file extensions

I’m confused on what happens to audio file extensions when burning and editing. I downloaded MP3 files and burned them to a CD. When I try to open one up from the new CD, (to edit in Audacity), I get the message: “…Track01.cda is an audio CD file. Audacity does not open this type of file. Try ripping it to a native audio format that Audacity can import.” I don’t understand why a “.CDA” file won’t open, nor do I understand what a Native Audio format is. I’ve tried converting the MP3 to .WAV and still this message, after the .WAV file is burned to a CD. When I was able to edit one file (I still don’t know why I was able to get Audacity to accept it) the file then was given a DATA extension, for example “Track3-Data” I hope someone can explain this to me. If you can, please send a duplicate of your answer, should I not check this site every day.

There are two main types of CD that you can make - “data” CDs and “audio” CDs.

Data CDs contain files, just like the files on your hard drive. The files can be read on a computer, but most CD players will not play data CDs. The data on a data CD can be any kind of file - it could be a word processor document or picture or a program… so it’s not surprising that it won’t play on a CD player.

Audio CDs are very similar to bought CDs that you would play on your CD player. They do not contain “files”, they just contain a stream of data (the audio data) and some track pointers (that tell the CD player where the tracks start and finish). These “pointers” are the CDA files.

CDA files are not audio - they just point to the (invisible) audio data on the CD so that your CD player knows where to find track 1, 2, 3, 4, 5…

Audacity imports audio data from files - it can’t read the data directly from an audio CD. To use audio data from a CD you need to “Rip” the audio data from the disk. “Ripping” is digitally extracting the audio data and writing it to files. There are special programs (CD rippers) that do this. One good free CD ripper is “C-Dex”.

When you make (burn) an audio CD on your computer, you use a program (CD burning program, such as Nero, In CD, CDBurnerXP,…) to read files from your computer and turn them into a CD. Good CD burning programs will give you the option to create a data CD (contains computer files) or an audio CD (contains a stream of audio data and CDA pointers and can be played on a CD player). Some of these programs can create audio CDs from several types of file. CD burners will always accept 44100Hz/16bit WAV files as this is virtually the same format as the audio data on the CD. Some CD burning programs can convert other file types (such as MP3 files) into audio CD data and produce ordinary audio CDs from them.

I don’t think that was the file extension, I think that was just the file name. It sounds like you may have rippe a CD track without realising that you’d done it. When you rip a CD the file names are often something like “Track3-Data.wav” Windows is a pain here in that by default it hides the last part of a file name (the file extension).

cda is not really a file
just looks like one

it is an index to the one long pcm file on the cd
so win knows where to start from to play a selection of music
that you think is a cda track

you need to rip the disk if you want separate wav files

They did that crazy Music CD format thing to save space. The equivalent pile of WAV files would be larger with all their file header and footer information. That’s why you need a Music CD Authoring program to create a CD and a Ripper to get the music back off.

The quality doesn’t change. It’s always 44100, 16-bit, Stereo which is why the maximum capacity is 79 min 30 seconds. +/- seconds either way.

Do you have Windows set to show you file extensions? I’m assuming you’re in Windows. That can go a long way to letting you see what you’re doing.

And next time please post in the forum appropriate to your machine and Audacity version instead of Generic Audio. Thanx.