Commit Graph

20 Commits

Author SHA1 Message Date
Ettore Di Giacinto
a5144fd958 fix(audio-cpp): refuse a task pin the RPC cannot serve, and stop empty 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>
2026-07-29 19:05:36 +00:00
Ettore Di Giacinto
71c6564b46 backend(audio-cpp): refuse the unsupported RPCs with a reason
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>
2026-07-29 19:03:33 +00:00
Ettore Di Giacinto
d31e923bb7 backend(audio-cpp): bound the lane a live stream can hold
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>
2026-07-29 19:03:33 +00:00
Ettore Di Giacinto
8da5cde0c0 backend(audio-cpp): serve the AudioTranscriptionLive RPC
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>
2026-07-29 19:03:33 +00:00
Ettore Di Giacinto
356a41e10d backend(audio-cpp): keep streaming deltas on UTF-8 boundaries, refuse dtypes that abort
TranscriptStreamResponse.delta is a proto3 string, whose wire format requires
valid UTF-8. voxtral_realtime reports its hypothesis as a concatenation of raw
token BYTES (tokenizer_text.cpp:171-183), so the cumulative difference between
two consecutive reports is eventually a lone continuation byte, and the C++
runtime serializes that with only a logged warning while the Go runtime refuses
to unmarshal it: the client loses the remaining deltas AND the final_result.
Measured on a trace of a non-ASCII sentence, 11 of 31 messages failed to
unmarshal and every accented character was lost. TranscriptDeltaTracker now
holds back an incomplete trailing sequence and merges it into the next fragment;
reconcile flushes it, which it always can because the final text is complete.
The same trace now unmarshals in full with zero failures.

A streaming buffer whose float count is not a whole number of frames is refused
rather than truncated. The integer division dropped the tail floats from the fed
audio and therefore from the transcript, with no diagnostic; vibevoice_asr
refuses the same thing from the other side of the call.

A supertonic GGUF whose weights are not f32 is refused at load. It reaches
ggml_concat with mismatched operand types and ggml_abort takes the whole backend
process down on the first request, so nothing downstream can report it: the
model loads, then every request kills the process. Attributed rather than
assumed, the unary TTS path aborts identically, and upstream records that
package as untested. The refusal names the orig package and says what to run
before deleting the guard.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
2026-07-29 19:03:33 +00:00
Ettore Di Giacinto
a996d7dd23 backend(audio-cpp): serve the TTSStream and AudioTranscriptionStream RPCs
TTSStream leads with a streaming WAV header carrying 0xFFFFFFFF sizes, matching
the convention backend/go/vibevoice-cpp established, so an HTTP client can start
playback before the full PCM exists. Its chunks are read from
StreamEvent::named_audio_outputs and not audio_output: supertonic, omnivoice and
voxcpm2 all put their streamed audio there and leave audio_output empty until
the very end, so reading the obvious field yields a stream with no audio in it.
The finish_stream result is the family's own merged whole rather than a tail, so
it is emitted only when nothing was streamed.

Streaming transcription sends incremental deltas and degrades to a single delta
plus the final result on families that offer no streaming ASR, which is the same
message sequence with fewer deltas. The four streaming ASR families disagree on
what partial_text means: nemotron_asr, vibevoice_asr and higgs_audio_stt report
incremental fragments while voxtral_realtime reports the whole hypothesis and
reports it twice, so the reconciliation lives in one tested unit rather than in
the handler. nemotron_asr reports only through the stream event sink, and only
from inside finalize, so the audio driver installs one and clears it again
before returning: the session is cached and a sink left holding the caller's
frame is a use after free waiting for the next stream.

begin_stream is now the only implementation of the streaming state obligation,
prepare then start_stream. Streaming sessions are cached, and what clears the
previous stream is start_stream's reset; a family override that dropped it would
break every call site with no compile error, so there is one call site.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
2026-07-29 19:03:33 +00:00
Ettore Di Giacinto
ca6303171a backend(audio-cpp): stop emitting an empty style language, and name the missing clip
StyleCondition::language was set whenever has_language() was true, with no
!empty() guard, while the language option twelve lines below had one.
core/backend/tts.go sets Language unconditionally, so has_language() is true on
every request LocalAI sends and carries "" when the caller named none. An
engaged-but-empty style language is worse than an absent one: supertonic reads
text_input->language behind its own !empty() guard and then overrides it from
style->language with no guard at all, so "" replaced its "en" default and its
tokenizer threw "invalid Supertonic language: ". Every /v1/audio/speech request
that set instructions and no language would have been an INTERNAL against a
supertonic model. A plain request never saw it, because the style condition only
exists when instructions are non-empty, which is why the chatterbox end to end
run did not catch it.

