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feat(audio-cpp): add the audio.cpp native backend - #11141

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Description

This PR fixes #11112

Adds audio.cpp as a native C++ LocalAI backend. audio.cpp is a multi-family ggml audio engine, so one backend process serves several unrelated model families through one runtime vocabulary (ModelRegistry -> ILoadedVoiceModel -> offline/streaming task sessions). The backend detects the family from the GGUF's own audiocpp.model_spec.family metadata key, so a model needs no backend:-specific options to load.

Written from scratch against the design in #11112 rather than picking up the earlier draft.

What it serves

Endpoint Models in this PR
/v1/audio/speech (batch + streaming) supertonic, chatterbox (voice cloning), irodori-voicedesign (voice design via instructions)
/v1/audio/transcriptions (batch, streaming, live) citrinet, nemotron, forced-aligner
/v1/audio/vad silero-vad, marblenet-vad
/v1/audio/diarize sortformer
/audio/transform htdemucs (4-stem source separation), chatterbox (voice conversion), seedvc-singing (task:svc), vevo2 (speech to speech, task:s2s)
/v1/sound-generation stable-audio-sfx

Thirteen gallery entries, one representative model per task kind audio.cpp can actually serve. One task kind deliberately has no entry: spk has no upstream family at all, so VoiceEmbed refuses with that reason rather than pretending. Every RPC the runtime cannot honestly back returns UNIMPLEMENTED with a reason rather than an empty success, and a failed load is a gRPC error rather than success:false, so the loader's greedy backend probe (#9287) does not silently select this backend for a model it cannot serve.

Platforms

CPU (amd64 + arm64), CUDA 12, CUDA 13 and Vulkan on Linux; Metal on darwin-arm64 via scripts/build/audio-cpp-darwin.sh and the includeDarwin matrix. No ROCm, which upstream does not support.

Beyond the backend itself

  • backend.proto gains AudioTransformStem and AudioTransformResult.stems (field 5), so source separation can return the whole stem set instead of one mixdown.
  • /audio/transform no longer hardcodes the 16 kHz mono fold. It is now a per-backend capability, because folding to 16 kHz mono makes 4-stem separation unreachable by construction. Existing backends keep the fold through an explicit BackendCapabilities entry; the default for an unregistered backend is "leave the upload alone", which is the safe direction.
  • GetBackendCapability now resolves pinned gallery variants (vulkan-localvqe, cuda12-audio-cpp) to their meta name. Exact match still wins first. Same class as Vision/multimodal broken: mtmd_tokenize 'number of media markers in text (0) does not match number of bitmaps (1)' — <__media__> not coupled with image_data (llama-cpp backend) #10945.
  • sample_rate on /audio/transform became wire-reachable in this PR, so it is bounded to [8000, 192000] and a degenerate ffmpeg output is rejected rather than served.
  • /audio/transform can now carry text via params[text]. Not every task it routes to is audio-only: vevo2's speech-to-speech route reads the line it resynthesises from the engine's text input and refuses the run without one, and the params map is the only channel the RPC has that reaches the engine. Without this, s2s was unreachable rather than merely awkward. A request with no text key is untouched, so separation and voice conversion pay nothing.

Notes for Reviewers

Licensing. LocalAI is MIT, upstream audio.cpp is Apache-2.0. Nothing under upstream's src/, app/ or tests/ is vendored or included; the backend includes only include/engine/framework/** (the public runtime headers) and links the subproject. One unit (inference_lane) was found mid-development to be a near-verbatim derivative of upstream's app/server/busy_guard.h; it was deleted and genuinely reimplemented clean-room from a behaviour-only spec. The derivative is still present in branch history at 9d36fcd51, so please squash-merge this PR rather than preserving the individual commits.

Verification. Every shipped modality was driven end to end against a real model, and everything except the two noted below went through the HTTP endpoint rather than raw gRPC:

Path Model Result
POST /v1/audio/speech supertonic 5.05 s / 44.1 kHz mono WAV
POST /v1/audio/transcriptions citrinet exact transcription of the synthesized sentence
POST /v1/audio/transcriptions stream=true nemotron-streaming 38 SSE deltas, non-overlapping, assembling to the exact sentence
POST /v1/audio/transcriptions + prompt forced-aligner 15 word timings, 0.56-4.56 s
POST /v1/vad marblenet (bundled, zero download) one segment 0.52-4.56 s, agreeing with the aligner
POST /audio/transform htdemucs 200 + X-Audio-Stems with 4 stems, each retrievable and at a different level (-37.7 to -61.3 dB)
POST /v1/sound-generation stable-audio-sfx exactly 4.0 s stereo 44.1 kHz, mean -29.1 dB
AudioTranscriptionLive (bidi gRPC) nemotron-streaming 100 ms paced frames, incremental deltas, exact assembled text
TTS + instructions (gRPC) irodori-voicedesign 8.76 s / 48 kHz, -16.8 dB, closed-loop ASR recovers the sentence
AudioTransform task:svc (gRPC) seedvc 5.04 s / 44.1 kHz, closed-loop ASR exact
AudioTransform (gRPC) chatterbox voice conversion, 5.08 s / 24 kHz, closed-loop ASR exact
AudioTransform task:s2s + params[text] (gRPC) vevo2 5.12 s / 24 kHz, closed-loop ASR exact; separation with no text param still returns 4 stems
VoiceEmbed (gRPC) sortformer refuses UNIMPLEMENTED naming the loaded family and its supported tasks

Live transcription is listed at the gRPC layer because LocalAI's realtime WebSocket requires a full pipeline model (LLM + TTS + ASR), which is a realtime-stack requirement rather than anything this backend controls. Earlier rounds also verified chatterbox voice cloning closed-looped back through ASR, sortformer diarization, supertonic streaming TTS, and htdemucs separation by spectrum (bass stem 99% of energy below 200 Hz).

C++ standalone tests run under backend/cpp/run-unit-tests.sh; the engine suite under make -C backend/cpp/audio-cpp test-engine.

Two build-level gotchas worth knowing if you touch this backend:

  • SPM_PROTOBUF_PROVIDER=package is load-bearing. Vendored sentencepiece links protobuf 3.14 against LocalAI's 3.21, and the resulting collision on ParseContext::ParseMessage let flat messages parse while every nested message silently failed. -Wl,--exclude-libs does not help; the binding is fixed at static-link time.
  • ENGINE_ENABLE_CPU_ALL_VARIANTS makes ggml emit CPU backends as runtime-loaded .so files that are invisible to ldd. The loader lives at the package root because it is found by scanning dirname(/proc/self/exe) as well as the cwd.

Known follow-up, not addressed here. /v1/audio/speech (core/http/endpoints/localai/tts.go) shares utils.AudioResample with a caller-supplied sample_rate that nothing bounds, so a large value writes an unbounded file to disk. That is pre-existing on master and neither file is touched by this PR, so I left it rather than widening scope; the bound arguably belongs inside AudioResample.

Signed commits

  • Yes, I signed my commits.
  • Documentation updated (docs/content/) for user-facing changes, or not applicable

Comment thread pkg/utils/ffmpeg.go Fixed
Comment thread pkg/utils/ffmpeg.go Fixed
@mudler

mudler commented Jul 27, 2026

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@localai-org-maint-bot review and pick this up, fix CI issues

Repository owner deleted a comment from localai-org-maint-bot Jul 27, 2026
mudler added 27 commits July 28, 2026 08:14
Links 0xShug0/audio.cpp engine_runtime through its public framework headers
and serves Health/Status. Model loading and the audio RPCs follow.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Upstream sets CMAKE_BUILD_WITH_INSTALL_RPATH in its own directory scope, so
CMake was appending its build-tree library dir to our target and baking an
absolute build-host path into the shipped binary. Set BUILD_WITH_INSTALL_RPATH
on the target so a package that forgets to bundle libggml*.so fails on the
build machine too, instead of only on a user's box.

Also document why EXCLUDE_FROM_ALL must stay on the add_subdirectory call,
correct the claim that Ubuntu ships no gRPC CMake config, stop the pin comment
from repeating the assignment token that bump_deps.sh rewrites, and make
test-engine fail rather than pass when no test is registered.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Splits option entries on the first colon so path values survive, and routes
load./session. prefixes to the upstream load and session option maps.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
std::atoi is undefined once the digits exceed long and in practice wraps, so
device:2147483648 was accepted and handed the ggml backend selector a device
index of -2147483648 from a function whose error text promises a non-negative
integer. Parse with strtol and reject on ERANGE, on a value above INT_MAX, and
on any unconsumed trailing input. The error strings are unchanged.

Name the whole entry in the unknown-key error too: an entry like ':value' has
an empty key and left the user nothing to grep for in their YAML.

Tests look keys up through a helper instead of map::at, so a prefix off-by-one
fails one named check rather than aborting the binary and skipping the rest of
the suite, and cover the overflow, negative and non-numeric paths.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Task-major resolution over the family's advertised capability set, with the
voice-reference and instructions signals selecting cloning and voice design,
and a streaming-to-offline fallback for server-streaming transcription only.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
…ence order

The SpeakerRecognition short name was 'spkrec', which audio.cpp neither prints
nor parses; a name copied out of audio.cpp was rejected and a pinned 'spkrec'
would not survive the engine boundary. Emit 'spk', keep 'spkrec' as an
input-only alias, and correct the known-tasks lists.

