A/B test 2026-04-29 across mit_2024intro / mcc / carlini manifests
showed the binary peak threshold (≤ -3 dBFS = +0.5) failed to
differentiate hot clips against each other: an mcc clip with input
peak=-1.47 dBFS scored same as one at -3.5 dBFS, and the model output
tracked input amplitude.
Replace with a linear penalty: 0.5 at peak ≤ -9 dBFS, ramping to 0 at
peak = 0 dBFS, clamped. mcc spk0 now produces graduated scores
(1.63 / 1.58 / 1.56 / 1.51) instead of a 1.5 plateau, reordering the
top selection toward the cleaner-peak clip.
Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>
scripts/pick_context.sh ranks manifest clips by suitability for CSM-1B's
--context-wav conditioning (duration sweet spot 10-13.5s, RMS -25 to
-15 dB, peak ≤ -3 dBFS) and groups by (manifest_stem, speaker_id) since
diarizer labels are per-file.
examples/generate.rs now accepts repeatable --context-wav and
--context-text pairs, zipped into Vec<Segment> for Generator::generate.
Validates equal counts at runtime.
Smoke-tested with two 10-13s spk0 clips from the MIT-2024 manifest.
Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>
