Two issues in flush_is_idempotent_and_leaves_clean_state from
581a098:
1. silence_close_samples and max_chunk_samples were cast `as u64`
but with_thresholds takes usize — wouldn't compile.
2. enter_threshold was 0.005 and exit_threshold 0.01, which
violates the hysteresis invariant (enter must be >= exit) and
panics in debug_assert at runtime. Swap to 0.01 / 0.005 so the
test actually runs.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
The earlier audit noted that `flush()` had three exit paths but only two
of them explicitly cleared all state-machine fields:
1. InSpeech with non-empty active_chunk: emit_active_chunk_and_close()
handled it.
2. InSpeech with empty active_chunk (hit_max-mid-flush): handled inline.
3. Idle (no padded frame, or padded frame closed cleanly): no explicit
reset — silent_tail_samples / pending_onset_frames / onset_buffer
could carry stale values from `consume_frame` calls inside the same
flush.
In the worst case, the first feed of a fresh recording could see leftover
onset bookkeeping and produce a chunk start that doesn't match the new
session's audio. Reusing the same `RmsVadChunker` across stop/start is
the main path that would hit this.
Add a single defence-in-depth reset block at the end of flush — every
exit path lands the chunker in the same fields a fresh chunker has,
except `next_sample_index` (the running total-samples counter, intent-
ionally preserved). Test asserts: a second flush after a full speech →
silence → partial-pending sequence emits zero chunks, and a subsequent
silent feed also emits zero, proving no stale state leaked.
(kon-transcription doesn't build in the audit sandbox because ort-sys's
build script can't reach pyke's CDN; CI cross-platform compiles it.)
https://claude.ai/code/session_0189xUb6ie6t9qHkzatGZ9Rb
Auto-applied cargo clippy --fix across 11 files — needless return,
unnecessary cast, map_or simplification, repeat().take() → repeat_n(),
iter().any() → contains(), manual char comparison, lifetime elision,
push_str single-char, reference immediately dereferenced.
Also fixed three lints on file_storage.rs manually: two doc-list-item
overindentations, plus the same needless-return. Baseline main was
not clippy-clean with -D warnings before; after this pass one
needless_range_loop warning remains (live.rs:1089) that clippy's
suggested rewrite would make less readable — left for a dedicated
refactor session.
Build + workspace tests remain green (245 passing, 0 failing, 1
ignored).
CRITICAL from the 2026-04-22 code review: RmsVadChunker::flush() was
calling consume_frame() on a zero-padded final frame via `let _ = ...`,
discarding any VadChunk the call emitted. If the padded frame triggered
end-of-utterance (silent tail + padding zeros push past
silence_close_samples) or max_chunk_samples (buffered speech + padding
push past the cap), the emitted chunk was lost; the outer state check
then either returned None or an empty closing chunk.
Changes the VadChunker trait flush signature from Option<VadChunk> to
Vec<VadChunk> so both the mid-flush emission (from consume_frame) and
the closing emission (from emit_active_chunk_and_close) can be
surfaced. Updates RmsVadChunker::flush to collect from both sites
and skip a zero-length closing emit when the hit_max continue variant
already cleared active_chunk.
Two regression tests land alongside:
- flush_preserves_hit_max_chunk_from_padded_final_frame: tight
max_chunk, sub-frame speech tail; pre-fix dropped the chunk, post-fix
emitted samples cover the full active-speech region.
- flush_preserves_end_of_utterance_chunk_from_padded_final_frame:
silent tail near silence_close; padded zero frame closes the
utterance inside consume_frame; pre-fix returned None.
No production callers yet — the VadChunker wiring in live.rs is a
deferred item from A.3. API change is clean within the repo.
Review feedback (MINOR): the original <= 0.0 clamp caught negatives
and zero but not non-finite inputs. Rust's saturating float-to-int
cast turns f64::INFINITY into u64::MAX, which would park the capture
buffer origin beyond any reachable sample index and trim the whole
buffer forever if a future end_secs source ever produces infinity
(clock glitch, overflow upstream, corrupted timestamp in a pass).
Adds is_finite() check. NaN, +infinity, -infinity, and zero all
return 0, which downstream trim_buffer_to_commit_point treats as
no-op. Test covers all three non-finite cases.
Review feedback (CRITICAL): when a chunk hit max_chunk_samples during
continuous speech, emit_active_chunk reset state to Idle. The next
1-2 loud frames of post-split continued speech went into onset_buffer
and were silently cleared if silence arrived before the 3-frame onset
threshold — 50-100ms of user audio lost at every max-chunk boundary
in long-continuous-speech scenarios.
Splits emit_active_chunk into two variants:
- emit_active_chunk_and_close: the existing behaviour. Used for
end-of-utterance closes and end-of-session flush. Truncates trailing
silence, resets state to Idle.
- emit_active_chunk_continue: mid-utterance split on max_chunk. Stays
in State::InSpeech, clears active_chunk for continued accumulation,
advances active_chunk_start by the emitted length so the next
chunk's start_sample is contiguous with this one's end. No
silence-trim (by definition still in speech — end-of-utterance
takes priority).
Adds max_chunk_split_preserves_audio_contiguity test: feeds 17 frames
of continuous speech into a chunker with a 4-frame cap, asserts
(a) chunk[i+1].start_sample == chunk[i].start_sample + chunk[i].samples.len()
across every pair, and (b) the final emitted region reaches the end
of the fed speech with no sample loss.
Review feedback (CRITICAL): LocalAgreement::push could panic with an
index OOB when a later pass arrived shorter than committed_count.