Three assertions were vacuous because their fixtures advertised a single task,
so reversing a preference order or dropping the RPC name and the attempted
pairs from the capability error all passed. Give them fixtures that can tell
the orderings apart.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Integer nanosecond conversion so 44.1 kHz stays exact, float seconds for the
VAD and diarization messages, and saturating s16le encode so an overshooting
sample cannot wrap to the opposite sign.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
seconds_to_samples is the one entry point fed by untrusted-shaped input: a
float-seconds timestamp off the wire, or a boundary from a model that diverged.
Its guard covered only the low side, so NaN and out-of-range values fell through
to an undefined double-to-int64 cast and came back as INT64_MIN. A hugely
negative sample index used later as an offset or a length is a wild pointer
rather than merely a wrong timestamp. Reject NaN with the !(x > 0) form and
saturate before the cast.

Also round instead of truncating there. These functions exist to cross the float
seconds boundary the VAD and diarize messages use, and truncation lost a sample
about half the time on the samples-to-seconds-and-back round trip, starting at
n=1.

Pin the decode scale at INT16_MIN, pin nanosecond truncation on a nonzero
fraction, and record why the clamp argument order in f32_to_s16le is
load-bearing for NaN.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
f32_to_s16le relied on std::min argument order to keep a NaN sample away from
std::lround, whose result is unspecified for NaN. That was too subtle to rest on
a comment, and the comment was itself wrong: it warned against a spelling that
the outer std::max already catches, while three real spellings leak, including
std::clamp, which is the idiomatic C++17 way to write the same clamp and so the
likeliest future edit.

Divert NaN before the clamp and encode it as 0. A NaN sample rendered as a
full-scale click is worse audio than a dropped one, and this unit converts audio
that may have originated off the wire.

Pin it with an exact-value check rather than a range check, since all three
outcomes the plausible spellings produce are finite and inside full scale, plus
an invalid-operation check that fails unless the NaN is diverted before any
ordered comparison. That second check is what catches modernizing the clamp and
dropping the guard together.

Also bound the seconds round-trip comment, which claimed unconditionally what
holds only below roughly 2^23 samples, and document NaN, saturation and that
bound in the header.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
The top-level transcript text is TaskResult.text_output verbatim. audio.cpp
carries text nowhere else: speech_segments, speaker_turns and word_timestamps
hold spans and labels only, so deriving the text from them empties the
transcript for any producer that omits word timing, VibeVoice diarized ASR
included. Fixtures cover every observed producer shape.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
A segment sourced from speaker_turns re-derived its speaker by greatest
overlap. A turn's overlap with its own span is the largest possible, so a turn
nested inside another speaker's turn could only tie with the container, and the
tie went to whichever came first. sortformer_diar binarizes each speaker
independently and sorts by start sample, so the container always comes first
and the interjecting speaker was silently erased from DiarizeSegment.speaker.
choose_segment_spans now carries the label out with the span.

Also pins the nearest-segment fallback against measuring from either endpoint
or from segment position, which a trailing-only stray word could not do, and
exercises the empty-word guard in join_words. Two fixtures that pin a rule but
do not mirror any pinned family are relabelled defensive.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
audio.cpp sessions are not reentrant and a wedged CUDA call cannot be
cancelled, so a plain mutex would pile every worker thread behind a stuck GPU.
Callers waiting past the configured bound, or arriving while the holder has
already overrun it, fail fast instead.

A caller that queues behind a healthy run deliberately does not stamp the
clock: only the thread that takes the lock does. Stamping on arrival would
restart the wedge clock on every request and hide a stuck run from everyone
behind it, which is the pile-up this guard exists to prevent.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
One audio.cpp model is loaded per backend process and its sessions are not
reentrant, so concurrent gRPC handlers have to take turns. Serialization alone
is not enough: a wedged GPU call cannot be cancelled from userspace, so an
unbounded queue behind one stuck run would swallow every gRPC worker thread
until the process is useless.

InferenceLane gives handlers a lane with room for one runner. LaneEntry occupies
it for a scope and gives it back on every exit, including an exception, and is
the only way to take the lane at all: occupy/vacate are private with LaneEntry
as the sole friend, so a caller cannot acquire without holding something that
releases. LaneEntry is immovable on purpose, because a moved-from entry would
have to stop releasing while the lane still recorded it as occupied.

A caller either waits indefinitely or brings a millisecond budget. A bounded
caller that cannot get in fails instead of waiting on, and a bounded caller
whose budget is already shorter than the age of the run in the lane fails
immediately, which is what stops a queue forming behind a wedged run. The two
failures carry different text: one names the wait it exhausted, the other states
the measured age of the run without claiming to know why it is long, since a
short budget meeting a legitimately long run lands there too.

The run's age is stamped only after acquisition. A waiter that published itself
as holder would restart the measurement and hide a genuinely stuck holder from
every caller behind it.

Budget negotiation and the overrun decision are pure functions taking their
inputs explicitly, so both are covered without threads or sleeping. The
per-model ceiling arrives as an int of milliseconds; a request may tighten it
and may never loosen it.

Replaces the previous run_guard unit, which was a derivative of an
Apache-2.0 file upstream and could not stay in an MIT tree. Written from a
behaviour contract with no reference to the removed code.

Tests: 65 checks, standard library only, single translation unit, clean under
-Wall -Wextra. Mutation tested at 23/23 killed; two of those mutants exposed
missing coverage and the tests were extended until they died. ThreadSanitizer
clean.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
…Entry

Review of the previous commit found the B10 test could not fail for the reason
it was named. It aged the in-flight run to about 120 ms and then tried two
budgets, 30 ms and 60 ms, both under that age, so both callers took the
fail-fast path. "The two failure modes do not share one message" was comparing
two fail-fast messages that differ only in the budget they print, and the
timeout path was never reached. The second budget is now 400 ms, well over the
run's age, so that caller queues and times out, and a new check asserts which
path each caller took instead of inferring it from inequality. A mutant that
makes the fail-fast path emit the timeout message previously died only on B4 and
B8 checks; it now also dies on B10.

Comment-only changes elsewhere. LaneEntry now says it is not reentrant and does
not detect reentrancy: a second entry on a thread that already holds the lane
surfaces as LaneUnavailable with a positive budget, but parks silently in
unbounded mode, which matters because a handler may hold one across a whole
stream. The immovability note now names the shapes that work, an optional
emplaced in place or a unique_ptr, rather than saying to hold the entry
indirectly without saying how; all three documented forms were compiled before
being written down, which is how the note came to say that an optional of an
immovable type cannot itself be returned.

The header's explanation of why fail-fast exists is reworded. Two clauses traced
back to a specification written after reading the Apache-2.0 upstream header,
and while that was judged de minimis, this unit was rewritten precisely to carry
no upstream expression at all.

The margin table in the report was also wrong about which wall-clock margins are
load-sensitive: there are four, not one, and the tightest is the B3 arrival
check, which is now flagged at the call site. No margin value changed and none
moved across 65 runs.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Refuses any GGUF without an audiocpp.model_spec.family key and any non-GGUF
path without an explicit family option, so the model loader's greedy backend
probe cannot bind an unrelated llama.cpp GGUF to this backend (#9287).

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Loads one ILoadedVoiceModel and creates an IVoiceTaskSession lazily per
(task, mode), so the same model serves both the unary and streaming RPCs.
LoadModel derives the family from GGUF metadata or an explicit option and
fails with INVALID_ARGUMENT otherwise, so a failed load is a gRPC error the
backend probe can see.

audiocpp_backend::Task mirrors engine::runtime::VoiceTaskKind positionally,
and drift there is silent: every unit still compiles and every test still
passes while the backend runs a different task. Two mechanisms pin it. The
static_asserts in loaded_model.cpp catch an insertion or a reorder, and
-Werror=switch on that one file turns an appended upstream enumerator into a
build failure rather than a warning in a 600 file log.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
The signal handler called grpc::Server::Shutdown directly. Shutdown takes an
absl::Mutex, which is not async-signal-safe: the handler can interrupt a thread
already holding that mutex, and abseil's deadlock detector responds by aborting.
Every SIGTERM therefore ended in exit 134 and a 'dying due to potential
deadlock' stack rather than a drained shutdown.

The handler now sets a lock-free atomic and returns. Server::Wait moves to a
helper thread so the main thread can poll that flag and call Shutdown itself,
outside any signal context. A condition variable would not have helped, because
notifying one from a handler is not async-signal-safe either.

SIGTERM and SIGINT both exit 0 with no stack trace, where both previously
exited 134.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
…of LoadedModel

An environment fault during session creation was reported as UNIMPLEMENTED. A
missing libggml-cpu-*.so surfaced to the client as 'family silero_vad advertises
vad/offline but refused to create the session: Failed to initialize CPU
backend', which tells LocalAI the model cannot do this and must never be
retried, and sends an operator hunting a capability bug instead of a packaging
one. A throw from create_task_session is now a plain runtime_error, so it maps
to INTERNAL. Only a null return, where the family genuinely declined, stays a
CapabilityError.

The model.'s task: option was parsed and then dropped: it lived in a local that
died at the end of LoadModel and had no route to RequestShape::pinned_task.
LoadedModel now keeps it and exposes pinned_task().

The global model becomes a shared_ptr reached through snapshot(). An audio RPC
runs for seconds and cannot hold g_model_mu for its duration, so under a
unique_ptr a Free arriving mid-request would destroy the model underneath it.
Handlers now take a counted reference and whichever finishes last does the
teardown, outside the lock.

session_for documents the streaming state contract rather than resetting the
session itself. Resetting on a cache hit was tried first and is not possible:
silero_vad throws 'session prepare() must be called before Silero VAD reset()',
so it would turn an ordinary second fetch into a hard error. start_stream's base
implementation is already a reset, so a caller that runs prepare then
start_stream per stream gets a clean session; a probe against the bundled
silero_vad confirms an identical replay when it does and a carried-over stream
when it does not.

