* fix(engines): dub and batch TTS honor the active-engine selection — with a real capability gate, not a silent OmniVoice fallback
Dub generation and batch TTS hardcoded services.model_manager.get_model()
(OmniVoice) regardless of the engine picked in Settings → Engines. A user
selecting VoxCPM2 (or any other engine) still got OmniVoice output with no
error — the silent fallback IS the bug class, not just the one report.
Root-caused and fixed for the whole class:
- New `TTSBackend.supports_cloning` capability flag (default True) marks
engines that can only offer fixed preset voices — kittentts,
supertonic3, sherpa-onnx set it False. MLXAudioBackend exposes it as an
instance property (Kokoro doesn't clone, CSM does) since the adapter
multiplexes multiple models with different capabilities.
- `cloning_capable_engine_ids()` and a shared `resolve_generation_backend()`
helper in services/tts_backend.py centralize engine resolution
(id → is_available() → routing gate → optional cloning gate), mirroring
generation.py's /generate resolution instead of inventing a third
parallel mechanism. Both routers now standardize on the existing
get_active_tts_backend() cache (unload-on-switch already handled).
- dub_generate.py's two TTS-generate call sites (main run + OOM retry) and
the /dub/preview-segment route resolve once, up front, with
require_cloning=True — dub's ref_audio is populated for essentially
every real job, so an engine that can't clone fails the whole job with
one actionable message instead of mis-cloning per segment.
- batch.py resolves once per job, require_cloning only when voice_id is
pinned — an unpinned batch job runs fine on any engine.
- Applied the three pre-existing TODO(#312) comments: mastering now skips
via `applies_own_mastering` for both pipelines, matching generation.py.
Regression tests cover the capability-id list, the fail-fast gate (proving
no OmniVoice fallback), the success path on a selected non-OmniVoice
engine, batch's pinned-vs-unpinned voice_id behavior, and the mastering
skip for both pipelines. Three existing dub tests that mocked get_model()
directly were updated to mock the new resolver instead.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
* fix(engines): exclude model-dependent adapters from cloning_capable_engine_ids()
getattr(cls, "supports_cloning", True) at the CLASS level returns a
property descriptor object (always truthy) when the flag is an instance
@property, not a plain attribute — MLXAudioBackend uses exactly this
pattern because its cloning capability depends on which of its 7+ curated
models is loaded (only CSM clones; Kokoro etc. don't). Without this fix,
the dub/batch capability-gate error message would always recommend
'switch to mlx-audio' even when the user's configured MLX model can't
clone, sending them in a circle back to the same error.
isinstance(value, bool) distinguishes a resolved boolean from a
descriptor object, so mlx-audio is excluded from the suggestion list
until its actual per-instance capability can be checked (already handled
correctly by resolve_generation_backend()'s per-call instance check).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
* docs(changelog): engine-aware dub/batch entry (#987)
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
---------
Co-authored-by: mergetest <test@local>
Co-authored-by: Claude Sonnet 5 <noreply@anthropic.com>
