Clarify contribution and upstream weight license scopes

README.md

@@ -11,7 +11,22 @@ inference: false
 
 # ACappellaSet models
 
-**Licensing scope:** All 29 model checkpoints use **[CC BY-NC 4.0 — full weight license](licenses/CC-BY-NC-4.0.txt)**, subject to [upstream notices and third-party rights](WEIGHTS_NOTICE.md). The root [LICENSE](LICENSE) applies MIT only to original documentation and metadata; it does not license the model weights. [Source code on GitHub](https://github.com/pting126/ACappellaSet) uses MIT with third-party notices.
+## License scope
+
+| Material | License / Terms |
+| --- | --- |
+| ACappellaSet contributions to the 29 released model checkpoints | CC BY-NC 4.0, to the extent of rights held by the ACappellaSet contributors. See [license text](licenses/CC-BY-NC-4.0.txt). |
+| Embedded third-party pretrained weights and encoders | Subject to applicable upstream terms and permissions. See [WEIGHTS_NOTICE.md](WEIGHTS_NOTICE.md). |
+| Original documentation and metadata | MIT ([LICENSE](LICENSE)) |
+| Original source code | MIT ([GitHub LICENSE](https://github.com/pting126/ACappellaSet/blob/main/LICENSE)), subject to third-party notices. |
+
+**The MIT license does not apply to model weights.**
+
+The CC BY-NC 4.0 designation does not relicense third-party pretrained parameters.
+Redistribution permissions for upstream-derived weights remain subject to verification.
+
+Dataset audio is governed by its separate
+[Dataset Terms](https://huggingface.co/datasets/AcappellaSet/ACappellaSet).
 
 Model weights and release metadata for a cappella source separation.
 
@@ -93,7 +108,7 @@ Validation-selected models record the validation corpus, shared/inclusive scope,
 ## Licenses and citation
 
 Original repository documentation and metadata use the [MIT license](LICENSE), which does not apply to model weights.
-All 29 model checkpoints use [CC BY-NC 4.0](licenses/CC-BY-NC-4.0.txt). Preserve attribution and indicate changes when sharing. This project license applies only to rights the licensors can grant; upstream notices and third-party rights remain applicable. See [weight notices](WEIGHTS_NOTICE.md). Dataset audio is separate.
+ACappellaSet contributions to the released checkpoints use [CC BY-NC 4.0](licenses/CC-BY-NC-4.0.txt), to the extent of rights held by the contributors. This designation does not relicense embedded third-party pretrained parameters; upstream redistribution permissions remain subject to verification. Preserve attribution and indicate changes when sharing. See [License scope](#license-scope) and [weight notices](WEIGHTS_NOTICE.md). Dataset audio is separate.
 Upstream architecture attribution is maintained in the GitHub repository's
 [third-party notices](https://github.com/pting126/ACappellaSet/blob/main/THIRD_PARTY_NOTICES.md).