Foundation for porting Sesame's actual production watermarker (NOT
AudioSeal — the gap analysis identified this as the literal Sesame
parity item). Same iterative-shipping pattern as Phase 8.4 for
Moonshine.
`docs/silentcipher_port_notes.md`:
- Full architecture from SesameAILabs/silentcipher/src/.../model.py
(verified against 95 LOC of source)
- Three small networks of gated 2D convs on STFT:
enc_c 3 layers 1 -> 32 channels
dec_c 4 layers 96 -> 1 channels
dec_m 10 layers 1 -> 128 -> message_dim, plus Linear
- Each Layer = Conv2d * sigmoid(Conv2d) + BatchNorm2d
- Pipeline (encode + decode) walked through step by step
- 10 ordered porting tasks with hour estimates totaling ~1-2 days
- Risks flagged: STFT helper needed, BatchNorm running stats loading,
phase passthrough, message-length differences vs AudioSeal
`examples/silentcipher_inspect`:
- Downloads sony/silentcipher 16 kHz checkpoint from HuggingFace
- Dumps hparams.yaml + tensor shapes per .ckpt file
- Verified output:
N_FFT 2048 HOP 1024 SR 16000
message_dim 4 message_len 16 message_band 512
enc_c 0.17 MB 40 k params
dec_c 2.01 MB 500 k params
dec_m_0 9.54 MB 2.38 M params
Total ~2.92 M params
That's ~10x smaller than AudioSeal's gen+det combined. Port
estimated 1-2 days.
`.ckpt` files are pickle (PyTorch state_dict) — direct loadable via
candle_core::pickle::read_all, same path as audioseal_convert.rs.
No safetensors conversion needed.
Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>
