.CDA vs. WAV files

What does it mean if a disc doesn't scan and get read as .cda files for a music cd?
Being .cda files, what does that mean exactly?
Any simple explanation?

I was once told all music cd's are .wav files, but then why do they read (sometimes as .cda?) sometimes .wav?

 

CDA is Microsoft's own file extension for its presentation of digital playback of CD audio. It only applies if you are looking at the CD drive in Windows Explorer, and they function kind of like a "shortcut" to open a media player.

Your question would be more answerable if you described what you are doing or where you see these files.

 

Audio CDs have 16 bit PCM digital audio at a sampling rate of 44.1khz

 

@harby is correct.

Also, WAV, AIFF, and "CD files" are all the same: uncompressed, 16-bit, 44.1kHz PCM data.

The difference is the file container. Someone will no doubt correct me on this technically, but basically audio CDs don't really have a "file system" the way a computer operating system does. Because CDs were never designed to be ripped, and were designed to be played at 1x speed in real time - and because of the need to protect the music from scratches as much as possible - CD audio tracks are sort of scattered around the disc radius. They're not quite organized neatly, in a consistently addressable way, as computer files are.

 

Yeah, kinda confused is why, so most CD's I have say the format .wav on my cd player.
Virtual DJ will say .cda instead.

Another thing I can't figure out, the POIs editor diagram for different file formats show different cue points, breaks, mixes, whatever else in the exact same compressed song of the original disc, is that normal?

 

The features you mention are not available on an audio CD - Original redbook CD doesn't even contain a digital version of the artist name. All of these are either looked up on the internet, matching the CD to a database of other CDs, by scanning the audio of the song to find out what previously known song it may match in a database (such as Musicbrainz Picard), or by scanning the audio file to guess from the sound what BPM or other audio characteristics it might have.

Errors or differing internet information can be obtained if the CD or audio file contents is guessed wrong.

All these functions are specific to the software you are using, are not part of the plain audio that is on a CD, and would be better focused on forums for the particular software package if need further understanding of how the software works.

 

Then how does my cd player show artist name and track names, bpm, file format, album name and is not hooked to the internet?

 

The reason why I state "original redbook" above is because there was an extension added to CD late-90's called CD-TEXT, to include text data on the disc. Only both new players and new discs used together have a chance of supporting this, and it is not universally used still.

BPM is not part of CD-TEXT info, but DJ CD players may scan the audio on the disc to listen and "count" the beats to assist the mixologist.

 

Was the CD- TEXT not able to be done until the late 90's on the "original redbook" discs, or because it wasn't allowed?

Also, if the programs on the computer don't get information from the disc itself, then how does it know the information at all in like 10 seconds, there's millions of albums?

 

The CD is looked up in an internet database by the length of songs, pregap information etc. that is usually unique freedb.org > FAQ - the audio doesn't have to be analyzed.

You can click on the CD-TEXT link in my post above to read more about how that works. It just wasn't thought up at the time (1982) of CD release. It was amazing technology for a consumer player just to play digital audio.

 

From what I understand, a difference between CDA (used to store data on CDs) is that the data isn't encoded directly (reading zeroes and ones). Instead, it is encoded in the data flips of consecutive bits as follows:

• 0 to 0 = 0
• 1 to 1 = 0
• 0 to 1 = 1
• 1 to 0 = 1

 

So, what I am wanting to know basically is: 1. Can a disc be read by by a computer program to know which disc it is, if it ain't CDA format?
2. Do only "original redbood" discs use CDA format?
3. CDA will only show up on a true real copy of the music?

 

I have no answer for the first and third question, and can only guess at the second question. I'd think that any CD-R and CD-RW burned as a regular CD would use the CDA format. However, there is a difference between regular CDs and recordable CDs when it comes to how they have to be read by the CD player's laser. I had a regular CD player that wasn't able to play recordable CDs and I think is was because recordable CDs aren't as reflective as regular CDs. If I'm wrong please correct me.

 

My current cd player won't play CD-RW but will play regular CDR's. Why? No idea.

If you burn a CDR or CD-RW disc of an album, programs will read it as an unknown album and CDR format, as far as I've ever seen.

 

Correct. It's the Solomon-Reed error correction. But, it has nothing to do with .cda, which is nothing more than what @harby stated.

Some will, some won't. The reason is most likely due to the way in which the information is burned onto a CD-RW. The CD player may not be able to read it. Also, if you do not finalize the CD-R or CD-RW, you cannot play it on any CD player. Closing it writes a table of contents for the CD player to read to know what's on the CD, and how to deal with it. All playable CDs have a table of contents.

 

Compact Discs use an audio format that computers don't recognize, which is you see the .cda "markers". A ripping program coverts the audio for playback on a PC.

 

Makes sense now, but if the computer programs are readings 0 1010011's as you said, doesn't the 0011000's techniqually make it reading the info from the disc? Also, I would guess that the 0001100's can't be duplicated to another disc? Making the disc with 0011011's authentic because only the audio is transferred?

 

I don't know if you have me on ignore, but it is as harby stated before: .cda is only a representation of the audio interpreted by Windows. It isn't a format.