Concrete case: commit [a, b], next pass arrives [a] — lcp_len=1,
new_committed=max(1, 2)=2, then latest[2..] panicked because
latest.len()==1.
A Whisper re-transcription of an overlapping window can legitimately
collapse repeated segments, or the user can stop mid-utterance after
some tokens were already committed, both of which produce this
shape. The committed_count invariant still holds (non-shrinkage) —
it is the slicing that was unsafe.
Clamps every latest[..] slice against latest.len() before indexing.
committed_count stays at new_committed even when the pass is shorter:
non-shrinkage is relative to what we have already emitted, not to
the current pass length. newly_committed and tentative both return
empty when the shorter pass has nothing past the committed prefix.
Adds two regression tests:
- shorter_pass_after_commit_does_not_panic (commit 2, push 1)
- empty_pass_after_commit_does_not_panic (commit 1, push empty)
New streaming::buffer_trim module with two pure helpers:
- sample_index_for_seconds(end_secs, sample_rate) -> u64: converts
LocalAgreement::last_committed_end_secs() into an absolute sample
index. Defensive against negative end_secs (treats as 0) so a future
clock-skewed timestamp cannot wrap to a huge u64.
- trim_buffer_to_commit_point(buffer, buffer_start_sample,
commit_sample_index) -> new_buffer_start_sample: drains the prefix
of the capture buffer that falls below the commit point and returns
the new absolute-index origin.
Edge cases covered by tests:
- commit before buffer start → no drain
- commit equal to buffer start → no drain
- commit inside buffer → drain prefix, advance origin
- commit at buffer end → drain all, origin moves forward
- commit past buffer end → drain all, origin parks at commit (rare
edge after a committer reset)
- sample_index_for_seconds rounds nearest, negatives clamp to 0
- integration with LocalAgreement::last_committed_end_secs
trim_bounds_buffer_over_long_session is the acceptance fixture for
the ufal #120/#102 failure mode: 100 cycles of 16_000 captured samples
with a 200-sample tentative tail per cycle, and the buffer stays below
2× the tentative envelope instead of growing to 1.6M samples.
Integration into src-tauri/src/commands/live.rs deferred to the
dogfood session that wires VadChunker and LocalAgreement end-to-end —
the trim is a one-line replacement at the maybe_dispatch_chunk drain
site once the committer is feeding it commit points.
New streaming::commit_policy module implementing ufal's
LocalAgreement-n pattern: tokens emitted by the streaming ASR
pipeline stay tentative until N consecutive passes produce the same
prefix, at which point the agreed prefix commits.
Types:
- Token: text + absolute start/end seconds. PartialEq is text-only so
identical words from overlapping Whisper windows compare equal even
when their timestamps drift.
- CommitDecision { newly_committed, tentative }: the partition fed
back to the live-session worker after each pass.
- CommitPolicy enum with LocalAgreement { n }. Default is n=2 (ufal).
- LocalAgreement: stateful committer with push/flush/reset and a
last_committed_end_secs accessor. Brief item #25 uses the latter
to compute the sample-index drain target for aggressive buffer trim.
Invariants exercised by tests:
- first pass is all tentative (need 2 passes to commit under n=2)
- two matching passes commit their common prefix
- divergent second pass commits nothing
- extending agreement commits only the newly-agreed tokens
- tentative tail tracks latest pass only (no stale guesses)
- committed prefix never shrinks, even if later passes contradict
- flush emits any tentative-but-not-committed tail at session end
- flush on empty history is a no-op
- reset clears all commit state
- n=3 requires three matching passes before anything commits
- CommitPolicy::default() is LocalAgreement { n: 2 }
Integration into src-tauri/src/commands/live.rs deferred — the
tentative/committed split needs the B-side 'tentative: bool' field on
LiveResultMessage.segments (workstream-B #24 UI contract) and
validation against real streaming captures before going live.
New crates/transcription/src/streaming/ module with:
- VadChunker trait: Send-bound, object-safe, push/flush/reset/
next_sample_index. Same surface a future Silero backend will
present, so live.rs wiring does not change when Silero drops in.
- VadChunk type: (start_sample: u64, samples: Vec<f32>) for
commit-policy sample-offset bookkeeping in #24.
- RmsVadChunker: fallback backend the plan permits while the
ort 2.0.0-rc.10 vs rc.12 ecosystem conflict blocks silero-vad-rust
/ voice_activity_detector. Tuned to match the existing
evaluate_speech_gate behaviour (enter 0.003, exit 0.0014, 3-frame
onset, 500 ms silence close, 2 s max chunk).
Key behavioural properties, each backed by a test:
- pure silence emits nothing
- samples between exit and enter thresholds never trigger onset
- a single loud frame does not start a chunk (sustained speech only)
- sustained speech followed by silence emits exactly one chunk
- hysteresis: a dip between enter and exit does not split a chunk
- max_chunk_samples caps continuous speech (Whisper never fed > 2 s)
- flush surfaces in-flight speech
- flush on an idle chunker emits nothing
- reset restores a clean state
- emitted chunk start_sample includes the onset buffer (Whisper sees
the speech attack, not post-onset audio)
Open items tracked as follow-ups:
1. Silero backend via direct ort rc.12 bridge (Handy-style). Blocked
on either ecosystem ort alignment or dedicated bridge session.
2. Integration into src-tauri/src/commands/live.rs. Deferred so
threshold tuning can be validated against real microphone
captures rather than synthetic constant-signal fixtures.