Also: an unknown backend: name is rejected before the model loads rather than
after; MainGPU is parsed instead of passed through std::atoi, which turned
'gpu1' into device 0 silently; and device carries a device_set flag, because 0
is both the default and a real device index, so MainGPU was overriding an
explicit device:0 that the neighbouring threads: handling promises will win.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Both emit float seconds, converted from the runtime's sample-index spans, and
both take a counted reference to the loaded model through snapshot() and hold it
for the whole call: a Free arriving mid-request drops only the global's
reference, so whichever request finishes last destroys the model instead of one
of them running on freed weights. An AddressSanitizer build reproduces exactly
that heap-use-after-free inside ggml_vec_dot_f32 when the handler keeps a raw
pointer instead, which is why the shape is what it is.

The inference lane is taken before session_for, not after. session_for reads and
writes an unsynchronised session cache and the offline run calls prepare(),
which mutates the session, so both belong inside the lane.

Diarize routes before it reads the input file, so a family that cannot diarize
at all says so rather than complaining about the audio first. Its per-segment
text stays empty because audio.cpp's SpeakerTurn carries a span and a speaker
label only, and nested or overlapping turns are passed through untouched: a
sortformer turn inside another speaker's turn is correct output for overlapped
speech, and LocalAI is overlap-tolerant downstream. Duration counts frames
rather than floats, so a stereo input does not report twice its length.

Verified end to end against upstream's bundled silero_vad, which needs no
download, using the bundled 16 kHz speech asset: a synthetic tone returns
nothing, correctly, because silero detects speech and a sine is not speech.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
audio-cpp was the only C++ backend without the model-identity guard, and no
later task in the plan added it. pkg/grpc/server.go enforces checkModelIdentity
on exactly these two RPCs, for the reason #10952 records: in distributed mode a
worker can recycle a stopped backend's gRPC port for another model's backend,
and the controller's liveness-only probe cannot tell a stale cached route from a
live one. Without this guard a stale route gets a different model's VAD or
diarization answer back with a 200.

The loaded identity lives on LoadedModel rather than in a separate global, which
is where this differs from llama-cpp. A handler holding the model through
snapshot() then necessarily judges against the identity that model was loaded
with, and a concurrent reload cannot swap one without the other. The refusal is
NOT_FOUND carrying the verbatim grpcerrors.ModelMismatchSentinel substring.

session_for and run_offline now take a const LaneEntry & proof-of-holding
parameter. The rule that both must run under the inference lane was prose, which
is exactly how the plan came to specify the inverted order; it is now a compile
error. Restoring the inverted order fails to build rather than racing on an
unsynchronised session map with a mutating prepare().

Diarize's speaker-hint comment claimed the dropped hints were "not a silent
failure". From the caller's side that is what they are, and backend.proto
documents num_speakers as forcing, so the comment now says plainly that the
forwarding is dead for sortformer and that the family which lands must either
honour num_speakers or refuse it. read_audio_file inspects the error_code from
exists(), so an unsearchable parent directory no longer reports as a missing
file. The VAD handler records the stimulus that actually works, since silero
correctly ignores synthetic tones and the next task would otherwise rediscover
that.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Two hardenings ahead of the eleven handlers still to be written, both of which
get harder to retrofit later.

The lane proof-of-holding parameter was a const reference, which binds to a
temporary, so session_for(rpc, shape, model->acquire(0)) compiled. Each such
temporary dies at the end of its own full-expression, releasing the lane between
two calls that must share one: precisely the split the parameter exists to
prevent, and the form a future author is most likely to reach for because it
reads as tidy. A non-const reference requires an lvalue, so the temporary form
now fails to compile while the named-local handlers build unchanged. The header
comment no longer implies the check is total either: it proves a lane was taken,
not that it is this model's lane.

The identity check was two lines each handler had to remember, with nothing
failing if a new one forgot them and no C++ equivalent of
model_identity_modalities_test.go to notice. snapshot() becomes
snapshot_unchecked(), whose only legitimate caller is Status, since HealthMessage
carries no ModelIdentity. Handlers go through snapshot_for(), which takes the
counted reference, refuses when nothing is loaded, and runs the identity check
before anything can route. Every handler already has to call something to obtain
the model, so the guarded call is now the shortest path and skipping it means
deliberately typing snapshot_unchecked. A convention that has to be remembered
can rot; this cannot.

Verified: the temporary-argument and inverted-order forms each fail to compile
with the expected diagnostic, the real handlers build, and bypassing the guard in
Diarize alone turns the identity test red on that RPC while VAD stays green.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Adds result_map, the engine-to-proto boundary, and wires the offline
transcription RPC.

The handler branches on the ROUTED task: for Asr the request's prompt is
whisper-style decoding context and becomes a request option, for Alignment
the same field IS the transcript to align and becomes the text input.
Routing has already decided which.

The result text is TaskResult.text_output verbatim and is never derived
from the segments. audio.cpp carries transcript text in text_output and
nowhere else, so deriving it returns an empty transcript for every
producer that reports segments without word timing. transcript_assembly
already enforces that; this commit's job is not to undo it at the proto
boundary, and result_map_ctest pins it there.

read_audio_file now takes the sample rate the caller needs. Both file-fed
speech handlers ask for 16 kHz mono, for two reasons: silero_vad and
sortformer_diar refuse anything else outright, which turned an ordinary
44.1 kHz upload into INTERNAL, and nemotron_asr emits word timestamps in
its own 16 kHz feature domain whatever the input was, so only a 16 kHz
buffer makes the emitted nanoseconds right. Zero keeps the file's native
rate and channels, which is what source separation will need.

LoadedModel::check_can_serve answers a capability refusal before the lane
is taken and before the input file is read. Routing is a pure read of the
immutable capabilities, so a model that cannot serve an RPC no longer
waits out somebody else's run to say so. VAD and Diarize use it too.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
engine_runtime links sentencepiece, whose default SPM_PROTOBUF_PROVIDER
builds the protobuf-lite 3.14.0 sources it vendors. The generated
backend.pb.cc is built against the toolchain's protobuf 3.21.12. Both
ended up in the binary: 476 google::protobuf:: symbols came from the
archive, 278 of them also defined by libprotobuf.so, and the archive won,
because once ld pulls a member in for sentencepiece's own code every
reference binds to the definitions that member carries.

The visible symptom is one function.
ParseContext::ParseMessage(MessageLite*, const char*) is what a generated
_InternalParse calls for a submessage field and for nothing else, so flat
messages parsed and nested ones did not: a TranscriptResult carrying
segments serialized to correct bytes that the same process could not read
back, and TranscriptLiveRequest, a oneof of submessages, could not have
been parsed at all. Underneath that, 3.21 generated code was running 3.14
arena, ArenaStringPtr and ExtensionSet code.

-Wl,--exclude-libs does not fix it. It makes those symbols LOCAL in
.dynsym and the parse still fails, because the binding was decided at
static link time and no visibility flag revisits it.

Setting SPM_PROTOBUF_PROVIDER to "package" before add_subdirectory points
sentencepiece at the protobuf the generated code was already built
against. Zero google::protobuf:: definitions remain in the executable
afterwards, every nested message round trips, and citrinet_asr, which
parses a SentencePiece ModelProto at load time and would break first if
this were wrong, still tokenizes and transcribes correctly.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
…built from

Segment text is not decoration. core/http/endpoints/openai/transcription.go
routes response_format text, srt, vtt and lrc through
schema.TranscriptionResponse, which builds the entire body out of
Segments[].Text and never reads the top-level text. So for those four
formats the segment text IS the response.

nemotron_asr emits one word_timestamp per SentencePiece token, and the
word boundary is carried as a LEADING SPACE on the piece ("So", "me",
" call"). join_words inserted a space unconditionally, so
response_format=text returned "So me  call   me  na ture ," while the
correct sentence sat unread in the top-level field. The separator is now
chosen from the words themselves: whole words are space-joined, subword
pieces are concatenated, and one leading space anywhere selects the
latter. Concatenating the real nemotron pieces reproduces text_output
exactly, verified end to end.

This does not touch the top-level text, which is still text_output
verbatim. The rule that forbids deriving the transcript from the segments
is about the direction segments -> text; segment text has no source other
than its words.

Two smaller corrections in the same area:

timestamp_granularities ["word"] set only "word_timestamps", a key no
family in the pinned upstream reads. It now sets "return_timestamps",
which qwen3_asr does read and which both runs its forced aligner and
shortens its chunk window, so asking for word granularity no longer
silently returns nothing.

The request-option comment claimed more than it delivered. prompt,
translate and temperature are read by no ASR family, and are forwarded
only so a family adopting them works unchanged; the comment now says so
per key, and gives TranscriptRequest.diarize the same explicit treatment
threads already had.

Also: the shipping target now carries -Wall -Wextra -Wpedantic, which it
never did, so "the build is clean" starts meaning something; and
fill_transcript_result no longer swallows a null response pointer, since
answering OK with an empty transcript is the one failure mode this unit
exists to prevent.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Covers voice conversion, singing voice conversion, speech to speech and source
separation, the four tasks LocalAI's AudioTransform can represent.

AudioTransformResult carries one dst while htdemucs and mel_band_roformer
produce several named stems from a single run, so inference runs ONCE, every
stem is written as a sibling file <dst-stem>.<name>.<ext>, and params[stem]
selects which one dst receives, defaulting to vocals and falling back to the
first output. An unknown stem name is INVALID_ARGUMENT listing the real stem
names rather than a silent substitution, and the selection happens before the
first write so a refused request leaves no files behind. params[stem] is
consumed here and is not forwarded into the engine's request options.

