I have a .mp3 file licensed under CC-BY-ND 4.0 and I want to reencode it (without changing the content within) in the Ogg Vorbis format for sharing, but I do not want to violate the CC license.

1 Answer 1


CC BY-ND 4.0 says in section 2(a)(4):

Media and formats; technical modifications allowed. The Licensor authorizes You to exercise the Licensed Rights in all media and formats whether now known or hereafter created, and to make technical modifications necessary to do so. The Licensor waives and/or agrees not to assert any right or authority to forbid You from making technical modifications necessary to exercise the Licensed Rights, including technical modifications necessary to circumvent Effective Technological Measures. For purposes of this Public License, simply making modifications authorized by this Section 2(a)(4) never produces Adapted Material.

The intent here is quite clear: the ND limitation against producing adaptations does not extend to modifications made purely to prepare the work unaltered in a new technical format. A transformation from MP3 to Ogg seems to match the intent of this section perfectly.

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    Not a legal response here, but 'reasonableness' would suggest that if it sounds the same to most people, then it is the same. I seriously doubt anyone could listen to some music and say "oh wait! That's not the MP3 version!". One aspect of CC content is that it's generally friendly, so you could potentially even ask the original author if it's okay. They might even do the encoding for you from the original source audio (if such a thing exists). Nov 7, 2017 at 16:23
  • @Ralph I agree, and I almost included an aside about re-encoding being a lossy operation (but ultimately decided just to give a simple answer to a straightforward question). I do find it interesting that there might be a point of lossiness at which the work might become a derivative!
    – apsillers
    Nov 7, 2017 at 17:44
  • I forget which, but years ago a dance music act sampled a line from another song. The lawyers got involved, and aside from whatever financial arrangements that may have been agreed, the dance track had to use a horribly down-sampled rendition - think 16k MP3 or so. So yes, it's possible sufficient down-sampling might be considered 'derivative', although "if it walks like a duck, sounds like a duck..." Nov 14, 2017 at 19:28

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