TTS also stops discarding the Route that check_can_serve already returns. A
family routed to voice cloning without a reference clip used to be refused from
inside its own prepare(), which meant an INTERNAL naming neither the RPC nor the
field to set; chatterbox advertises clon and no tts, so that was every
preset-only request to it. It is now an INVALID_ARGUMENT naming
TTSRequest.voice, answered in about 4 ms, and it cannot misfire because
has_voice_reference is what selected cloning in the first place. Reading
CapabilitySet::supports_speaker_reference to generalise this stays a follow-up.

The src read carries a written caveat rather than a family blocklist, because
ace_step's editing routes legitimately need src: setting src on a stable_audio
model corrupts the heap and aborts the process in the pinned upstream, and the
only thing keeping that off the network is that
schema.ElevenLabsSoundGenerationRequest has no field for it. Nobody reading that
Go schema would know why, so the reason is recorded where the field is read.

build_tts_shape is extracted so TTSStream cannot describe the same request
differently, and it arrived untested: two mutations of it survived until a
test_tts_shape case was added.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
2026-07-29 19:03:33 +00:00
Ettore Di Giacinto
d318b2ea94 backend(audio-cpp): serve the TTS and SoundGeneration RPCs
TTSRequest.voice is treated as a speaker reference clip when it names an
existing regular file, which makes routing prefer VoiceCloning, and as a named
preset otherwise, in which case it travels as VoiceReference::cached_voice_id.
Both the clip and SoundGenerationRequest.src are read at the file's own rate and
channel count: upstream's own CLI and server do exactly that, every consuming
family resamples internally and mostly with a better resampler than ours, and
ace_step and stable_audio resample their input per channel, so a downmix here
would delete the stereo image they are built to consume.

The request builders live in their own unit rather than in grpc-server.cpp's
anonymous namespace so they can be tested; grpc-server.cpp has a main() and
cannot be linked into a test binary. The option keys are the whole point of
these functions, so each one was grepped against the pinned upstream and the
accounting is written down beside it. instructions maps to "instruct", which is
what upstream's own server maps the OpenAI field to and what qwen3_tts and
omnivoice read, and to "caption" for irodori_tts; the style tag is spelled
"instruct" too, because "instructions" is looked up nowhere. duration maps to
"duration_seconds", read by all three generation families, with the proto's own
name kept only as a forward-tolerant alias. Keys that no family reads say so.

Both handlers answer a capability refusal before taking the lane and before any
file read, so a model that cannot synthesise does not queue behind somebody
else's run to be told no.

Assisted-by: Claude:claude-opus-5 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
2026-07-29 19:03:33 +00:00
Ettore Di Giacinto
dc0ac45c5c feat(audio-transform): stop folding every upload to 16 kHz mono, and 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>
2026-07-29 19:03:33 +00:00
Ettore Di Giacinto
b92eff90f1 backend(audio-cpp): refuse an impossible stem early, and stop blaming 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>
2026-07-29 19:03:33 +00:00
Ettore Di Giacinto
6170e03f1b backend(audio-cpp): serve the AudioTransform RPC
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>
2026-07-29 19:03:33 +00:00
Ettore Di Giacinto
7ce4b36837 backend(audio-cpp): fix the segment text a transcription response is 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>
2026-07-29 19:03:33 +00:00
Ettore Di Giacinto
8d6cd6149a backend(audio-cpp): serve the AudioTranscription RPC
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>
2026-07-29 19:03:32 +00:00
Ettore Di Giacinto
ce63363e4d backend(audio-cpp): make the lane and identity guards structural
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>
2026-07-29 19:03:32 +00:00
Ettore Di Giacinto
ae059ab897 backend(audio-cpp): enforce ModelIdentity on VAD and Diarize
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>
2026-07-29 19:03:32 +00:00
Ettore Di Giacinto
fe70b21139 backend(audio-cpp): serve the VAD and Diarize RPCs
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>
2026-07-29 19:03:32 +00:00
Ettore Di Giacinto
e2cad2bf3d backend(audio-cpp): correct the status, lifetime and state contracts 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>
2026-07-29 19:03:32 +00:00
Ettore Di Giacinto
b4153fc6eb backend(audio-cpp): stop aborting the process on SIGTERM
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>
2026-07-29 19:03:32 +00:00
Ettore Di Giacinto
487a2a3dc8 backend(audio-cpp): load models and cache sessions per task
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>
2026-07-29 19:03:32 +00:00
Ettore Di Giacinto
9fdf61553e backend(audio-cpp): add the native build scaffold
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>
2026-07-29 19:03:32 +00:00