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macgeek77

macrumors regular
Original poster
May 24, 2006
153
0
I have a question about the quality of my media. For the songs I have imported from CD's, I simply put them in the computer, and pressed import? The songs sound great, but is the quality really good, medium, or poor compared to what it could be? How about iTunes songs downloaded from the iTunes store? What is their quality like? Finally, how about movies/tv shows I download from iTunes. What quality are they. Thanks for any help.
 

mzd

macrumors 6502a
Jul 25, 2005
951
41
Wisconsin
the default for iTunes music is 128kbs AAC (mpeg 4 audio) and that is also the format most music purchased from the iTunes store. with the exception of iTunes Plus songs which are 256kbs AAC.
in my opinion, 128kbs is decent quality. mpeg 4 is a better compression than mp3 so you are getting better quality music, bit rate for bit rate.

i personally used to import at 160 VBR AAC but as i only have a 20GB iPod, i switched down to 128 VBR AAC to conserve some space. i found 160 VBR AAC to be equivalent to 192kbs mp3, which i consider to be very good quality.
but depending on your hearing and desired use of the music, that may or may not be acceptable quality to you.

i have no idea on movies/tv shows since i'm not as familiar with video codecs.
 

Mac-Xpert

macrumors 6502
Dec 18, 2003
308
0
The Netherlands
I did find a little difference

I agree mostly with what "Mzd" said above. However, I did a test once and I did find a subtle difference in audio quality between 128kbs AAC and 160kbs AAC/192kbs mp3.

I had one song that had a classic analog synthesizer square lead solo in it. And this synthesizer sound had a little bit of harmonic distortion in it. So this wasn't a "perfect" square wave like you might get from a digital synthesizer.

This distortion (its very subtle) could be heard on the original CD and Vinyl record (that I also have) and also on the 160kbs AAC and 192kbs mp3 files.

On the 128kbs files however, the waveform apparently was altered in such a way that the subtle distortion (that actually gives a certain "analog feel" to the sound) was gone. The sound now sounded like it was created on a digital synthesizer.

That was the only time I could clearly hear a difference between a 128kbs and 160kbs AAC files. On other songs I could only hear a very slight reduction in the stereo field on the 128kbs files and maybe a little less dynamics but not much else.

So if you want to be sure that your AAC files sound virtually identical to the original CD you should stick with 160kbs AAC or 192kbs mp3
 
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