converting MP3 to AAC
I just converted a bunch of my MP3's to AAC, by going into iTunes header Advanced Convert selection to AAC. But now there are copies of all that music in MP3 and AAC. If I choose consolidate library will that fix that and delete all the MP3 copies of the AAC music? Or do I have to do it one by one, in iTunes folders?
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The bit rate is how much data is being pushed per second. This means a 192kbps MP3 is going to be the same size as a 192kbps AAC file. In fact, converting an MP3 to AAC is probably going to kill the quality somewhat. I mean, you're recompressing something that is already compressed.
It isn't worth it.
Originally posted by M3D Jack
Yeah, basically, here is a primer on it...
The bit rate is how much data is being pushed per second. This means a 192kbps MP3 is going to be the same size as a 192kbps AAC file. In fact, converting an MP3 to AAC is probably going to kill the quality somewhat. I mean, you're recompressing something that is already compressed.
It isn't worth it.
I have converted a lot of 160 and 192bit MP3's to 128 AAC and I can not tell the difference at all. None of my friends can tell and they are quite surprised when I tell them that this is at 128 AAC.
There probably is a loss when converting 160+ to 128 AAC but probably not that much that is noticable. I'm sure that if you converted a 160 MP3 to lets say a 192 AAC then there will probably be a noticable difference in the quality.
If you really want AAC files, which supposedly sound better at smaller sizes than MP3s, compress from the original CD or get AACs from Apple or other sources. If you can't do that, leave your MP3s as they are!
Originally posted by Ringo20000
I'm in the process of re-ripping my cd collection to aac and I have some cd thats i intially ripped to mp3 and then burned as an audio cd onto a cd-r. I'm wondering how much quality I would lose bu re-ripping one of these audio cd's into aac
Going CD -> MP3 -> CD -> AAC should be the same audio wise as going MP3 -> AAC, as in, you will lose sound quality. It's always best to rip from the original CD.
Originally posted by LoCash
I mean, you're recompressing something that is already compressed.
Are we sure that this is what happens? I mean, this is my thinking as well, but...
If the algorithm is to cut off anything above a certain audio frequency and that's done in the initial mp3 ripping, wouldn't re-ripping it do nothing to what was left?
Say that mp3 conversion cuts off frequencies above 20khz (I'm totally making that number up). That part of the audio is now gone. Now say that aac conversion also cuts off that part of the audio. There's nothing to cut there because it was already cut. So there should be no loss of quality.
Again, I'm not sure that this is really how it works, but that's been my understanding of how mp3's compress files. Correct me if I'm wrong. It's happened before.
Of course it could be that the algorithm just calculates what it's going to cut based on what's there. In that case, there would a degradation of quality.
But I would have to agree with the others... there's no advantage to HAVING AAC files, the only advantage is when RIPPING them because you get good quality for less space. If you convert MP3s to AACs, you may as well just reduce the bit rate of all your MP3 music because you'll be removing parts and reducing quality while also reducing the space. I guess if you're REALLY pressed for space then you can go ahead, but otherwise just leave all your music how it was originally ripped.
Torifile, here's a better example (using arbitrary numbers, I don't have a good idea either):
MP3s remove sound above 20 khz and below 20 hz. Then, assume that AACs remove sound above 19.5 khz and below 19 hz. Again, these are arbitrary numbers I made up, but if you had ripped the song directly to AAC it would have a range of 19hz - 19.5 khz whereas the MP3 would have 20 hz - 20 khz. An MP3 converted to AAC would have a range of 20 hz-19.5 khz. Basically, they remove different frequencies, so any overlap will result in the final product of an MP3 -> AAC conversion being simply all the frequencies that are NOT deleted by either one. If they both removed the same frequencies, then they would be the same format, not different formats.
You should really just re-rip from the original CD's, man. I have noticed some loss of? "life" from when I'd recompressed, and it compelled me to just rip them again. Do the right thing. Get your CD's.