[ambush]

So I'm running out of space both on my iPod and on my HD. I was considering reencoding all my MP3s (mostly 192-256kbps ****) to AAC.

Is this reencoding lossless? I mean, will I lose quality? I want to KEEP the same quality and REDUCE the space the song takes.. is this possible??

Thanks.

[Developer]

Originally posted by ambush:
Is this reencoding lossless?

No, it's lossy. Whether it's acceptable for your needs, you have to try for yourself. I would be better to directly re-rip as AAC for sure.

[wataru]

This question is asked all the time. Do a search and you'll find that it's very hard to find anyone that recommends you transcode. If you really want to go AAC, re-rip from CDs. For files that you don't have a CD of, leave them as they are.

[ambush]

This is bad.. seeing as MP3->AAC *non-lossy* is physically possible....

[Developer]

Originally posted by ambush:
This is bad.. seeing as MP3->AAC *non-lossy* is physically possible....

Too bad you're the only person who knows how to do this. And you don't code.

[Kenneth]

I re-rip all my collection to AAC (160k) from CD. Too bad, some of the CDs were scratched. I did it over the summer. Depends on how many CDs you own, it will take some times.

[Moonray]

Get a new HD and don't store songs on your iPod to which you won't listen in six months.

-

[Spheric Harlot]

Originally posted by ambush:
This is bad.. seeing as MP3->AAC *non-lossy* is physically possible....

If you can explain how to do this, don't walk - RUN to your patent office and make a million.

Both mp3 AND aac reduce the size or audio files in part by using psychoacoustic profiles to remove aspects of the music that aren't as easily heard because they're "masked" by other sounds (for example, a soft note played in the background will not be as noticeable when a loud note is played in the foreground at the same time - though not inaudible - and the signal will be simplified, reducing the size of the file. This is why busy music will sound a lot worse at the same bitrate than slow music.) . Since mp3 and aac do this using *different* algorithms, making an aac OF an mp3 will sound like ****.

Basically: let's say an mp3 removes 70% of the audio data by using a certain mechanism. When you convert to aac, which removes 70% of the audio data vi a DIFFERENT mechanism, you're not adding anything back, even if an aac of the same source will sound better than the mp3 FROM THE SAME SOURCE - since what the mp3 compression removed from the sound is GONE. Irretrievably. If it weren't, it would sound as good as the source material, which it certainly doesn't.

All you do by converting mp3 to aac is to remove additional information from the already-castrated mp3 audio, due to the different reduction process used by aac and the fact that it cannot add anything back into the sound (that belongs there. There are artifacts and distrortion that you can hear, but that do not belong in the music).

-s*

[philm]

One disadvantage of AAC is that MP3 is so universal. I wanted to burn a CD for my car CD player which handles MP3 files and I couldn't think why it would not play some of the albums - the more recent iTunes imports were AAC by default of course, so my car CD player could not handle those.

I have a new phone which has an MP3 player etc etc.

For me, I am happy to take the exta 20% of hard disk space required for MP3 in return for it being a more usable file format. At present at least.

[mitchell_pgh]

I try to keep everything in MP3. My main reason is... what if I get something that plays MP3 CDs?

When you try to make an MP3 CD in iTunes, all of your AAC songs will be left out.

[mitchell_pgh]

I also try to keep only 160+kb/s MP3s... to compensate for the lower quality.

[pcp_ip]

If you plan on using any external equipment to play your library (TiVo with HMO, Audiotron, etc) you'll be out of luck. Very few third party players support AAC at this point.

[dreilly1]

I keep my songs in MP3 format whenever possible, mostly because I listen to my music on other platforms without Apple Store support.

But I've translated albums from AAC to MP3, and they don't sound as bad as I thought they would. If there's more artifacts in the file than there normally would be, I can't hear them through my headphones.

(After I buy an album on iTunes, I immediately write a CD to archive, and then I rip my CD in my Linux box. Now I have my pick of formats...)

There's no reason why using iTunes to transcode directly without ripping a CD would be any different -- it probably decompresses the original song and immediatly compresses the copy, and just skips the CD middleman.

Why don't you try it with your songs and let us know how it goes? If it sounds OK to you, that's all that matters.
You can always archive your old music to CD-R or DVD-R so you'll still have access to it, even if you delete the songs from your HD.

[legacyb4]

Wouldn't this only apply to ITMS-bought music? If not, then you are only limited by Quicktime, iTunes, and/or AAC-support from other applications on the other platforms.

I'm under the impression that 'Ambush' either has/had access to original CDs that he could rip from. Last year, I went from MP3 to AAC at smaller bitrates (generally 192 => 128) but did backup all my MP3 files on CD/DVD in case I ever wanted to go back.

Cheers.

Originally posted by dreilly1:
I keep my songs in MP3 format whenever possible, mostly because I listen to my music on other platforms without Apple Store support.

[dreilly1]

Originally posted by legacyb4:
Wouldn't this only apply to ITMS-bought music? If not, then you are only limited by Quicktime, iTunes, and/or AAC-support from other applications on the other platforms.

True. The real issue is that I can't be bothered to figure out how to use AAC on Linux or Solaris, which are the other platforms I use. I think Linux has a Quicktime port, but I don't see the Solaris port coming anytime soon, and that's what I use at work.