How to Convert an MP3 to CDA Format for Free
The CDA (short for "compact disc audio") file format is an audio format that is used to allow songs to be played on standard CD players. Any CD that you buy in a store like Best Buy or Borders will be filled with tracks encoded in the CDA file format. If you want to convert your MP3 tracks to the CDA format (which is done automatically during the CD-burning process), you can use a program that is already built into your operating system--Windows Media Player.
Launch Windows Media Player. To accomplish this, click "Start." Click on the "All Programs" button (or the "Programs" button if you're an XP user) and then click "Windows Media Player."
Click on the button at the top of Windows Media Player that is clearly labeled "Burn." This opens a new column in Windows Media Player.
Locate the MP3 files on your computer's hard drive that you'd like to convert to the CDA format and burn to a CD. It will be easier for future steps if you condense all of these files down to a single folder on your hard drive.
Drag any MP3 files you want to convert into the CDA format and burn to a CD into this new "Burn" column on the right side of Windows Media Player. Once converted to the CDA file format, a standard audio CD can hold 80 minutes of music. Pay close attention to the "Total Running Time" indicator at the bottom of this bar in Windows Media Player to ensure you aren't trying to fit too much music on your CD.
Click the "Start Burn" button.
Insert a blank CD into your CD burner (when prompted by Windows Media Player). Windows Media Player will now analyze each of the MP3 files you have selected and convert them to the compact disc audio file format. These newly converted files will then be burned to the CD in your CD burner.