searchi/docs/SPEECH-FINAL-QUALITY.md

Bounded speech and timeline verification

2026-10-14, Windows development VM, CPU only (SEARCHI_FORCE_CPU=1). This closes a focused reassessment of the existing speech implementation; it does not introduce another ASR model or claim perfect speech recognition. Google EmbeddingGemma 2 remains the retrieval model. The pinned local whisper.cpp base model, Silero VAD and DTW supply recognized passages and estimated source positions.

Practical improvement already retained

The previous frozen publisher-timed diagnostic improved strict timestamp-start hits from 4/8 to 6/8 with VAD plus DTW. Both remaining orange-soil queries still missed their passage. See the unchanged comparison. That diagnostic is one English recording with correlated queries, not a current end-to-end hybrid score. It cannot establish word-level precision.

The shipped implementation uses bounded 30-second windows with two-second overlap, source-preserving decoding, speech gating, and sentence locations from first/last token points. It retains errors rather than inventing transcripts. No new timing offsets, label-specific heuristics or larger model were added: the remaining measured misses concern recognized content, and the available evidence does not justify increasing indexing cost merely to move timestamps.

New genuine runtime check

The exact 30-second PCM from the earlier failed long-source service run was retested through the current normal distribution worker, forced onto CPU. The existing Rust integration test copies the runtime and models into genuine Unicode paths, verifies their inventory, transcribes twice, and requires stable, nonempty, bounded passages and zero warm model-loading time.

Measurement	First call	Warm call
Native VAD	97.8375 ms	113.021 ms
Native ASR	47,312.2 ms	48,474.65 ms
Native model loading	235.8515 ms	0 ms
Transport	44.8708 ms	48.6905 ms
CPU fallback	0 ms	0 ms

The test passed in 129.23 seconds including inventory verification, relocation and cleanup. These are indexing timings, not search latency. Successful isolated repetition does not explain or erase the earlier service transport failure, which remains recorded in speech integration. The existing next-source recovery remains in place.

Verified input/artifact	SHA-256
Exact previously failed PCM	03ef72d2a4cb926b7d31fbaef757a6cb954a55d6d6961085ea6992728c8d9e37
Normal speech worker	9c34aa2b12a4c2ab876a1573045ef9a31e19e7dfff76a2b34efdf45555ad97aa
Runtime inventory	98ca365d4a298b23ca240967e005750db83613b09eaa89ed714afb711b42c87d

Reproduction uses crates/searchi-speech/tests/native_cpu.rs, with SEARCHI_TEST_SPEECH_WORKER=.searchi/s-a3/runtime/searchi-speech-worker.exe, the pinned base/Silero files in .searchi/speech/models, and SEARCHI_TEST_SPEECH_PCM=.searchi/speech-runtime/nasa-exact-crash/input.f32:

$env:SEARCHI_FORCE_CPU = '1'
cargo test -p searchi-speech --test native_cpu --locked -- --ignored --nocapture

Actual media source-clock checks

Both real FFmpeg integration tests passed in 3.53 seconds:

• Audio beginning two seconds into a video decodes at its actual source origin; a whole-file decode preserves the preceding silence.
• An internal timestamp gap, bounded seek and final tail preserve exact source sample positions without shifting later speech towards the beginning.

$env:SEARCHI_FORCE_CPU = '1'
$env:SEARCHI_TEST_FFMPEG = 'C:/Users/karl/searchi/.searchi/media-runtime/bin/ffmpeg.exe'
$env:SEARCHI_TEST_FFPROBE = 'C:/Users/karl/searchi/.searchi/media-runtime/bin/ffprobe.exe'
cargo test -p searchi-service --test speech_stream_offset_cpu --locked -- --ignored --nocapture

These checks establish source-clock handling, not recognition accuracy. Speech positions remain estimates; overlapping windows and imperfect transcripts can still produce repeated or incomplete passages. The previously recorded tiny English/German positive retrieval check and music/silence negative recognition controls remain useful evidence, without a new broad media-quality rating.