Thanks Bryan, this day was surely a great learning experience for me, and i am not quite sure how i shall process it all, but I shall have recourse to the stuff and that is a help. - No. I am not finished with my questions as yet. When i open the iTunes preferences and click on burning, I have two options : it says : preferred speed - then Audio CD, then MP# 3 CD and sound check in between and then comes Data CD or DVD and that tells me that this might not play on all players. Now: if I click the audio CD ( being AAC standard if it is music I bought from the music store, and AIFF if I imported it myself if that is the standard Apple uses in outside the music store bought CDs because it would not embed the DRM?) I can have a gap between the songs which apparently I cannot have if I choose the MP# format, the songs running together in that format without a pause. Am I correct here? And what does it do when I check "sound check" ? Who checks what sound and how do I know according to which criteria the sound is checked? Of course when I import now I have the possibility to choose the format which I did not know a year ago, so I actually cannot tell anymore now what format all my songs and operas etc were imported in, because as a fledgling I knew little about the preferences and would not have known even if I opened the preference panel. To repeat : if I check the output as Audio CD, will my CD then be in the AIFF format unless I choose the MP3 format ? Is there a way to check the format a CD is in at all? By trial and error - meaning taking it to a player somewhere and see whether it plays? Or something more professional? Marta On Jan 24, 2005, at 20:18, Bryan Forrest wrote:
> Ok, I know others have already answered this, but I spent a good 20 > minutes working on it earlier, and I'm gonna send it anyway... so > there! :-p > > > > The AIFF (Audio Interchange File Format) is the default format Apple > uses to read audio files from regular music CDs, i.e., the kind you > would play in your stereo. These files typically run about 10-12MB per > minute of audio. So a typical 3.5 minute song would be about 35-40MB. > > MP3 (Mpeg Layer 3) is the most common form of audio file on the > internet. The MP3 compression algorithm allows the 35-40MB AIFF (or > WAV for Windows) file to be compressed to about 1/10th its original > size (allowing for standard settings of 44.1Khz/128Kbps). > > Apple's current standard is AAC (Advanced Audio Codec). This is the > format that is sold via the iTunes Music Store. It provides higher > quality audio than MP3 at approximately the same size. In addition, > Apple is able to embed its DRM, or Digital Rights Management, key into > each audio track, to prevent unauthorized copying of purchased music. > AAC currently will only play on iPods and iTunes. > > One thing to keep in mind is that both MP3 and AAC are considered > lossy formats, meaning data is lost in translation. It's not likely > you will hear the difference unless you have a very well trained ear, > but it's good to keep in mind. Let's say you have a song on a music CD > you want to add to your iTunes library. You import the song as an AAC > file. You probably would have a hard time telling which is the > original CD and which is AAC, even if you played them both side by > side. But if you were to burn the AAC back to an audio CD, the data > that was originally lost in translation to AAC is still gone. It's not > going to miraculously reappear just because you're converting it back > to its original format. Then if you play the two CDs side by side, you > might be more likely to hear the difference, even though the > difference would be very small. > > Data loss can be reduced by using a higher bitrate (128Kbps is > standard) and a higher frequency (44.1Khz is standard). By default, > when I import a CD, I use the AAC codec, since I only use iTunes and > my iPod, and I use a bitrate of 160Kbps with a frequency of 48Khz. > This increases the size of the files by maybe 33%, but they sound much > better than using the standard settings. So instead of a file being > 3.5MB, it might be 5MB. Not a huge difference with today's hard > drives. If I used a 3rd party MP3 player, I would probably use MP3 at > 192Kbps and 48Khz. Again, files would be about 50% larger than if I > had used the default settings. > > Hope this helps! > > Bryan C. Forrest > Macintosh Specialist > LifeNet > http://www.lifenet.org > > -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: text/enriched Size: 4458 bytes Desc: not available Url : http://www.math.louisville.edu/pipermail/macgroup/attachments/20050124/c249be02/attachment.bin
