* fix(dub): the speaker-count hint is honored on every diarization path + clone-purity guard
The dub "Speakers" count reached _diarize() and then died on 3 of its 4
branches, so setting it changed nothing, speakers blended, and auto-clones
were cut from mixed-speaker audio ("made up" voices):
- FunASR inline-turns shortcut returned before the hint was ever consulted
→ now an explicit num_speakers routes the job through pyannote (the one
engine that honors an exact count); turns stay the fast path only when no
hint is set, and remain the fallback (with an honest "hint ignored"
warning) when pyannote can't load or crashes mid-run.
- pyannote-unavailable fallback used a hardcoded 2-speaker silence-gap
heuristic → assign_speakers_heuristic now takes num_speakers and cycles N
labels on gap boundaries (1 → single speaker; None → legacy alternation),
and the existing diarization warning says the hint is only approximately
honored.
- pyannote-crash fallback dropped the hint the same way → same treatment.
No branch drops the hint silently anymore: every degraded path extends the
existing `warning` SSE payload (detail + a machine-readable speaker_hint
field) that the frontend already renders.
Parity + purity:
- POST /dub/transcribe/{job_id} (the CLI's endpoint) gains the same clamped
num_speakers query param, forwarded to pyannote and the heuristic; the
omnivoice-dub CLI gains --speakers N.
- Clone-purity guard: _pick_reference_slices rejects sub-1.5s slices, prefers
slices not temporally adjacent (<0.3s) to another speaker's turn (scoring
preference, not a hard filter), and extract_speaker_clones skips extraction
entirely when labels came from the heuristic (labels_source kwarg threaded
from _diarize; missing kwarg keeps the old behavior) — with a user-facing
warning pointing at Settings → Models → pyannote.
Tests: fail-before/pass-after coverage in tests/test_speaker_hint.py (all
four _diarize branches driven through the real SSE stream), clone-purity
guards in tests/test_speaker_clone_purity.py, heuristic hint semantics in
tests/test_segmentation.py.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
* docs(changelog): add the speaker-hint + clone-purity fix under [Unreleased] (#952)
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
---------
Co-authored-by: mergetest <test@local>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
