If the user attempts to convert the 640 kbps file to FLAC to "upgrade" quality:
Don't chase the number. Chase the source. A proper FLAC rip of a specific CD pressing (with a specific barcode) is worth infinitely more than 10,000 mislabeled "640kbps repacks." 640 kbps songs repack
A repack implies the files were previously released in a different format (e.g., FLAC → 640 kbps AAC) or reorganized for better metadata, tagging, or error correction. Repacks often fix: If the user attempts to convert the 640
: For most listeners, even with professional gear, it is nearly impossible to distinguish between a genuine 320 kbps file and a higher-bitrate file or even a lossless FLAC. Why "Repacks" Exist Repacks often fix: : For most listeners, even
If you are a collector with a moderate DAC (like a DragonFly Cobalt or Qudelix 5K) and good headphones (Sennheiser HD600 or better), a genuine 640 kbps AAC repack from a lossless source is the sweet spot of quality vs. file size.
Most of these are "transcodes." If someone takes a 320 kbps file and re-saves it at 640 kbps, the quality doesn't go up—the file size just gets bigger while the audio actually degrades slightly due to re-compression.