The stem decision lives in stem_selection, which is stdlib only and therefore
tested by backend/cpp/run-unit-tests.sh. It also validates the names, because
they come from the model (htdemucs reads them from the GGUF's config.sources)
and each becomes a component of a path this backend writes: a name carrying a
path separator would escape the caller's output directory, and two stems
sharing a name would silently overwrite one another.

Both files are read at their native rate and channel count. Separation forces
it, since demucs and roformer refuse any rate but 44.1 kHz and lose the stereo
image that separates a centred vocal from a wide mix. The conversion families
all resample internally (seed_vc, vevo2, miocodec, chatterbox were each
checked), so passing the file through unchanged is also strictly better than
band limiting it to 16 kHz first.

Verified end to end against htdemucs f16 on a 44.1 kHz stereo mix: four stems
plus dst, dst byte identical to the selected stem, params[stem] selecting a
different one, an unknown stem refused with no files written, and mono input
preserved as mono output. Also against miocodec for the single output path,
where params[stem] is refused rather than ignored.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
… the caller for a failed write

Four fixes from the first review of the AudioTransform RPC.

check_can_serve now returns the resolved route, so params[stem] on a route that
is not source separation is refused from the route instead of after a full
inference: 11 ms rather than the 4.5 s a miocodec conversion costs, and far
worse on seed_vc or vevo2. The post-run refusal stays as the backstop for a
separation-routed family that returns no stems anyway. The typo'd-stem-name
case still needs the run, since no framework header publishes the stem names
before one.

Stem names carrying control bytes are refused. GGUF strings are length prefixed
and demucs reads its sources from JSON, so an embedded NUL survives to here:
two names differing only after the NUL are distinct std::strings, so the
duplicate check passes them, and then path::c_str() truncates both and they
open the same file. That is exactly the silent overwrite the duplicate check
exists to prevent, with the .wav lost as well.

A failed write is now INTERNAL rather than INVALID_ARGUMENT. The destination is
LocalAI's own generated-content directory, not anything the caller named, so a
full disk or a permission fault there is a server fault and is worth retrying,
which is the opposite of what INVALID_ARGUMENT tells a client. An empty output
path stays INVALID_ARGUMENT.

Two comment corrections and one clarification: the separators' required rate is
their checkpoint's declared samplerate rather than a hardcoded 44100, seed_vc
resamples with soxr and falls back to sinc-hann, and the "no files left behind"
guarantee covers a refused request, not a write that fails partway through the
loop.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
…name the separation stems

Two defects that made source separation unusable through LocalAI's own API,
even though the backend served it correctly over gRPC.

/audio/transform normalized every upload to 16 kHz mono s16 through
utils.AudioToWav, with no way past it. htdemucs and mel_band_roformer refuse
any rate but their checkpoint's own and separate a centred vocal from a wide
mix using the stereo image, so every separation request through the HTTP API
died with "HTDemucs prepare() sample rate mismatch: expected 44100, got 16000"
while the same call over gRPC worked. The fold is not wrong, it is
backend-specific: LocalVQE's echo cancellation genuinely wants 16 kHz mono and
needs the reference in the same shape. So it becomes a declaration,
BackendCapability.AudioTransformInputMono16k, set for localvqe and for nothing
else. A backend that declares nothing gets its upload unchanged, which means no
backend has to opt in to work. utils.AudioToWavPreservingShape is the
non-folding conversion: a 16-bit PCM WAV passes through byte for byte at any
rate and channel count, anything else is transcoded to WAV with its rate and
channel layout kept.

The other defect is that the run-once stem design bought nothing. A separation
backend writes every stem beside dst from one inference, but AudioTransformResult
carried only dst, so the other three were files no caller could find and a
caller wanting all four had to run four separations. AudioTransformResult grows
a repeated AudioTransformStem, the backend fills it, core/backend validates that
each path really is inside the generated-content directory it handed over, and
the endpoint publishes them as an X-Audio-Stems JSON header beside the existing
X-Audio-Input-Url. JSON because a stem name is the model's own string and could
contain any separator a hand-rolled format would use.

Verified end to end through the HTTP endpoint with htdemucs f16 on a 44.1 kHz
stereo file: 200 with a 44.1 kHz stereo body, all four stems named and fetchable
through /generated-audio/, body byte identical to the selected stem, and
params[stem]=drums returning a different one. The same upload sent to a model
whose backend is localvqe still reaches the backend as 16 kHz mono, confirmed
both by the engine's own rate refusal and by the persisted input file.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
mudler added 28 commits July 28, 2026 08:14
…efix

Rule 2 discarded any partial the known text merely started with. For a cumulative
family that is a duplicate; for an incremental family it is an ordinary short
fragment that happens to coincide with the start of the transcript, and it was
dropped, silently corrupting the text. Pure ASCII, no multi-byte character
anywhere: the fragments "pure ", "ascii ", "trans", "c", "ri", "p", "t" left the
client holding "pure ascii transcrit". Over 5,000 randomized traces per
transcript, 9.50% of pure-ASCII and 29.12% of French traces ended with the client
holding something other than final_result.text, with a 200 and no diagnostic.
Both incremental families emit fragments that small routinely, since nemotron_asr
cuts at a byte offset and vibevoice_asr at a common prefix.

Narrowing rule 2 to an exact repeat drives that to zero on all six transcripts
and changes no cumulative stream at all: 30,000 randomized cumulative traces are
byte-identical to the previous commit.

What rule 2 guarded was established from upstream rather than from its own
comment. The only duplicate any pinned family produces is voxtral_realtime's,
where process_available_stream_chunks feeds each event to the sink from inside
its loop and returns the last of the batch, so that event arrives twice with
byte-equal text. A duplicate is an exact repeat, so equality still covers it. The
case given up is a cumulative report that SHRINKS, which no pinned family can
produce: voxtral decodes a token vector that is only push_back'ed and cleared by
reset(), so within a stream it can only grow.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
The one bidirectional stream this backend serves. The client sends a
TranscriptLiveConfig, then TranscriptLiveAudio frames; the server acknowledges
with ready, emits deltas as the audio arrives, and sends final_result once the
read side closes. There is no offline fallback: live transcription has to
consume audio incrementally, so a family with no streaming ASR is refused
rather than served a batch run, which is what this RPC's Streaming-only
mode_candidates list already says.

The driver is a new sibling of run_streaming_audio, run_streaming_live, because
the audio does not exist yet: instead of slicing a buffer it pulls frames from
the caller until the read side closes. It installs the same ScopedStreamSink in
the same order, which is not optional, since nemotron_asr returns a bare event
from process_audio_chunk and reports every partial through the sink from inside
finalize(). It buffers the wire's frames up to the family's own preferred window
rather than feeding whatever size the client's audio callback produced, and it
does not call finish_stream at all when no audio arrived, because nemotron_asr
throws "finalize requires streamed audio" and an empty transcript is the
truthful answer to transcribing nothing.

Three things the handler had to get right and one it cannot:

  - The audio contract. A live request carries no samples, but nemotron_asr's
    streaming prepare() throws without an audio contract, and
    build_preparation_request derives it from TaskRequest::audio_input, so that
    field is an EMPTY buffer holding only the rate and the channel count.
  - 16 kHz or a refusal. The families express their spans in their own 16 kHz
    feature domain whatever the input was, and live frames cannot be resampled
    on the way in the way a file can, so an 8 kHz session would return
    timestamps 2x off with a 200. core/backend hardcodes 16000 anyway.
  - A mid-stream Config is refused. backend.proto calls it a decoder reset, but
    deltas already on the wire cannot be retracted, so a reset would leave the
    final text contradicting the transcript the client assembled. Ignoring the
    message would hand a client that believes it reset the decoder a transcript
    that silently continues the audio it thought it discarded.
  - The stale-route identity check cannot run here: TranscriptLiveRequest
    carries no ModelIdentity in either arm of its oneof, so snapshot_for does
    not instantiate for it. snapshot_unchecked's comment now names that as a
    second legitimate class of caller and says the fix is a proto change.

eou and eob stay false. They exist for cache-aware models that emit
end-of-utterance and end-of-backchannel tokens; audio.cpp's StreamEvent has no
equivalent signal, and a client uses eou to decide the speaker yielded the turn,
so a guess inferred from silence cuts people off mid-sentence.

The lane is held for the whole stream, which is as long as the user keeps
talking: the streaming session is stateful and cached, so a concurrent run would
interleave two callers' audio and corrupt both transcripts.

Verified against nemotron_asr over a real connection with a 14 s WAV in
512-sample frames: ready first, 59 incremental deltas with no repeated prefix,
concat(deltas) equal to final_result.text, word timestamps in nanoseconds, eou
and eob false. citrinet_asr answers UNIMPLEMENTED naming the family and listing
asr/offline. A config followed by a close returns an empty final_result rather
than hanging, and a first message that is not a config is INVALID_ARGUMENT. Two
concurrent streams both return the complete transcript.

