Kokoro int8 Model for ONNX

Kokoro 82M export to ONNX as int8. This model is from this GitHub repo. The voices file is from this repository.

Usage with txtai

txtai has a built in Text to Speech (TTS) pipeline that makes using this model easy.

Note: This requires txtai >= 8.3.0. Install from GitHub until that release.

import soundfile as sf

from txtai.pipeline import TextToSpeech

# Build pipeline
tts = TextToSpeech("NeuML/kokoro-int8-onnx")

# Generate speech
speech, rate = tts("Say something here")

# Write to file
sf.write("out.wav", speech, rate)

Usage with ONNX

This model can also be run directly with ONNX provided the input text is tokenized. Tokenization can be done with ttstokenizer. ttstokenizer is a permissively licensed library with no external dependencies (such as espeak).

Note that the txtai pipeline has additional functionality such as batching large inputs together that would need to be duplicated with this method.

import json
import numpy as np
import onnxruntime
import soundfile as sf

from ttstokenizer import IPATokenizer

# This example assumes the files have been downloaded locally
with open("kokoro-int8-onnx/voices.json", "r", encoding="utf-8") as f:
    voices = json.load(f)

# Create model
model = onnxruntime.InferenceSession(
    "kokoro-int8-onnx/model.onnx",
    providers=["CPUExecutionProvider"]
)

# Create tokenizer
tokenizer = IPATokenizer()

# Tokenize inputs
inputs = tokenizer("Say something here")

# Get speaker array
speaker = np.array(voices["af"], dtype=np.float32)

# Generate speech
outputs = model.run(None, {
    "tokens": [[0, *inputs, 0]],
    "style": speaker[len(inputs)],
    "speed": np.ones(1, dtype=np.float32) * 1.0
})

# Write to file
sf.write("out.wav", outputs[0], 24000)

Speaker reference

The Kokoro model has a number of built-in speakers.

When using this model, set a speaker id from the reference table below.

The following shows an example on how to set a speaker id when using txtai

speech, rate = tts("Say something here", speaker="af_sky")