Open video-to-audio (AI foley) models differ mainly by licence: MMAudio weights are non-commercial, HunyuanVideo-Foley excludes the EU/UK/South Korea, ThinkSound is listed Apache-2.0 - check before adding sound to client work

For adding synchronized sound effects to silent generated clips (many video models still output silent video or weak foley), three widely used open V2A models carry very different rights: MMAudio - code MIT, but "the checkpoints are licensed under CC BY-NC 4.0 and can be used for non-commercial purposes only" (R1); HunyuanVideo-Foley - Tencent Hunyuan Community License, which "DOES NOT APPLY IN THE EUROPEAN UNION, UNITED KINGDOM AND SOUTH KOREA" (R2; same family of terms as other Hunyuan releases, C3-B460-01); ThinkSound - Hugging Face metadata lists apache-2.0 (R3; GitHub licence field unset, so confirm the LICENSE file). Research direction (R4-R6): WorldSonus adds real-time (real-time factor 0.41), prompt-steerable, stereo spatial audio to interactive world models via streaming causal diffusion - relevant to the silent outputs of world models (C3-B482-01, C3-B483-01); SCR-V2A conditions on localized sound-producing regions (contacts, object-part motion) to improve fine sync; a Sept 2026 survey taxonomizes joint/cross-modal audio-video generation and 28 joint edit types. Practical: for commercial deliverables pick a permissively licensed or commercial-terms model (and check territory), keep human foley/library SFX for hero moments, and treat NC checkpoints as previs-only. Curator correction 2026-10-24 (discovery audit record C3-B1037-05, curator-reviewed C3R-0686; excerpts re-located by independent curator GET 2026-10-24): Correction. C3-B492-01 (captured about 2026-10-23) listed ThinkSound as "apache-2.0" among options for commercial deliverables; the README (fetched 2026-10-24) opens with "This project is released under the Apache 2.0 License." and then states the restriction below. Not legal advice. That record presents ThinkSound as "listed Apache-2.0" among options for commercial deliverables and says to confirm the LICENSE file. The project README states: "The code, models, and dataset are for research and educational purposes only. Commercial use is NOT permitted. For commercial licensing, please contact the authors." It also says the bundled Stable Audio Open VAE needs "prior permission from Stability AI" for commercial use and redistribution. The Hugging Face metadata does list apache-2.0 (checked 2026-10-24), so two statements conflict: the metadata licence tag and the README note; the README note is the more restrictive. The README sentence "Commercial use is NOT permitted" is present at each of the 20 commits in the repository Atom feed ( 2025-07-03 to 2026-03-24, latest commit 2026-03-24), so by inference the note predates the record's capture by months and the record was wrong as written, not made stale by a later change (older commits not read). The record did say the licence came from Hugging Face metadata only (last modified 2025-07-17) and to confirm the LICENSE file, but still listed ThinkSound as a licensing option for commercial work. Also, the same record's cross-reference to C3-B460-01 should not be read as implying Hy-Nomas shares the territory-excluding terms: the Hy-Nomas model card lists apache-2.0 (checked 2026-10-24). MMAudio (CC-BY-NC checkpoints) and HunyuanVideo-Foley (licence excludes EU, UK, South Korea) statements in the record were re-confirmed. Curator qualifications: All cited documentation excerpts located on the live pages by curator GET; no video sources. Quality of the models not compared; one licence taken from model-hub metadata only. Not legal advice. Limitations: ThinkSound licence from HF metadata only; quality of models not compared; commercial V2A services (e.g. ElevenLabs SFX, Kling/Seedance native audio) not covered here; papers read at abstract level. Evidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.

{
  "citations": [
    {
      "url": "https://huggingface.co/hkchengrex/MMAudio",
      "note": "README; header; abstract"
    },
    {
      "url": "https://huggingface.co/tencent/HunyuanVideo-Foley/raw/main/LICENSE",
      "note": "README; header; abstract"
    },
    {
      "url": "https://arxiv.org/abs/2610.08760",
      "note": "README; header; abstract"
    }
  ]
}