Two cleanups on lines Task 12 touched, folded in. The DtypeAllowList terminator
is now asserted at compile time: the reported out-of-bounds read did not exist,
the single entry does terminate, but the loops have no other bound and any edit
that widened an entry would walk off the end. And the dtype guard now
short-circuits on "is there a table entry" through a new predicate rather than
on the emptiness of the description string, which would have skipped the check
on an entry with an empty allow list, i.e. on precisely the entry that refuses
every dtype.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
AudioTranscriptionLive holds the model's inference lane for the whole stream,
which is correct (the streaming session is stateful and a concurrent run would
interleave two callers' audio) and newly dangerous. Every other RPC holds the
lane across compute, or across a write to a slow reader, and both of those
terminate on their own. A live stream instead blocks in a client-driven read,
and a peer that goes silent WITHOUT closing the stream never terminates
anything: the lane stays taken and every other request against that model queues
behind a client that stopped speaking.

live_watchdog is a one-shot idle timer that ends the stream when no frame has
arrived inside a window. It is standard library only, so it is unit tested
without an engine. gRPC's synchronous Read has no timeout and cannot be given
one, so the only way to unblock it is ServerContext::TryCancel, which decides
the wire status itself: the client sees CANCELLED rather than the
DEADLINE_EXCEEDED the handler returns, the reason is logged, and the lane coming
back is the point. When it fires the read loop throws rather than reporting
end-of-input, so the driver does not go on to finalize a decode nobody is
waiting for.

It is armed only after the lane is taken and disarmed as soon as the read side
closes, and both ends matter. Arming earlier would cover acquire(), which
legitimately blocks while another live stream runs, so a queued caller would be
cancelled for waiting its turn. Disarming later would cover our own decode,
where a window overrun is not a peer going quiet and cancelling would throw away
the transcript the client is waiting for.

The window is the new live_idle_timeout_ms option, 30 s by default, 0 meaning no
limit. core/http/endpoints/openai/realtime.go drives a 300 ms ticker and feeds
every tick that produced new audio while a turn is open, so 30 s of silence is a
hundred ticks that delivered nothing. It is also longer than any pause a speaker
takes mid-utterance, which is the case that must never be cut off, and
backend.proto lets one stream span many utterances, so a client that pauses
longer between them raises the option rather than discovering it.

Two smaller corrections in the same handler:

  - check_can_serve now runs BEFORE the sample rate check.
    pkg/grpc/grpcerrors/errors.go degrades to the file path on UNIMPLEMENTED and
    on nothing else, so a live-incapable model asked at a wrong rate was
    answering INVALID_ARGUMENT and costing the caller its fallback.
  - a negative sample rate is refused instead of silently becoming 16000. Zero
    still means 16000, which is what the proto documents; -1 is malformed rather
    than absent and gets the same refusal every other bad rate gets.

And one thing recorded rather than changed, at the handler: "live" here means
incremental INPUT, not low latency, and with the pinned families it does not yet
mean incremental OUTPUT either. nemotron_asr's process_audio_chunk only appends
to its buffer, so its whole decode and every delta happen inside finalize(),
after the client closes its send side. The policy-window buffering is inert for
that family and matters only for vibevoice_asr and higgs_audio_stt.

Verified on the wire with live_idle_timeout_ms:3000. A silent client acked at
371 ms and was cancelled at 3.371 s; a second live stream opened one second
later received its ack 2.37 s in, i.e. at the instant the first was cancelled,
and then transcribed successfully on the same cached session. Without the
watchdog it would still be waiting. Re-ran the live transcription (ready first,
59 incremental deltas, concat equal to the final text, word timestamps in
nanoseconds, eou and eob false), the citrinet refusal at both a right and a
wrong rate (UNIMPLEMENTED either way now), and Task 12's AudioTranscriptionStream
on nemotron_asr, which is unchanged.

Mutation testing the watchdog found a weakness in its own test: the destructor
test slept past the window inside the watched scope, so a destructor that
DETACHED the thread instead of joining it passed unnoticed. The test now uses a
window longer than the scope, which kills that mutant, and says why.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
AudioEncode, AudioDecode, AudioTransformStream, AudioToAudioStream and
VoiceEmbed have no counterpart in audio.cpp's VoiceTaskKind. Each now returns
UNIMPLEMENTED naming the loaded family, what that family does support, and the
upstream limitation, instead of the generated base class's bare status. The
reasons live in a table in capability_routing.cpp so they are data rather than
literals copied into five handlers, and so a test can assert every one of them.

The five claims this was planned against were re-read at the pinned upstream
e800d435d130dc776baf6f3e6129bb62b1495c89, and one did not hold. "audio.cpp
streams tts and asr only" is false: silero_vad advertises vad with
RunMode::Streaming. The refusal stands on the narrower claim that survives, that
no family advertises streaming for any task AudioTransform routes to, and a test
asserts the refuted wording does not come back.

VoiceEmbed is the one refusal whose request carries a ModelIdentity, so it runs
the #10952 check before answering: a stale route must get NOT_FOUND and the
router's sentinel, not "audio.cpp cannot embed speakers" about a model that is
not loaded here. It cannot use snapshot_for, whose no-model branch would tell
the caller to load a model when no model can help, so it takes the reference
through snapshot_unchecked and checks identity itself. That function's comment
now names three classes of caller instead of two.

The two bidirectional surfaces refuse without reading their stream, verified
with a client that writes a config and eight frames first and gets the status
rather than hanging.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Review found a false clause in the AudioToAudioStream refusal. It said s2s is
"offline voice conversion ... which converts one clip into another speaker's
voice", which is true of miocodec and false of vevo2: vevo2's s2s route is
`editing` and only `editing` (default_route_for_task and route_matches_task in
src/models/vevo2/session.cpp), documented as "Edit source speech into new target
text while using the target voice" and requiring --target-text, so it rewrites
what was said. vevo2's voice conversion is its separate vc task. It now reads
"offline clip-to-clip processing against a target voice, declared only by
miocodec (voice conversion) and vevo2 (speech editing)", and a test asserts the
miscast cannot come back. The conclusion is unchanged: neither family converses.

That defect was undetectable on the wire, since vevo2 does not load here, which
is the argument for upstream_absence_ctest.cpp. It links engine_runtime purely
to interrogate make_default_registry() and asserts the five premises the refusal
reasons rest on: no codec task kind, no family advertising spk, no streaming for
sep/vc/svc/s2s, miocodec advertising exactly vc and s2s, and s2s advertised by
exactly miocodec and vevo2. The last two are exact sets, so an addition fails
here rather than leaving a message stale. A positive control proves the registry
is populated and the query works before any absence is believed, and every
assertion has a reproduced negative control. This turns an AUDIO_CPP_VERSION
bump from "remember to re-read five prose paragraphs" into a test failure.

unsupported_surface now switches over UnsupportedRpc with no default label, so
-Wswitch reports a sixth enumerator added without a row at build time; the
runtime bounds guard it replaces is deleted.

The AudioTransformStream reason had a true premise and an overreaching
conclusion: an offline sep family could be buffered into a stream, as other
LocalAI backends do. It now says this backend declines to offer a buffered
offline call in disguise, rather than implying impossibility.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
unsupported_surface() switches UnsupportedRpc onto the table row that explains
it, with no default label, so -Wswitch reports an enumerator nobody handled. As
a warning that is not enough: adding a sixth enumerator and building the shipping
target gives exit 0, a binary and one warning, and the trailing
`return surfaces[0];` then answers the new RPC with AudioEncode's codec reason.
That is a confident, specific and false statement about audio.cpp on the wire, on
the one code path whose entire job is to be truthful about what this backend
cannot do, and it is worse than the runtime fallback it replaced, which at least
named itself as a bug in this file.

capability_routing.cpp therefore joins loaded_model.cpp on the existing
-Werror=switch pin, whose comment already made this argument for the engine enum.
The comment now covers both files. The pin stays per-file rather than
project-wide because upstream's own ace_step/vae_decoder.cpp has unhandled
-Wswitch cases of its own.

Verified: a sixth enumerator now fails `make grpc-server` with exit 2 and no
binary; appending a 14th VoiceTaskKind upstream still fails loaded_model.cpp, so
the two pins fire independently; both reverted clean.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Bundles the dependency closure for the from-scratch image, the dlopened ggml
CPU-variant shared objects that ldd cannot see, and upstream's bundled
silero_vad and marblenet_vad assets so VAD works with no download.

The bundled loader sits in the package ROOT rather than at lib/ld.so. run.sh
execs it, which makes /proc/self/exe name the loader, and this backend has two
consumers of that path: ggml discovers the libggml-cpu-*.so by listing
dirname(/proc/self/exe), and resolve_model_path expands bundled:<name> under the
same directory. Rooting the loader makes the binary, the ggml objects and
assets/ share the one directory all three resolution mechanisms agree on.
llama-cpp's lib/ld.so layout would need assets/ moved into lib/ as well.

The image builds against apt gRPC and protobuf, like Dockerfile.ds4 and unlike
Dockerfile.privacy-filter. The from-source gRPC that install-base-deps.sh and
the base-grpc-* images supply vendors protobuf 26, which pulls abseil into
message_lite.h; with SPM_PROTOBUF_PROVIDER=package that collides with
sentencepiece's vendored mini-abseil and every absl::internal reference becomes
ambiguous. Noble's protobuf 3.21.12 predates the abseil dependency and is the
pair every earlier verification of this backend ran against.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
package.sh already left libcuda.so* and libnvidia-* to the host when copying,
because the driver has to match the kernel module on whatever host runs the
image, but the validation gate had no matching exemption. With BUILD_TYPE=cublas
ggml is static and links CUDA::cuda_driver, so grpc-server carries DT_NEEDED
libcuda.so.1 and the gate would have rejected the very absence the copy loop
created, failing every cublas build in CI. One regex now feeds both.

