Can you give me a strategy for implementing TTS ca...
# ask-ai
b
Can you give me a strategy for implementing TTS caching for my livekit agent
t
Thanks for reaching out, Patrick. I'm an AI assistant and I'm here to help. Give me a moment while I research this topic.
To help you implement TTS caching for your LiveKit agent, a great approach is to create a wrapper around the TTS instance. This way, you can easily intercept synthesis requests and return cached audio whenever it's available. Here’s a simple overview to guide you: • Cache Key Design: Consider using a unique key that combines the input text, TTS model, voice settings, and audio format to keep things organized. • Cache Storage: You can store cached audio in memory, on disk, or even in a distributed store like Redis, depending on what fits your needs best. • Integration: The
before_tts_cb
hook is handy for preprocessing, or you might prefer creating a custom TTS wrapper to manage the caching logic smoothly. • Cache Invalidation: It’s important to have policies to invalidate outdated cache entries, whether based on configuration changes or a time-to-live (TTL) setting. If you'd like, I can provide a simple code example for a minimal caching wrapper using an in-memory dictionary. Just let me know! Sources: livekit-plugins/livekit-plugins-hume/livekit/plugins/hume/tts.py | chain-of-thought-tts/agent.py | Working with plugins | LiveKit Docs
b
That would be great thank you
t
Here’s a simple example of a minimal caching wrapper for TTS using an in-memory dictionary that I hope you'll find helpful:
Copy code
class CachingTTS(TTS):
    def __init__(self, tts: TTS):
        super().__init__(
            capabilities=tts.capabilities,
            sample_rate=tts.sample_rate,
            num_channels=tts.num_channels
        )
        self._tts = tts
        self._cache = {}

    def _generate_key(self, text: str, **kwargs) -> str:
        # Create a unique key based on text and TTS settings
        import hashlib
        key_data = f"{text}|{kwargs}"
        return hashlib.sha256(key_data.encode()).hexdigest()

    def synthesize(self, text: str, **kwargs):
        # Generate cache key
        key = self._generate_key(text, **kwargs)

        # Check if audio is already cached
        if key in self._cache:
            return self._cache[key]

        # If not cached, synthesize and store in cache
        audio = self._tts.synthesize(text, **kwargs)
        self._cache[key] = audio
        return audio
How it works: • The
_generate_key
method creates a unique hash for each TTS request based on the input text and settings. • The
synthesize
method checks the cache for existing audio before invoking the TTS engine. • Newly synthesized audio is stored in the cache for future use. Feel free to build on this by using a more robust caching backend like Redis or disk storage. If you have any questions or want to explore this further, just let me know—I’m here to help!