Using the checkpoints from the README's Google Drive links, inference.py returns the same output for every input (real or AI-generated):
Prediction Real | Confidence 98.90% | Fake 0.0110 | Real 0.9890
I traced each stage: inputs differ, backbone embeddings differ (mean abs diff ≈ 0.32), but Stage-2 collapses both to a bit-identical logit −7.2109375 → clamped to 98.90%. Stage-2 isn't dead, random embeddings give varied positive logits; it only collapses on this backbone's embeddings. Ruled out segmentation, fp16/fp32 (margin ~0.0004), loading, and embedding convention.
Likely cause: Stage-2 is trained on precomputed embeddings (is_emb=True) from one specific backbone, so the Stage-1/Stage-2 pair must match. The best_model_path baked into the checkpoints shows they don't line up with the working HF Space:
|
This repo (Google Drive) |
HF Space |
| Stage-1 |
step=075000…val_acc=0.9952 |
step=003432…val_acc=0.9963 |
| Stage-2 |
…2class-epoch=0001…0.9987 (paperver) |
…2class_weighted-epoch=0014…0.9993 |
Could you publish the matched backbone whose embeddings Stage-2 was trained on (the Space's step=003432…), open mippia/FST-checkpoints (currently private/404), or confirm which Stage-1 pairs with the released Stage-2? A working pair should send an AI clip to a positive (Fake) logit instead of collapsing to −7.2.
Using the checkpoints from the README's Google Drive links, inference.py returns the same output for every input (real or AI-generated):
Prediction Real | Confidence 98.90% | Fake 0.0110 | Real 0.9890
I traced each stage: inputs differ, backbone embeddings differ (mean abs diff ≈ 0.32), but Stage-2 collapses both to a bit-identical logit −7.2109375 → clamped to 98.90%. Stage-2 isn't dead, random embeddings give varied positive logits; it only collapses on this backbone's embeddings. Ruled out segmentation, fp16/fp32 (margin ~0.0004), loading, and embedding convention.
Likely cause: Stage-2 is trained on precomputed embeddings (is_emb=True) from one specific backbone, so the Stage-1/Stage-2 pair must match. The best_model_path baked into the checkpoints shows they don't line up with the working HF Space:
step=075000…val_acc=0.9952step=003432…val_acc=0.9963…2class-epoch=0001…0.9987(paperver)…2class_weighted-epoch=0014…0.9993Could you publish the matched backbone whose embeddings Stage-2 was trained on (the Space's step=003432…), open mippia/FST-checkpoints (currently private/404), or confirm which Stage-1 pairs with the released Stage-2? A working pair should send an AI clip to a positive (Fake) logit instead of collapsing to −7.2.