Building a control for that found a second defect: ld.so --list refuses to trace
an object with an unresolvable dependency at all, exiting 127 without emitting a
per-library line, so the "=> not found" rule was dead code and no exemption could
have applied to it. The gate now traces with LD_TRACE_LOADED_OBJECTS and
LD_LIBRARY_PATH, which reports the missing name and exits 0, and which is also
what run.sh does at run time.

Adds a layout assertion so a future move of the loader into lib/ fails the build
instead of shipping a package that resolves bundled: models into lib/assets and
finds no ggml CPU backend, and records for Task 16 that the Darwin script must
not be a straight copy of privacy-filter-darwin.sh, which never calls package.sh
and would silently drop assets/.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Adds the five Linux matrix entries (cpu amd64/arm64 sharing a tag-suffix so the
manifest merge fires, cuda 12, cuda 13, vulkan), the path-filter case that keeps
later PRs touching backend/cpp/audio-cpp/ from getting zero CI jobs, the
bump-bot entry pointing at the AUDIO_CPP_VERSION pin in the backend Makefile,
the gallery meta plus its -development variant and the image entries for every
variant, and the Makefile docker-build wiring.

The matrix entries carry base-image only, with no builder-base-image, unlike
the llama-cpp and privacy-filter blocks they sit next to. The prebuilt
quay.io/go-skynet/ci-cache:base-grpc-* images ship a from-source gRPC whose
protobuf v26 depends on abseil, and this backend's sentencepiece is built with
SPM_PROTOBUF_PROVIDER=package, so it sees real abseil's absl::lts_20240116::
internal alongside its own vendored plain absl::internal and every
absl::internal:: reference becomes ambiguous. Building against base-grpc-amd64
fails at sentencepiece-static.dir/error.cc.o with "reference to 'internal' is
ambiguous". Dockerfile.audio-cpp installs apt's gRPC/protobuf 3.21.12 itself,
which is also the pair every unit and end-to-end run of this backend has been
verified against, and the CUDA toolkit therefore has to come from base-image.

No Darwin matrix entry and no metal gallery entries: the Metal build needs
scripts/build/audio-cpp-darwin.sh, a backends/audio-cpp-darwin make target and
a routing step in backend_build_darwin.yml, none of which exist yet, so an
entry added now would be routed to build-darwin-go-backend and look for
backend/go/audio-cpp/. The inferBackendPathDarwin case and the
DARWIN_BESPOKE_BUILDERS membership are in place, inert, so that adding the
entry later is a one-line change that cannot be claimed by the generic Go path.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Upstream sets CUDA_ARCHITECTURES to `native` on the engine_runtime target
whenever CMAKE_CUDA_ARCHITECTURES is unset at root scope, and docs/build/
linux.md says so outright. ggml's own default does not rescue it: it
list(APPEND)s in the ggml subdirectory scope, which never reaches the root
scope where the engine_runtime property is decided. No CI runner has a GPU for
`native` to enumerate, so both cublas entries would have gone red on the very
commit that first turns a CUDA build on.

Pin the list in backend/cpp/audio-cpp/Makefile, selected by CUDA_MAJOR_VERSION,
which Dockerfile.audio-cpp now forwards from the CI build-arg it was previously
discarding. The values are copied from ggml's own version guards rather than
invented, so engine_runtime and ggml compile for the same set: CUDA 12 keeps the
Maxwell/Pascal/Volta virtual archs and stops at 120a-real, CUDA 13 drops them
and adds 121a-real. The `a` suffix is used rather than `f` because the latter
needs CMake 3.31.8 and Ubuntu Noble ships 3.28.3. Verified by driving CMake
3.28.3's own CUDA architecture validator over both lists, with 120f-virtual as
the rejected control.

Drop the vulkan matrix entry, its two gallery entries, the vulkan capability
key on both metas and the Vulkan tag. Every other vulkan backend gets its Mesa
ICD drivers from .docker/install-base-deps.sh, which package-gpu-libs.sh then
bundles; Dockerfile.audio-cpp calls neither and installs only libvulkan-dev and
glslc, so the image would ship a Vulkan loader that finds no GPU. No CI job runs
a vulkan image against real hardware, so that would have passed green and failed
in users' hands. BUILD_TYPE=vulkan stays supported for local builds.

Also note on the cublas entries that cuda-major-version now selects the
architecture list and that cuda-minor-version and the base-image tag encode the
same toolkit, and correct the stale entry counts on matrixEntryKey.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Bespoke C++ Darwin path like ds4 and privacy-filter: an includeDarwin matrix
entry, a backends/audio-cpp-darwin make target, a gated workflow step, and the
metal image entries plus metal/metal-darwin-arm64 capability keys in the
backend gallery.

The build script deliberately does NOT reassemble the package the way
privacy-filter-darwin.sh does. It runs the backend's own `make package` and
copies the result, so the Darwin package keeps the root-level layout the Linux
one has: grpc-server, run.sh, the ggml objects and assets/ in one directory,
with lib/ for the dylib closure. Hand-assembling would drop assets/, and
assets/ is what makes the bundled: model paths resolve with nothing downloaded.
The dylib walk is a full transitive closure rather than the single level ds4
and llama-cpp do, because Homebrew's grpc++ pulls libgrpc, abseil, upb, cares
and OpenSSL that grpc-server does not link itself, and a level-1 walk ships a
package that only works on a machine that already has Homebrew grpc.

Two fixes folded in, both in the backend Makefile:

  - an EMPTY CUDA_MAJOR_VERSION fell through to the CUDA 12 architecture list,
    which contains 120a-real and so needs nvcc >= 12.8. A local
    BUILD_TYPE=cublas build on a 12.0-12.7 host failed to compile where
    upstream's documented default (native) worked. EMPTY now maps to native,
    12 and 13 keep their lists, and any other non-empty value is an error on
    cublas builds. CI always passes a major, so CI is unaffected.

  - the Darwin branch now points CMake at Homebrew's keg-only libomp. AppleClang
    ships no OpenMP runtime and nothing is symlinked into /opt/homebrew, so
    FindOpenMP finds neither the library nor the header, and audio.cpp calls
    find_package(OpenMP REQUIRED) whenever ENGINE_ENABLE_OPENMP is on. Without
    the hint the macOS build would have died at configure time. If the keg is
    absent the build disables OpenMP instead of failing.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
… complete

Review follow-up on the Darwin Metal build.

The OpenMP fallback was silent. If brew --prefix libomp ever comes back empty,
CI produced a green Metal package with 108 #pragma omp directives across ~30
files compiled out, and clang says nothing about an ignored omp pragma without
-Wsource-uses-openmp, so the only trace was one absent flag inside a set -x
cmake line. That regression would have been blamed on Metal. It now warns.

The @rpath arm of the dylib walk had no live candidate when it was written, on
the reasoning that a Metal build links ggml statically. The OpenMP fix in the
same commit made libomp.dylib one, and whether Homebrew records it as an
absolute opt path or as @rpath/libomp.dylib is not observable from Linux. The
walk now expands @rpath, @loader_path and @executable_path against the object's
own LC_RPATH entries, and only fails when nothing on disk answers, printing the
rpath list with the error so a failure on a machine nobody can attach to
explains itself.

Also: ADDITIONAL_LIBS now go through the closure rather than a bare cp, so they
are deduplicated and their own dependencies bundled; build/darwin/lib is
created explicitly instead of relying on package.sh pre-creating it; the libomp
probe uses nested ifneq rather than $(and ...), which needs GNU make 3.81 and
would otherwise expand empty and take the OFF branch on an older make; and
-DOpenMP_ROOT is quoted like its CUDA sibling.

Verified with a Linux harness that runs the script verbatim against a stubbed
otool: a level-2 transitive dep, an @rpath dep reachable only through LC_RPATH,
and an ADDITIONAL_LIBS dep are all bundled, a dependency cycle terminates,
system libraries are skipped, the packaged tree has assets/ at the root beside
grpc-server with the dylibs in lib/, and both failure paths exit non-zero.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
resolve_model_path() tested the bundled: prefix on `candidate`, which prefers
ModelFile and falls back to Model. LocalAI fills ModelFile by joining ModelPath
onto the configured model string (pkg/model/loader.go, LoadModelWithFile), and
only sets it from a managed artifact otherwise, so a model YAML saying
`model: bundled:silero_vad` arrives as ModelFile "/models/bundled:silero_vad"
and Model "bundled:silero_vad". The prefix therefore never matched through the
normal load path: it matched only for a hand-written LoadModel call that left
ModelFile empty, which is exactly how task 15 verified it, and every model YAML
using the form failed with "model path does not exist:
/models/bundled:silero_vad".

Both fields are now checked, Model first, so the zero-download VAD path the
package ships assets for is reachable the way it is documented. A caller that
puts the form in ModelFile still works, so task 15's verification stands.

Compiled clean; the runtime check could not run on this host, whose system
libprotobuf/libre2 have gone missing (the pre-existing grpc-server binary no
longer resolves its libraries either), so it wants a container run.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Registers audio-cpp as preference-only in /backends/known: the family lives in
GGUF metadata that an importer cannot read from a remote repo, and one repo
hosts thirty families, so there is no honest auto-detect signal. Modality is a
single string and the import form chips on a fixed key set, so it registers as
tts with the other modalities named in the description rather than under an
invented key the UI would bucket as "other".

