: Audio File Formats...


The Doug
Jan 29th, 2004, 09:17 AM
My naive question for today: what is the difference between AAC, AIFF, and MP3 files in terms of cross-platform compatability and sound quality? I've got some GarageBand tracks that I want to burn to CDs and share with friends, not all of whom are Mac or iTunes users. I don't want to send them files they won't be able to open, or will have crummy sound quality.

While I'm at it - last evening I selected some of my tracks in iTunes, and converted them from AIFF to MP3, then I burned them to a disc. This morning when I opened the disc on my WinXP box at work, the files didn't appear as MP3-format, but with a .cda extension. Huh?

(( p g ))
Jan 29th, 2004, 10:04 AM
Hardly a naive question: all these formats can get confusing! In essence, AIFF is an uncompressed audio format that audio CDs use. They are compatible on Mac and Win machines, but because of their bloated file sizes (30-50 megs per track), most prefer to convert them to MP3 format. Again, this format is cross-platform compatible.

Last, there is the AAC (which in essence is the newer MP4 format). As I understand it, this format is cross-compatible provided that the Windows machines are using iTunes (this is because the format is governed my Quicktime, which is installed as part of iTunes).

If you can't be sure that everyone has iTunes, your best bet for a hassle-free format is MP3, encoded at a 160 or 192 bit rate.

Now as to your question about your CD, it sounds like you might have inadvertently burned the AIFF files to disc, which would explain the presence of the .cda file extension. Put the problem disc in your Mac. If it loads and plays like an audio CD, this will confirm my guess. If it loads as a data CD (the Finder will show each track as an MP3 or AAC), then the problem lies elsewhere.

Did you burn this CD with iTunes or Toast?

Chealion
Jan 29th, 2004, 12:26 PM
AAC = Advanced Audio Codec. Part of MPEG4 (Think of it as the next version of Mp3 if you will)
MP3 = MPEG 1 Layer 3. Standard for compressing audio.
AIFF/WAV = Uncompressed audio. An 80 minute CD-R will hold 80 minutes of AIFFs or WAVs.

CDA = CD Audio aka Tracks on a CD, they play in any CD player.

By burning them on a CD, it will play anywhere.

Mp3s will require a Mp3 player, and so any computer newer then 8 years old should be able to play Mp3s. All that is needed is Winamp, Windows Media Player or Quicktime.

AACs require QuickTime 6.4 or iTunes.

When you burn a CD as an audio CD, any files you have are converted to .cda which is the way the computer represents the tracks on an audio CD. If you wanted to burn the Mp3s themselves, you should have burned an Mp3 CD or a Data CD instead.

gordguide
Jan 30th, 2004, 07:51 AM
ACC is a cross-platform standard, which explains why Microsoft refuses to support it. It is a newer and more sophisticated format that was created to replace mp3.

AIFF (Audio Interchange File Format) is also x-platform, which also explains why Microsoft refuses to use it; they substituted the nearly identical but incompatible WAV format.

CDs use AIFF files but they are slightly modified (in a wrapper) to create the file format used in Redbook Standard disks (ie CD).

Bolor
Jan 30th, 2004, 09:19 AM
If you burn MP3 as a data cd, you should choose the ISO 9660 format so that Winbloze machines can read it. Otherwise, toast can burn a music CD in the MP3 format that can be read by most machines ... incuding MP3 compatible DVD/CD players