babysor/MockingBird · error · ValueError

No segments to mix.

Error message

No segments to mix.

What it means

ValueError raised by mix_all when the list of input segment paths is empty. The final timeline mix needs at least one rendered segment to build an ffmpeg amix filter graph.

Solutions

1. Fail loudly on the first per-cue synthesis error instead of continuing with an empty list
2. Check why zero segments were produced (API failures, missing voices) before the mix step
3. Add a sanity check: if len(segments) != len(cues): warn

Example fix

# before
mix_all(segments, out, total_ms)
# after
if not segments:
    raise RuntimeError("all cue syntheses failed; see logs above")
mix_all(segments, out, total_ms)

assert segments, 'no segments produced; check per-cue logs'

When it happens

Trigger: All per-cue TTS segments failed or were filtered out before mixing, or parse_srt produced cues but synthesis yielded zero output files.

Common situations: A loop swallows per-cue synthesis errors and continues, leaving inputs empty; or a voice-map misconfiguration maps every cue to a skipped backend.

Related errors

• ffmpeg failed: \n
• ffprobe failed on
• Both increase only and decrease only are set
• Cue : either voice_id or reference_audio required.
• duration must be in range (0, 36] seconds

AI-assisted analysis of babysor/MockingBird@28dc5e14f1 (2026-08-27). Data as JSON: /api/errors/59d4a8304fe633dd. Report an issue: GitHub.

Appendix: source

Thrown at skills/speak/scripts/render_timeline.py:184

    filters.append(f"atempo={r:.6f}")

    _run_ff([
        "ffmpeg", "-y", "-i", str(inp),
        "-af", ",".join(filters),
        "-t", f"{target_ms / 1000.0:.3f}", str(outp),
    ])


def delay_segment(inp: Path, outp: Path, start_ms: int) -> None:
    _run_ff([
        "ffmpeg", "-y", "-i", str(inp),
        "-af", f"adelay={start_ms}:all=1", str(outp),
    ])


def mix_all(inputs: List[Path], outp: Path, total_ms: int) -> None:
    if not inputs:
        raise ValueError("No segments to mix.")
    cmd = ["ffmpeg", "-y"]
    for p in inputs:
        cmd += ["-i", str(p)]
    cmd += [
        "-filter_complex",
        f"amix=inputs={len(inputs)}:duration=longest:dropout_transition=0",
        "-t", f"{total_ms / 1000.0:.3f}", str(outp),
    ]
    _run_ff(cmd)


# ── Noiz backend ─────────────────────────────────────────────────────


def _noiz_emotion_enhance(
    base_url: str, api_key: str, text: str, timeout: int
) -> str:
    import requests  # noqa: delayed import so kokoro path doesn't need requests

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