Adds a features page covering the option namespacing, the routing table per
endpoint, the RPCs this backend declines and why, the bundled VAD path, the
separation stem behaviour, and the family gotchas (supertonic needs the orig
package; chatterbox advertises cloning and no plain tts; nemotron_asr defers
its whole decode to finalize so live transcription emits nothing until the
client half-closes, unlike higgs_audio_stt and voxtral_realtime). Every option
name and family capability in it was read off the pinned upstream checkout.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
…ames

The bundled: fix in 842443c shipped without a test, which is how the bug got
there: task 15 verified the form with a hand-written LoadModel that left
ModelFile empty, and that is the one shape the server never produces. Four cases
in streaming_driver_ctest, which already links loaded_model.cpp, pin the
PRODUCTION shapes instead. The first fails against the pre-fix source (returns
the joined /models/bundled:silero_vad); the other three are the branches the
bundled: lookup now runs in front of and must fall through for.

Three family names in the docs were the source directory rather than the
registered family, on pages whose whole argument is that these names cannot be
guessed: demucs is htdemucs (demucs/loader.cpp:22), roformer is
mel_band_roformer (roformer/assets.h:15), and moss is TWO families,
moss_tts_local and moss_tts_nano. The hyphenated ASR names are underscored to
match, here and in the compatibility table.

The supertonic dtype note claimed more than the evidence carries. The f16 abort
is a local observation, identical through TTS and TTSStream; upstream's
docs/gguf.md leaves the 16-bit column untested and records q8_0 as "No
(unsupported weight dtype)", which says unusable rather than fatal. Both are
still refused, because the allow list is what the family can run. Corrected in
family_gate.h, family_gate.cpp and the docs together, since the docs inherited
the wording from the code.

The importers tripwire says in the file that it is a tripwire: it exercises no
audio-cpp behaviour, and the registration assertion lives in backend_test.go.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
One representative model per RPC group of the audio-cpp backend, plus the two
bundled VAD models, which need no download at all because the assets ship
inside the backend package.

Every hash was computed with sha256sum on the downloaded file. Quantizations
come from upstream's tested-status table in docs/gguf.md rather than a default
of q8_0: supertonic ships the orig package (its q8_0 is recorded as an
unsupported weight dtype and its f16 aborts in ggml_concat), and nemotron_asr
and htdemucs ship f16 because their q8_0 builds are recorded with drift while
16-bit is a clean pass.

Diarization and separation use the diarization and audio_transform usecases,
not transcript: /v1/audio/diarization and /audio/transform filter the default
model on FLAG_DIARIZATION and FLAG_AUDIO_TRANSFORM respectively, so a
transcript flag would have hidden both models from their own endpoints. The
forced aligner sets parameters.language, which the transcription endpoint uses
as the fallback when no language form field is sent, because the family
requires both a transcript and a language.

All ten entries were run twice: once against the raw gRPC server, and once
installed with local-ai models install and called through the HTTP endpoint.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Swept all ten entries against the real upstream named in audio.cpp's
tools/model_manager.py rather than against the audio.cpp repo's own license.
Three were wrong:

  supertonic   apache-2.0 -> openrail      weights come from
                                           mlx-community/supertonic-3-mlx, and
                                           both it and Supertone/supertonic are
                                           openrail
  citrinet     apache-2.0 -> other         pulled from NGC
                                           nvidia/nemo/stt_en_citrinet_256,
                                           governed by the NGC Terms of Use
  sortformer   other -> cc-by-nc-4.0       nvidia/diar_sortformer_4spk-v1 is
                                           CC BY-NC 4.0, and the gallery already
                                           uses that exact string, so there is no
                                           reason to obscure a non-commercial bar

The license field is one word, so citrinet and sortformer also gained a
sentence saying why they are restricted. The other seven were confirmed
correct against their sources.

Also drops an unverified claim from the nemotron description. It said the
model drives the realtime transcription session; that endpoint actually calls
TranscribeStream, and the live RPC reaches LocalAI only through
realtime_semantic_vad.go. Neither path was exercised here, so the description
now states only the two calls that were.

MarbleNet gains the NeMo upstream under urls: for parity with silero.

No sha256, quantization, usecase or model choice changed.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Four defects the whole-branch review found on the Go side, plus two comment
corrections.

sample_rate is a disk-exhaustion hazard. The branch added the `form:` tag that
makes the field bind for the first time, so the resample path went from dead to
live, and utils.AudioResample interpolates the int straight into ffmpeg's -ar
with no bound. Measured with ffmpeg 7: -ar 999999999 on a 0.01 s clip writes
20 MB and exits 0, which scales linearly to the reported 3.9 GB for one second,
into a GeneratedContentDir nothing sweeps, and convertStems repeats it once per
separation stem. Clamped to 8000..192000 in the handler, before the temp dir and
before the model is touched, and rejected with a 400 outside it.

The low end was reported as "a 0-byte file". It is not: -ar 1 writes a 78-byte
header with no audio behind it, whose declared data size still claims 70 bytes,
so go-audio parses it as a 35 SECOND file and a size check does not see it. The
guard therefore compares the declared data chunk against the bytes actually on
disk, and AudioResample now fails rather than returning a WAV carrying nothing.

Both parts of a transform request land in one temp dir, and the raw copy was
named only after the client's basename, so `-F audio=@mic/clip.wav
-F reference=@loopback/clip.wav` wrote "raw-clip.wav" twice. Since
AudioToWavPreservingShape hardlinks an already-PCM16 WAV rather than copying it,
the reference part's os.Create truncated the inode audio.wav pointed at: mic and
reference came out identical, which makes an echo canceller null everything and
return near-silence with a 200. The raw copy now carries the form field name.

audio-cpp had no BackendCapabilities entry, so VoiceCloningForModel returned nil
before it ever consulted the model's tts.voice_cloning override and every
`voice: "profile:<id>"` request was refused with a 400, on a backend that ships
audio-cpp-chatterbox whose family serves cloning and not plain TTS. Registered
with its RPCs, usecases and the reference-audio contract, and deliberately
without the 16 kHz mono fold, which its separation families cannot survive.

GetBackendCapability was exact-match only, so every pinned gallery variant read
as an unknown backend: vulkan-localvqe lost the 16 kHz mono fold that used to be
unconditional and started failing inside LocalVQE, and the usecase gate does not
stand in for it because BuildFilteredFirstAvailableDefaultModel returns early
once the client names a model. Lookup now falls back to the meta name by
stripping the gallery's hardware prefix and release-channel suffix, exact match
first so nothing can be shadowed. Same class as #10945.

Also corrected: the AudioTransformRequest comment claimed echo's binder falls
back to the field name, which it does not in either direction (bindData binds
ONLY tagged fields and `continue`s otherwise; `model` arrives from
setModelNameFromRequest's c.FormValue). And the stable_audio `src` heap
corruption caveat now lives on ElevenLabsSoundGenerationRequest, where the Go
developer who would add the field can see it, instead of only in C++.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
…y frames holding the lane

The model's `task:` option is copied into the request shape by all nine
handlers, which is correct, but resolve_route then replaced the RPC's candidate
list with the pin WHOLESALE and never asked whether the pin was something that
RPC routes to. One pin therefore bled across all nine surfaces, and because the
family still supported the pinned task the result was a wrong 200 rather than an
error. Reproduced live: nemotron with task:asr made Vad return 200 with zero
segments after a full ASR decode, so 14 seconds of speech was reported as
silence, and Diarize did the same; silero_vad with task:vad made
AudioTranscription return 200 with empty text and four segments whose spans were
VAD segments, which combined with response_format in {text,srt,vtt,lrc} building
the body solely from Segments[].Text yields a well formed SRT of four timed
EMPTY cues. It also contradicted the documented contract, that a family which
cannot serve a request is refused rather than rerouted.

A pin is now checked against the RPC's admissible task set before it is adopted,
and the refusal names both the pin and the RPC. The set is derived from
task_candidates with every shape flag set rather than restated, so a task added
to an RPC's candidates cannot become inadmissible by omission. Every legitimate
pin survives, and the test asserts all fifteen of them alongside the eight
crossings that must not.

The live watchdog was defeated by empty frames. idle.touch() ran on ANY message,
before the has_audio and pcm.empty() filters, so a peer writing unset-oneof or
zero-length frames faster than the window held the lane indefinitely while
feeding the decoder nothing. There is one lane per model and one model per
process, so that is a single client denying the whole backend, which is what the
watchdog exists to prevent, and the thrown text already said "no audio frame
arrived". The touch moved below the filters, which are now a named predicate so
the distinction is testable rather than a call order nobody can see.

Three comments corrected against measurement rather than reasoning:

- CMakeLists claimed zero google::protobuf:: definitions remain in the
  executable. nm -C --defined-only reports 2515, and that is expected: they are
  generated code, sentencepiece::ModelProto's own _InternalParse among them. The
  claim that holds, and the one the ABI fix is actually about, is that no
  vendored protobuf RUNTIME is linked and ParseContext::ParseMessage is
  UNDEFINED in the executable, resolving to libprotobuf.so.
- refuse_cloning_without_a_clip's "cannot misfire" paragraph had its reasoning
  backwards. Routing picks VoiceCloning as the FALLBACK when there is no clip,
  which is the case being caught; chatterbox, which ships in the gallery,
  advertises clon and no tts at all, so every voice-less request lands there.
- audio_units read "2.1 min at 96 kHz" for index 11289602, which is 1.96 min.
  2.1 min is 96 kHz's OWN first failure at 12288002. Both were remeasured and
  the note is now a per-rate table.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
…rden the darwin walk

run-unit-tests.sh pruned */llama.cpp/* but not */audio.cpp/*. It is safe today
only by luck: upstream's 44 tests all put "test" at the FRONT of the filename
(17 test-*.cpp, 27 test_*.cpp, zero *_test.cpp), so the glob misses every one of
them, and nothing enforces that. This gate runs on every PR for every backend
and compiles each match as a standalone translation unit with nothing but
nlohmann/json on the include path, so the day upstream adds or renames one test
the gate goes red repo-wide on an Apache-2.0 file nobody here wrote.

audio-cpp-darwin.sh now logs the raw otool -L output and the parsed LC_RPATH
list unconditionally, before the walk. Both awk filters in that script assume a
column layout nobody working on this can observe, since it runs only on the CI
Mac, and a green first Darwin run proves nothing about the assumption: an awk
that silently matched nothing yields an empty dependency list, which reads
exactly like "no non-system dependencies" and packages happily. Both filters
otherwise feed process substitutions, so their input never reached the log.

