Python API

Load once

from inference import InflectTTS

tts = InflectTTS(model_dir=".", device="cpu")

model_dir must contain model.pth, config.json, the public frontend, and runtime/. device accepts a PyTorch device string such as cpu, cuda, or cuda:0. Loading validates the release architecture and raises FileNotFoundError for missing artifacts or RuntimeError for an incompatible checkpoint.

Keep one engine alive for repeated requests. Constructing an engine reloads the checkpoint and should not happen per utterance.

`synthesize`

sample_rate, waveform = tts.synthesize(
    "A compact model can still speak clearly.",
    speed=1.0,
    variation=0.667,
    seed=7,
)

Signature:

synthesize(text, *, speed=1.0, variation=0.667, seed=0)

Returns (sample_rate, waveform):

sample_rate: integer 24000, in samples per second.
waveform: one-dimensional, mono numpy.ndarray with float32 samples clipped to [-1.0, 1.0].

Validation:

empty or whitespace-only text raises ValueError;
speed must be in 0.5–2.0;
variation must be in 0.0–1.0;
seed is converted to an integer.

seed repeats the same stochastic sample on the same model/runtime stack. Cross-version or cross-device bit identity is not guaranteed.

`save`

output = tts.save(
    "This is written directly to disk.",
    "outputs/out.wav",
    seed=7,
)

save(text, output, **synthesis_options) creates parent directories, writes a mono 24 kHz PCM WAV, and returns the output Path.

Long text

Long input is normalized, split first at sentence punctuation and then at safe intra-sentence boundaries. Each chunk is generated independently with seed + chunk_index, edge-faded, and joined with punctuation-dependent silence. This bounds memory, but it is not one globally planned long-form prosody pass.

Concurrency

One InflectTTS instance mutates random-number state during synthesis. Serialize requests to one instance. For concurrent serving, use a worker pool with one engine per worker/device and enforce an application-level queue.

CLI

python inference.py \
  --model-dir . \
  --device cpu \
  --text "Inflect is running locally." \
  --output out.wav \
  --speed 1.0 \
  --variation 0.667 \
  --seed 7

Run python inference.py --help for the authoritative flag list.

Deliberate omissions

The v2 API does not expose speaker cloning, streaming state, SSML, native pitch control, or language switching. Pitch-shifting generated audio is post-processing and is not part of the model contract.