The word "repack" comes from the software piracy scene. A "repack" is a cracked version of software that has been compressed to a smaller size without losing functionality, or re-released to fix previous errors.
This feature is written from the perspective of a tech/music journalist, explaining the phenomenon, the technical reality, and the community surrounding it. 640 kbps songs repack
Most lossy codecs are designed to be "transparent" (indistinguishable from the source) at bitrates between 256 kbps and 320 kbps. The word "repack" comes from the software piracy scene
The "640" file was simply a 320 MP3 that had been transcoded (re-encoded) to a larger file size. The uploader took a 10MB song and turned it into a 20MB song without adding any lost data. You cannot regain frequencies that were permanently removed by lossy compression. Most lossy codecs are designed to be "transparent"
A true high-quality file will show frequencies reaching up to .