCtxRef.current.state === 'closed') {
+      audioCtxRef.current = new AudioContext({ sampleRate: KOKORO_SAMPLE_RATE });
+    }
+    if (audioCtxRef.current.state === 'suspended') {
+      await audioCtxRef.current.resume();
+    }
+    return audioCtxRef.current;
+  }, []);
+
+  const stopAudioQueue = useCallback(() => {
+    if (queueSourceRef.current) {
+      queueSourceRef.current.clearBuffers();
+      queueSourceRef.current.stop();
+      queueSourceRef.current = null;
+    }
+    setIsPlaying(false);
+  }, []);
+
+  useEffect(() => {
+    return () => {
+      synthesizeStop?.();
+      stopAudioQueue();
+      if (audioCtxRef.current) {
+        audioCtxRef.current.close().catch(() => {});
+        audioCtxRef.current = null;
+      }
+    };
+  }, [stopAudioQueue, synthesizeStop]);
+
+  const preparePlaybackSource = useCallback(async () => {
+    stopAudioQueue();
+    const ctx = await getAudioContext();
+
+    const source = ctx.createBufferQueueSource();
+    source.connect(ctx.destination);
+    source.onBufferEnded = (event) => {
+      if (event.isLastBufferInQueue) setIsPlaying(false);
+    };
+    queueSourceRef.current = source;
+    return { ctx, source };
+  }, [getAudioContext, stopAudioQueue]);
+
+  const handleSynthesize = async () => {
+    if (!synthesize || isSynthesizing || !text.trim()) return;
+
+    setRunError(null);
+    setChunkProgress(null);
+    setTotalDuration(null);
+    setIsSynthesizing(true);
+
+    try {
+      const { ctx, source } = await preparePlaybackSource();
+      let durationSum = 0;
+      let started = false;
+
+      for await (const chunk of synthesize(text, { voice, speed })) {
+        setChunkProgress(
+          `Chunk ${chunk.chunkIndex + 1}/${chunk.totalChunks} (${chunk.duration.toFixed(1)}s)`
+        );
+        durationSum += chunk.duration;
+
+        const buffer = ctx.createBuffer(1, chunk.audio.length, KOKORO_SAMPLE_RATE);
+        buffer.copyToChannel(chunk.audio as Float32Array<ArrayBuffer>, 0);
+        source.enqueueBuffer(buffer);
+
+        if (!started) {
+          started = true;
+          setIsPlaying(true);
+          source.start(0, 0);
+        }
+      }
+
+      setTotalDuration(durationSum);
+      setChunkProgress(null);
+    } catch (err) {
+      setRunError(err instanceof Error ? err.message : String(err));
+    } finally {
+      setIsSynthesizing(false);
+    }
+  };
+
+  const handleStopPlayback = () => {
+    synthesizeStop?.();
+    stopAudioQueue();
+    setIsSynthesizing(false);
+  };
+
+  const isBusy = isSynthesizing || isPlaying;
+
+  return (
+    <ScrollView style={styles.container} contentContainerStyle={styles.content}>
+      <View style={styles.card}>
+        <Text style={styles.cardTitle}>Kokoro Text-to-Speech</Text>
+        <Text style={styles.cardDescription}>
+          Phoneme-driven on-device speech synthesis. Pick a language to load its model, phonemizer
+          assets and voices.
+        </Text>
+        <ModelStatus
+          isReady={isReady}
+          downloadProgress={downloadProgress}
+          error={error ? error.message : null}
+          modelTypeLabel="Kokoro TTS models"
+        />
+      </View>
+
+      {runError && (
+        <View style={styles.errorContainer}>
+          <Text style={styles.errorText}>{runError}</Text>
+        </View>
+      )}
+
+      <View style={styles.card}>
+        <ModelPicker
+          label="Language"
+          options={LANGUAGE_OPTIONS.map((l) => ({ ...l, disabled: isBusy }))}
+          selectedValue={language}
+          onValueChange={setLanguage}
+        />
+        <ModelPicker
+          label="Voice"
+          options={voiceNames.map((name) => ({ label: name, value: name, disabled: isBusy }))}
+          selectedValue={voice}
+          onValueChange={setVoice}
+        />
+        <ModelPicker
+          label="Speed"
+          options={SPEED_OPTIONS.map((s) => ({ ...s, disabled: isBusy }))}
+          selectedValue={speed}
+          onValueChange={setSpeed}
+        />
+      </View>
+
+      <View style={styles.card}>
+        <Text style={styles.sectionTitle}>Input Text</Text>
+        <TextInput
+          style={styles.textInput}
+          value={text}
+          onChangeText={setText}
+          placeholder="Enter text to synthesize..."
