OpenBMB/VoxCPM · error · ValueError

target text must be a non-empty string

Error message

target text must be a non-empty string

What it means

_generate validates that the synthesis text is a non-empty, whitespace-stripped string before running inference. Empty strings, None, non-str types, or whitespace-only text all raise ValueError.

Source

Thrown at src/voxcpm/core.py:229

            cfg_value: Guidance scale for the generation model.
            inference_timesteps: Number of inference steps.
            min_len: Minimum audio length.
            max_len: Maximum token length during generation.
            normalize: Whether to run text normalization before generation.
            denoise: Whether to denoise the prompt/reference audio if a
                denoiser is available.
            retry_badcase: Whether to retry badcase.
            retry_badcase_max_times: Maximum number of times to retry badcase.
            retry_badcase_ratio_threshold: Threshold for audio-to-text ratio.
            streaming: Whether to return a generator of audio chunks.
            seed: Optional random seed for reproducibility.
        Returns:
            Generator of numpy.ndarray: 1D waveform array (float32) on CPU.
            Yields audio chunks for each generation step if ``streaming=True``,
            otherwise yields a single array containing the final audio.
        """
        if not isinstance(text, str) or not text.strip():
            raise ValueError("target text must be a non-empty string")

        if prompt_wav_path is not None:
            if not os.path.exists(prompt_wav_path):
                raise FileNotFoundError(f"prompt_wav_path does not exist: {prompt_wav_path}")

        if reference_wav_path is not None:
            if not os.path.exists(reference_wav_path):
                raise FileNotFoundError(f"reference_wav_path does not exist: {reference_wav_path}")

        if (prompt_wav_path is None) != (prompt_text is None):
            raise ValueError("prompt_wav_path and prompt_text must both be provided or both be None")

        is_v2 = isinstance(self.tts_model, VoxCPM2Model)
        if reference_wav_path is not None and not is_v2:
            raise ValueError("reference_wav_path is only supported with VoxCPM2 models")

        text = text.replace("\n", " ")
        text = re.sub(r"\s+", " ", text)

View on GitHub (pinned to f5a1c6a6b9)

Solutions

1. Skip empty/blank inputs upstream before calling generate
2. Coerce to stripped str and check truthiness first
3. Log and continue in batch loops instead of failing the whole run

Example fix

# before
audio = model.generate(text=user_input)
# after
if not isinstance(user_input, str) or not user_input.strip():
    raise ValueError("nothing to synthesize")
audio = model.generate(text=user_input)

if not isinstance(text, str) or not text.strip():
    raise ValueError("nothing to synthesize")

def is_synthesizable(text) -> bool:
    return isinstance(text, str) and bool(text.strip())

When it happens

Trigger: Calling generate('') , generate(None), generate(' '), or passing bytes/a list instead of str.

Common situations: Feeding pipeline output where a transcript field is empty, iterating over a file with blank lines, or frontend data arriving untyped.

Related errors

• Expected string input, got {type(text)}
• Retry on bad cases is not supported in streaming mode, setti
• Retry on bad cases is not supported in streaming mode, setti

AI-assisted analysis of OpenBMB/VoxCPM@f5a1c6a6b9 (2026-08-27). Data as JSON: /api/errors/35942fd1ffd6172f. Report an issue: GitHub.