Comprssing 1 hour 54 min mp3 audio to fit cd

Im using XP Media Center 2006 with all the updates; I’m using Audacity 2.0.2 downloaded directly from Internet; I’m trying to compress a 1 hour 54 minute mp3 audio file so that I can burn it to a standard Sony CD. Here are the steps I’m using:

File > Open (and import audio) > File > Export > Options (for Specify MP3 options I’m using Constant; for Quality I’ve used everything from 128 to 32, and for Channel Mode I’ve used Joint Stereo). No matter what Quality I choose (from 128 to 32), Sonic MyDVD is showing that I am always 34 minutes 31 seconds over the CD limit.

Is Audacity not compressing the file? Or do I need to do something different?

Thank you.

A “standard” audio CD will hold up to 79.8 minutes of audio. That’s it - that’s the red book specification.

Audio CDs use uncompressed audio data, so no matter how much you compress the audio (and how bad you make it sound :wink:), when you create an “audio CD” the data will be “expanded” (uncompressed) back to its full size.

Some CD players (but not all) support “data CDs” which contain MP3 files. These are not standard audio CDs. They will play on computers and on some CD players.
To create this type of CD, select “data CD” in your CD burning software.

If you require a standard audio CD (compatible with most CD players) there is no alternative than to split the recording across 2 or more disks.

For making a standard audio CD you should export from Audacity in WAV format and set the “Project Rate” (bottom left corner of the main Audacity window) to 44100. This is the standard format for audio CDs.

If you want the CD to have multiple tracks so that you can skip from one track to the next (rather than just one long track) then you will need to split the recording into multiple files. Use your CD burning software to arrange the tracks into the order that you want.

See here for a tutorial with more information:

You need to do something different. Music CDs, real ones, work by time, not filesize. You have to do whatever is necessary to make the show 78 minutes long. Full Stop.

Many cars and music players accept MP3 files. My sister’s car will do that. My older truck will not.



Just for future reference -

Since bitrate is kilo_bits_ per second, we can change bits to bytes, seconds to minutes, etc., and with some rounding we can estimate file size as follows:
File Size in MB = Bitrate in kbps x Playing time/140

A regular audio CD has a bitrate of 1411kbps, which makes it around 5 times the size of a good quality MP3.

Yes, the bitrate of an uncompressed music file (which nobody ever calculates) is startlingly higher than any compressed work. Koz