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Has anyone ever transcoded music from a high-quality aac to an mp3 (or vice-versa). The internet is full of people who say this should never be done, but apart from the theoretical standpoint that you can only lose information, does it matter in practise?

  • is the difference perceivable, except on studio-equipment?
  • does the re-encoding actually lose much information? If, p.e., high frequences are chopped away by the initial compression, those frequencies aren't there anymore, so this part of the compression-algorithm won't touch the data during the second compression. Am i wrong?
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an interesting answer here: – cipricus May 15 '13 at 9:42
up vote 3 down vote accepted

It'll really depend on what the nature of the audfio, the hearing of the person involved, the gear and both psycological and psycoacoustic models.

Basically different psycoacoustic models discard different types of signals, so you'd lose different things.

I'd avoid it personally, but if you had to do it, you probably have equipment that isn't that great to start with, and you might not notice - I can't tell the difference between flac and 320vbr on most soundcards, or which tracks i may have reconverted in the past.

I've done similar things in the past (downsampling music) and honestly, on most gear, i can't tell the difference. I'd say try it, test it double blind, and in most cases, you wouldn't be able to tell.

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Agreed. I also found the following interesting article, btw.:… – Fabian Zeindl Jun 16 '12 at 9:05

Information will inevitably be lost, but unless you're an audiophile using top-grade equipment, the difference will likely not be noticeable.

Conversion of any data, whether or not it is already in a lossy format, to another format which is lossy, will result in loss of information as the compression algorithms will always discard data from the source data. However, because this operation is being performed across formats with high bit rates, the loss will be fairly limited. For more information, see this Wikipedia article on generation loss.

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