Add Android TTS Engine APK for KittenTTS

[csukuangfj]

You can download the pre-built APK from
https://k2-fsa.github.io/sherpa/onnx/tts/apk-engine.html

Summary by CodeRabbit

• New Features
  • Added support for a new "kitten-nano-en-v0_1-fp16" text-to-speech model, including configuration options and build script integration.
• Chores
  • Enhanced build scripts to recognize and handle the new model type automatically during APK generation.

[coderabbitai]

Caution

Review failed

The pull request is closed.

Walkthrough

A new isKitten boolean flag is introduced throughout the Android TTS app, engine, build scripts, and model generation pipeline to support configuration and selection of the "kitten" TTS model. Template instantiations for Kitten model metadata are also added in the C++ phonemizer component. No major logic or control flow changes are present.

Changes

Cohort / File(s)	Change Summary
Android App: Kitten Model Flag & Config android/SherpaOnnxTts/app/src/main/java/com/k2fsa/sherpa/onnx/MainActivity.kt	Introduces isKitten boolean, adds commented Kitten model config, and passes isKitten to getOfflineTtsConfig().
Android Engine: Kitten Model Flag & Config android/SherpaOnnxTtsEngine/app/src/main/java/com/k2fsa/sherpa/onnx/tts/engine/TtsEngine.kt	Adds private isKitten variable, commented Kitten model example, and updates getOfflineTtsConfig call to include isKitten.
Build Scripts: Kitten Flag Injection scripts/apk/build-apk-tts-engine.sh.in, scripts/apk/build-apk-tts.sh.in	Adds conditional logic to replace isKitten = false with isKitten = true in engine and app source files if the TTS model has the is_kitten attribute set.
Model Generation: Kitten Model Support scripts/apk/generate-tts-apk-script.py	Adds is_kitten boolean to TtsModel dataclass, introduces get_kitten_models() to define Kitten models, and aggregates them with other models.
Phonemizer C++: Kitten Metadata Instantiations sherpa-onnx/csrc/piper-phonemize-lexicon.cc	Adds explicit template instantiations for PiperPhonemizeLexicon constructors supporting OfflineTtsKittenModelMetaData for both Android and OHOS resource managers.

Sequence Diagram(s)

sequenceDiagram
    participant User
    participant MainActivity
    participant TtsEngine
    participant getOfflineTtsConfig

    User->>MainActivity: Selects TTS model (Kitten or other)
    MainActivity->>TtsEngine: initTts(isKitten)
    TtsEngine->>getOfflineTtsConfig: Passes isKitten flag
    getOfflineTtsConfig-->>TtsEngine: Returns config for selected model
    TtsEngine-->>MainActivity: TTS engine ready with Kitten support if enabled

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Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~15 minutes

Possibly related PRs

• Add Kotlin and Java API for KittenTTS #2461: Adds Kotlin/Java API examples and JNI support for KittenTTS, directly extending the Kitten model configuration introduced here.
• Add C++ runtime for kitten-tts #2460: Implements the C++ runtime, config, metadata, and phonemizer support for Kitten TTS, complementing the configuration and integration changes in this PR.

Poem

A flag for kittens, what a treat,
Now TTS purrs with voices sweet.
Scripts and configs, all in tune,
Kitten models coming soon!
With code and care, we hop ahead—
🐾 Let’s make our TTS well-fed!
—A happy rabbit, code well-read.

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📜 Recent review details

Configuration used: CodeRabbit UI
Review profile: CHILL
Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between bfbd603 and 7b15140.

📒 Files selected for processing (6)

• android/SherpaOnnxTts/app/src/main/java/com/k2fsa/sherpa/onnx/MainActivity.kt (3 hunks)
• android/SherpaOnnxTtsEngine/app/src/main/java/com/k2fsa/sherpa/onnx/tts/engine/TtsEngine.kt (3 hunks)
• scripts/apk/build-apk-tts-engine.sh.in (1 hunks)
• scripts/apk/build-apk-tts.sh.in (1 hunks)
• scripts/apk/generate-tts-apk-script.py (3 hunks)
• sherpa-onnx/csrc/piper-phonemize-lexicon.cc (2 hunks)

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