8-gen bench (4 emotions × 2 corpora) at seed=42 against firdhokk
Whisper-LV3:
target RAVDESS CREMA-D
happy happy (0.999) ✓ happy (0.999) ✓
angry neutral (0.92) sad (0.99)
fearful happy (0.998) fearful (0.984) ✓
sad angry (0.99) fearful (0.99)
CREMA-D 2/4 vs RAVDESS 1/4. Larger / more naturalistic corpus
produces more class-pure fearful direction. Neither corpus solves
angry or sad — recipe shifts into 'vague expressivity' rather than
class-specific corners.
Practical: prefer CREMA-D when available; A/B both per emotion if
class precision matters.
Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>
End-to-end SilentCipher: bit-perfect round-trip on real LibriSpeech
audio. Sesame's actual production watermarker now works in pure
candle 0.9 + Metal.
New components in src/silentcipher.rs:
detect(samples_16k) -> DetectResult
1. RMS-normalize to VCTK baseline (matches embed pre-conditioning)
2. STFT -> magnitude
3. dec_m_0(magnitude) -> (B, message_dim, 1, T) logits
4. argmax along message_dim -> (T,) per-frame predictions
5. Truncate to multiple of message_len
6. Reshape to (n_patches, message_len), per-column mode
7. Find terminator (value 0), rotate so payload follows it
8. Subtract +1 offset -> original codes
encode_bits / decode_bits (Phase 10.4 fix)
Switched from base-4 (2 bits per code) to base-`(message_dim - 1)`.
The 16 kHz model has message_dim=4 = 3 carrier values (1,2,3) +
terminator (0), NOT 4 carrier values. Original base-4 packing
occasionally produced value 3, which Python's
`np.identity(4)[index+1]` would have crashed on. Real capacity:
15 codes x log2(3) ~= 23.78 bits per patch.
SilentCipherWatermark (impl Watermarker)
Wraps a SilentCipherWatermarker with a fixed default_payload so
it satisfies the existing Watermarker trait. Maps confidence ->
DetectionResult.mean_presence and the lower-16-bits of the
decoded payload -> DetectionResult.message (None below confidence
0.7 to suppress false positives).
examples/silentcipher_apply
Mirrors audioseal_apply: --in / --out / --payload / --detect-only.
Loads from sony/silentcipher HF repo, embeds, optionally
resamples back to source rate, optionally re-detects to verify.
Verified end-to-end (LibriSpeech /tmp/asr_test.flac, 10.42 s @ 16 kHz):
Build: 29 ms (3 .ckpt files from HF cache)
Embed: 1213 ms = 0.116x realtime
Detect: 1838 ms = 0.18x realtime
payload: 0x00BC614E (in)
recovered: 0x00BC614E (out)
codes match: 15 / 15
confidence: 1.0000
Clean (un-watermarked) audio: confidence 0.475, codes mostly 0 -
strong signal-vs-noise discrimination at the 0.7 threshold.
This closes the most surprising gap from the Sesame stack analysis:
rtx-csm now has the *literal* Sesame watermarker (not Meta's
AudioSeal) working in pure candle. AudioSeal stays available for
callers that prefer it.
Phase 10.5 (next): wire as a third option in converse_server alongside
AudioSeal, and a 24/16 kHz ResampledWatermarker for the CSM path.
Plus an A/B bench (SilentCipher vs AudioSeal).
Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>
