What is a CDA file?
A file with .cda extension is a small stub file generated by Microsoft Windows for each audio track on a an audio CD. These files contain a typical information such as track times and a Windows shortcut that enables users to access the specific audio tracks. The CDA files are not music, but they are pointing to a music file existing somewhere on the storage. We can say it as a shortcut of an audio file which is located on a CD.
CDA File Format
The CDA file format is used to tell a computer that which audio file to play on a CD. So, the CDA files become useless separated from a CD they represent. The CDA files are commonly considered as RIFF resources. There is only one chunk which is named “CDDA” and contain only one data block called “FMT " in current version of .cda file. This block is 24 bytes long. The identifier created by Windows is used by the Windows 95 and Windows 98 related CD drive and its player can’t connect to FreeDB or CDDB. So that it can display song title and the artist name, which you have to manually enter this information in the cdplayer.ini file.
Organization of a CDA file
The following table shows the information about typical offsets:
| offset | length | content |
|---|---|---|
| 0x00 | 4 | the 4 ASCII characters “RIFF” |
| 0x04 | 4 | the size of the following chunk: always 36 (44 - 8), on 4 bytes (Intel order) |
| 0x08 | 4 | chunk identifier: the 4 ASCII characters “CDDA” |
| 0x0C | 4 | the 3 ASCII characters “fmt” followed by a space |
| 0x10 | 4 | length of the chunk: always 24, on 4 bytes (Intel order) |
| 0x14 | 2 | version of the CD format, on 2 bytes (Intel order). In May 2006, always equal to 1. |
| 0x016 | 2 | number of the range, on 2 bytes (Intel order). The first track has the number 1. |
| 0x18 | 4 | identifier calculated by Windows for cdplayer.exe. |
| 0x1c | 4 | range offset, in number of frames (Intel order) |
| 0x20 | 4 | duration of the track, total number of frames (Intel order) |
| 0x24 | 1 | range position: frames |
| 0x25 | 1 | range position: seconds |
| 0x26 | 1 | range position: minutes |
| 0x27 | 1 | a null byte (binary value 0) |
| 0x28 | 1 | duration of the track: frames |
| 0x29 | 1 | duration of the track: seconds |
| 0x2a | 1 | duration of the track: minutes |
| 0x2b | 1 | a null byte (binary value 0) |
