CC BY-SA, LGPL and GPL are all copyleft licenses. GPL's key feature is that by embedding one work in another (as defined in a software context), the combined work becomes GPL. With LGPL this is not the case.

My understanding is that if I embed a CC BY-SA work in something, say a photo in an article or a song in the background of a video, the work does not have to be CC BY-SA, it could even be restricted (as long as attribution is given). So in this way would it be more accurate to compare CC BY-SA to LGPL rather than GPL?

(I assume that a music video of a pre-existing song would be a derived work, but a slideshow with background music would be a combined work. For the purpose of this question let's assume the distinction is clear.)

1 Answer 1


My understanding is that if I embed a CC BY SA work in something, say a [...] song in the background of a video, the work does not have to be CC BY SA

I think this may be a misunderstanding. Looking at CC-BY-SA 4.0, it says in s1a

For purposes of this Public License, where the Licensed Material is a musical work, performance, or sound recording, Adapted Material is always produced where the Licensed Material is synched in timed relation with a moving image.

and in s3b

if You Share Adapted Material You produce, the following conditions also apply [...] The Adapter’s License You apply must be a Creative Commons license with the same License Elements, this version or later, or a BY-SA Compatible License.

So it seems pretty clear to me that according to Creative Commons, if you embed a CC-BY-SA song in a video, the video must indeed be licenced CC-BY-SA (or under a compatible licence). I can't comment on the photo issue.

What this really comes down to is what makes a derivative work, and (as writings here and elsewhere attest) this is not a settled issue. But the distinction is one of copyright law, and not of an explicit exemption (as is the case in LGPL). So for the purpose of this question I regard CC-BY-SA as much more like the GPL, on that basis.

  • But for the other example (embedding a CC-BY-SA photo in an article) I do not think the SA clause applies to the article. This is in fact similar to the LGPL.
    – amon
    Apr 8, 2018 at 13:23
  • 1
    The CC-BY-SA clause is not explicit about whether photo-in-article leads to a derived work, but it is still clear that if it does, the derived work must be CC-BY-SA (or compatible). Whether that leads to a derived work is a copyright law question, not an explicit exemption one; I stand by my conclusion that this is GPL-like, rather than LGPL-like. But you should of course feel free to write your own answer if you disagree.
    – MadHatter
    Apr 8, 2018 at 15:49

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