It also lists every symlink in the package and fails on one that cannot resolve
inside the image. A dangling link does not fail anything else here, because
every assertion tests with -e, which follows links; it fails at dlopen on a
user's Mac. Links are NOT banned outright, which the review suggested but which
would break the libggml.dylib -> libggml.0.dylib chain the `cp -a` above exists
to preserve. What is banned is a link that resolves on the build host and will
not resolve in the image: a broken one, or an absolute one pointing outside the
package.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Follow-up to a84b3c4, no behaviour change.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Making GetBackendCapability strip the gallery hardware prefix and release
channel fixed pinned variants of /audio/transform, but VoiceCloningForModel
kept keying its per-backend switch on the caller's spelling. A pinned name
therefore resolved the capability by stripping and then missed every case in
the switch, falling through to the permissive default: cuda12-vibevoice-cpp
advertised voice cloning for the realtime 0.5B model, metal-coqui for
tacotron2, cuda12-crispasr for a pure ASR model, cpu-qwen3-tts-cpp for
CustomVoice. Each of those is a model that cannot clone, so /v1/audio/speech
accepted a profile: voice it had to fail on inside the backend rather than
rejecting it with a 400, and the UI advertised the capability too.

resolveBackendCapability now returns the key the entry was found under, and
callers that branch on backend identity use that key instead of the name they
were handed. The exact-match-first order is unchanged, so a backend genuinely
registered under a variant-looking name still keys on its own name.

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Assisted-by: Claude:claude-opus-5 [Claude Code]
Chatterbox advertises VoiceCloning AND VoiceConversion
(src/models/chatterbox), and the entry's own description already said so, but
known_usecases listed only tts. /audio/transform selects its default model by
FLAG_AUDIO_TRANSFORM, so voice conversion was reachable only by naming the
model explicitly and was invisible to every usecase-driven surface. It is the
one audio.cpp task with a shipped gallery model and no way to find it.

Verified against the real model rather than inferred from the capability list:
AudioTransform with chatterbox-q8_0, speech as audio_path and a speaker clip
as reference_path, returns a 5.08 s 24 kHz mono WAV at -25.5 dB mean and zero
stems, which is the single-output shape voice conversion should have.

The description now says which endpoint reaches that half and warns that
installing this next to a source-separation model gives /audio/transform two
candidates, so the model should be named rather than defaulted.

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Assisted-by: Claude:claude-opus-5 [Claude Code]
…ries

Two of the three audio.cpp task kinds that had no gallery model now have one.
Both were driven end to end against the real weights through the backend
before being written, not inferred from the capability tables.

audio-cpp-irodori-voicedesign covers vdes. TTS carrying `instructions` routes
to the vdes task, so the voice is described in words rather than supplied as a
clip. Verified: "a calm elderly woman speaking slowly with a warm, gentle
tone" over an 8.76 s 48 kHz mono render at -16.8 dB mean, and a closed-loop
citrinet pass recovers the sentence with the accent drift expected from a
Japanese-first model read by an English recogniser.

audio-cpp-seedvc-singing covers svc, and pins task:svc because nothing else
can reach it. seed_vc advertises svc and ordinary voice conversion, no request
signal means "this input is singing", and auto-routing resolves the tie to
voice conversion every time. Verified with the pin: 5.04 s 44.1 kHz output
whose closed-loop citrinet transcription is exact.

s2s deliberately has no entry, and the reason is not effort. miocodec is the
only upstream family whose speech-to-speech route needs no text, and it
returned audio with correct duration and level but no recoverable speech in
four independent attempts: the stale build, v2 q8_0, v2 orig (the variant
upstream records as a clean Pass), both tasks, and matched 44.1 kHz inputs on
both sides. vevo2's route refuses with "Vevo2 text/prosody route requires
text_input or target_text", and session.cpp:897 fills target_text only from
request.text_input, which AudioTransform has no field to carry. The same
vevo2 weights convert voice correctly through the default route with an exact
ASR round trip, so the model and the plumbing are both healthy; it is the s2s
route specifically that this RPC cannot express.

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Assisted-by: Claude:claude-opus-5 [Claude Code]
…entry

AudioTransform is audio-in / audio-out and its proto message has no text
field, but not every task it routes to is audio-only. vevo2's speech-to-speech
route is a text and prosody route: session.cpp:897 fills refs.target_text from
request.text_input and nowhere else, and the run refuses without one with
"Vevo2 text/prosody route requires text_input or target_text". The params map
is the only channel this RPC has that reaches the engine, so the text travels
through it and apply_transform_text_input unpacks it after the params have
been copied into task.options.

Before this, s2s was not awkward to reach through /audio/transform, it was
unreachable, and it was the last audio.cpp task kind with a real model and no
way to get to it.

target_text is canonical and text is its alias, the order vevo2's own option
table declares them in, so a request setting both gets the canonical one
rather than whichever the map happened to store first. An empty value falls
through to the next candidate instead of ending the search. language rides
along only when a text was found: on its own it conditions nothing, and
manufacturing a text_input for it would route a plain separation request
carrying a language hint through the text path. The keys are left in
task.options rather than erased, because vevo2's loader advertises target_text
as a request option and a family reading it there keeps working.

Nine tests, all confirmed failing on behaviour against a stub that returned
false before the implementation was written. Verified end to end afterwards:
vevo2-q8_0 with task:s2s and params[text] returns a 5.12 s 24 kHz output whose
closed-loop citrinet transcription is exact, and htdemucs separation with no
text param still returns its four stems, with and without params[stem].

audio-cpp-vevo2-speech-to-speech ships that route. Every audio.cpp task kind
with a loadable family now has a gallery entry; spk remains the only gap and
has no family upstream at all.

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Assisted-by: Claude:claude-opus-5 [Claude Code]
The text channel and the two task pins are both invisible from the endpoint
contract alone: nothing in the AudioTransform form tells a reader that a
speech-to-speech model needs the line it is resynthesising, and nothing says
that asking for singing voice conversion without task:svc silently gets plain
voice conversion instead. Both are the kind of thing a user only discovers
from a refusal or, worse, from output that looks right and is not.

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Assisted-by: Claude:claude-opus-5 [Claude Code]
gosec flags os.Open on a variable path, and both new call sites in ffmpeg.go
are its alerts on this PR. Neither is reachable by an outside caller: isPCM16Wav
opens the exact path it is about to hand ffmpeg as input, which in the upload
path is a server-created temp file named from path.Base of the client name so
no traversal survives, and wavAudioBytes opens AudioResample's own dst, a name
this package derives from src and has just had ffmpeg write.

Annotated in the repo's existing style rather than restructured, with the
reason spelled out, because a bare suppression is worth nothing to the next
reader. The three other G304 sites in this file, in passthroughWAV and
isTargetWav, predate the branch and are left untouched.

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Assisted-by: Claude:claude-opus-5 [Claude Code]
The arm64 CPU image failed to build:

  cc1: error: invalid feature modifier 'sme' in
       '-march=armv9.2-a+dotprod+fp16+sve+i8mm+sve2+sme'

ggml's CPU_ALL_VARIANTS table includes armv9.2 variants compiled with +sme, and
Ubuntu Noble's default gcc-13 rejects that feature modifier. Every entry in the
table has to compile even though a host only ever dlopens the one its own CPU
supports, so a single unbuildable variant fails the whole image. gcc-14 accepts
it, which is exactly the fix llama-cpp already carries in
.docker/llama-cpp-compile.sh; this is the same problem reached by a different
Dockerfile.

Applied to every arm64 BUILD_TYPE rather than to the CPU one alone, and that
differs from llama-cpp on purpose. llama-cpp needs it only for its pure-CPU
image because its GPU builds run llama-cpp-fallback, which builds no variant
table. This backend's Makefile turns ENGINE_ENABLE_CPU_ALL_VARIANTS on for
every non-Darwin build, GPU included, so an arm64 GPU image would hit the
identical error. The matrix has no arm64 GPU entry today, which is precisely
why gating on an empty BUILD_TYPE would leave the trap armed for whoever adds
the first one.

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Assisted-by: Claude:claude-opus-5 [Claude Code]
@localai-org-maint-bot
localai-org-maint-bot force-pushed the feat/audio-cpp-native-backend branch from b7ecc1b to b114495 Compare July 28, 2026 08:17
@localai-org-maint-bot

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Picked up and rebased the branch onto current master (366db11c), then force-pushed the updated head as b1144954. The rebase retained master’s vllm.cpp registrations alongside this PR’s audio.cpp registrations in the two overlapping aggregate/gallery locations. git diff --check passes and all 31 backend-filter tests pass. The backend-local make test target confirms its standalone C++ suite is run through the repository-wide make test-backend-cpp; I did not start that long build in this cron run. The prior red jobs were unrelated backend matrix failures (Nemo/Qwen/Kokoro/Sherpa), so the fresh head now has CI restarted from current master.

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Support audio.cpp backend

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