Synthesizing speech
Dengjen synthesizes speech from a Piper voice. Download a
voice’s .onnx model and matching .onnx.json config from the
Piper voices repository and keep both files
together, e.g. voices/en_US-lessac-medium.onnx and voices/en_US-lessac-medium.onnx.json.
A voice doesn’t have to come from the official Piper voices repository — any VITS-family ONNX
export using the same 3/4-input tensor convention (phoneme ids, lengths, scales, optional
speaker id) can be loaded by writing a matching .onnx.json manifest with
"model_type": "vits". The minimal required fields are audio (sample rate), inference
(noise_scale/length_scale/noise_w), and phoneme_id_map (the symbol vocabulary);
phoneme_type selects the phonemizer (espeak is the default if omitted, and needs an
espeak.voice entry — text, hebrew, and pinyin don’t).
A MeloTTS voice — its own VITS-derived ONNX export, with
a tones tensor alongside phone ids — is loaded with "model_type": "melotts". The required
fields are audio (sample rate), inference
(noise_scale/length_scale/noise_scale_w), phone_id_map and tone_id_map (the phone and
tone symbol vocabularies), and model_path; phonemizer selects the phonemization backend and
must be one of {"type": "espeak", "voice": "<espeak-ng voice name>"} (covers English, Spanish,
French, Japanese, Korean) or {"type": "pinyin", "model_dir": "<g2pW model directory>"}
(Chinese, with real tone extraction — requires building with the pinyin feature).
CLI
Synthesize text from a file to a WAV file, using the dengjen-cli frontend:
cargo run --release -p dengjen-tts-cli -- voices/en_US-lessac-medium.onnx.json \
-f input.txt \
-o output.wavOr send a single request as JSON on stdin and capture the WAV bytes written to stdout:
echo '{"text": "Hello world"}' | cargo run --release -p dengjen-tts-cli -- voices/en_US-lessac-medium.onnx.json > output.wavRun dengjen --help (or cargo run --release -p dengjen-tts-cli — --help) for the full list
of options, including synthesis mode, speaker id, rate/pitch/volume, and streaming chunk size.
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