+          placeholderTextColor={theme.colors.textPlaceholder}
+          multiline
+          numberOfLines={4}
+          editable={!isBusy}
+        />
+      </View>
+
+      <View style={styles.card}>
+        <View style={styles.buttonRow}>
+          {!isPlaying ? (
+            <Button
+              title={isSynthesizing ? 'Synthesizing...' : 'Synthesize & Play'}
+              onPress={handleSynthesize}
+              disabled={!isReady || !text.trim() || isBusy}
+              loading={isSynthesizing}
+            />
+          ) : (
+            <Button title="Stop Playback" variant="accent" onPress={handleStopPlayback} />
+          )}
+        </View>
+
+        {chunkProgress && (
+          <View style={styles.progressContainer}>
+            <Text style={styles.progressText}>{chunkProgress}</Text>
+          </View>
+        )}
+
+        {totalDuration !== null && !isSynthesizing && (
+          <View style={styles.resultContainer}>
+            <Text style={styles.resultText}>
+              Generated {totalDuration.toFixed(1)}s of audio at {KOKORO_SAMPLE_RATE} Hz
+            </Text>
+          </View>
+        )}
+      </View>
+    </ScrollView>
+  );
+}
+
+export default function KokoroScreen() {
+  return (
+    <ScreenWrapper>
+      <KokoroContent />
+    </ScreenWrapper>
+  );
+}
+
+const styles = StyleSheet.create({
+  container: { flex: 1, backgroundColor: theme.colors.background },
+  content: { padding: theme.spacing.large, paddingBottom: 40 },
+  card: {
+    backgroundColor: theme.colors.cardBackground,
+    borderRadius: theme.radius.large,
+    padding: 20,
+    marginBottom: 20,
+    borderWidth: 1,
+    borderColor: theme.colors.lightBorder,
+  },
+  cardTitle: {
+    fontSize: theme.typography.title.fontSize,
+    fontWeight: theme.typography.title.fontWeight,
+    color: theme.colors.strongPrimary,
+    marginBottom: 8,
+  },
+  cardDescription: {
+    fontSize: 14,
+    color: theme.colors.textMuted,
+    lineHeight: 20,
+    marginBottom: 16,
+  },
+  sectionTitle: {
+    fontSize: 16,
+    fontWeight: '700',
+    color: '#212529',
+    marginBottom: 10,
+  },
+  textInput: {
+    height: 120,
+    borderColor: theme.colors.border,
+    borderWidth: 1,
+    borderRadius: theme.radius.small,
+    paddingHorizontal: 12,
+    paddingVertical: 10,
+    color: theme.colors.textSecondary,
+    backgroundColor: theme.colors.background,
+    fontSize: 14,
+    lineHeight: 20,
+    textAlignVertical: 'top',
+  },
+  buttonRow: {
+    flexDirection: 'row',
+    gap: theme.spacing.small,
+  },
+  progressContainer: {
+    marginTop: 12,
+    padding: 10,
+    backgroundColor: '#e8f4fd',
+    borderRadius: theme.radius.small,
+  },
+  progressText: {
+    fontSize: 13,
+    color: '#1a73e8',
+    fontWeight: '500',
+    textAlign: 'center',
+  },
+  resultContainer: {
+    marginTop: 12,
+    padding: 10,
+    backgroundColor: '#e6f9e6',
+    borderRadius: theme.radius.small,
+  },
+  resultText: {
+    fontSize: 13,
+    color: '#2e7d32',
+    fontWeight: '500',
+    textAlign: 'center',
+  },
+  errorContainer: {
+    backgroundColor: theme.colors.errorBackground,
+    padding: 12,
+    borderRadius: theme.radius.small,
+    marginBottom: 20,
+  },
+  errorText: {
+    color: theme.colors.errorText,
+    fontSize: 14,
+    textAlign: 'center',
+  },
+});