chenhg5/cc-connect · error

pico2wave: produced empty audio file

Error message

pico2wave: produced empty audio file

What it means

PicoTTS.Synthesize (core/tts.go:650) runs the external pico2wave CLI to synthesize text into a WAV temp file, then reads it back. This error is returned when pico2wave exits successfully (exit code 0) but wrote a zero-byte WAV file, meaning no audio was actually produced. The library treats a silent/empty output as a synthesis failure rather than returning empty audio to the caller.

Source

Thrown at core/tts.go:650

		"--wave=" + tmpPath,
		text,
	}

	// Execute pico2wave command
	cmd := exec.CommandContext(ctx, p.Path, args...)
	output, err := cmd.CombinedOutput()
	if err != nil {
		return nil, "", fmt.Errorf("pico2wave: voice=%s text=%q: %w, output: %s", voice, text, err, string(output))
	}

	// Read the generated WAV file
	audioData, err := os.ReadFile(tmpPath)
	if err != nil {
		return nil, "", fmt.Errorf("pico2wave: read output file: %w", err)
	}

	if len(audioData) == 0 {
		return nil, "", fmt.Errorf("pico2wave: produced empty audio file")
	}

	return audioData, "wav", nil
}

// ──────────────────────────────────────────────────────────────
// EdgeTTS — Microsoft Edge TTS (free, high quality, requires network)
// ──────────────────────────────────────────────────────────────

// EdgeTTS implements TextToSpeech using Microsoft Edge's free TTS API.
// This uses the edge-tts CLI command under the hood.
type EdgeTTS struct {
	Path  string // path to edge-tts executable (empty = "edge-tts")
	Voice string // default voice (e.g. "zh-CN-XiaoxiaoNeural")
}

// NewEdgeTTS creates a new EdgeTTS instance.
func NewEdgeTTS(voice string) *EdgeTTS {

View on GitHub (pinned to 4000b2338a)

Solutions

  1. Check the text argument passed to Synthesize is non-empty and contains pronounceable characters before calling
  2. Verify pico2wave has the voice/language packs for the configured --lang (run `pico2wave --lang=en-US -w /tmp/t.wav 'test'` manually and inspect the file size)
  3. Reinstall/symlink the missing libttspico language data files (e.g. /usr/share/pico/lang/*)
  4. Fall back to another TTS backend (espeak, edge-tts) when this error occurs

Example fix

// before
audio, format, err := tts.Synthesize(ctx, strings.TrimSpace(userText), opts)
// after
text := strings.TrimSpace(userText)
if text == "" {
    return fmt.Errorf("cannot synthesize empty text")
}
audio, format, err := tts.Synthesize(ctx, text, opts)
Defensive patterns

Strategy: validation

Validate before calling

func canSynthesize(tts *core.PicoTTS, text string) error {
    if strings.TrimSpace(text) == "" {
        return errors.New("empty text for TTS")
    }
    return nil
}

Type guard

if len(audio) == 0 || (len(audio) > 44 && string(audio[:4]) != "RIFF") {
    // treat as failed synthesis, use fallback TTS
}

Try / catch

audio, format, err := pico.Synthesize(ctx, text, opts)
if err != nil {
    if strings.Contains(err.Error(), "produced empty audio file") {
        slog.Warn("pico2wave produced no audio, falling back to espeak")
        audio, format, err = espeak.Synthesize(ctx, text, opts)
    }
    if err != nil {
        return fmt.Errorf("tts: %w", err)
    }
}

Prevention

When it happens

Trigger: Calling PicoTTS.Synthesize (directly or via the TTS engine) when the pico2wave binary exits 0 but creates no WAV content — e.g. synthesizing empty or whitespace-only text, an unsupported --lang value that pico2wave silently ignores, text consisting only of characters pico cannot pronounce, or a pico2wave build missing the language voice packs writing nothing while still exiting 0.

Common situations: Developers hit this on minimal/container images where libttspico language data is partially installed, after passing an invalid voice like 'zh-CN' on a build with only en-US packs, or when downstream code (e.g. message preprocessing) trims the text to an empty string before synthesis.

Understand the failure class

Background: "empty response", "returned no data", "empty embeddings": what HTTP 200-with-empty-body errors mean across libraries — this error's family across 36 libraries.

Related errors

AI-assisted analysis of chenhg5/cc-connect@4000b2338a (2026-09-06). Data as JSON: /api/errors/c09f9e3f3cb4f54b. Report an issue: GitHub.