.cda file
.cda is a common filename extension denoting a small (44 byte) stub file generated by Microsoft Windows for each audio track on a standard "Red Book" CD-DA format audio CD. These files are displayed in the directory for the CD in the format Track##.cda, where ## is the track number.[1][2][3]
.cda files do not contain actual PCM sound data. Instead, they point to where on the disc each track begins and ends. If copied to a computer, the files cannot be used independently because they contain only index information. To extract audio, ripping software must be used to convert the CD-DA stream into formats such as WAV or MP3.[4][5]
Organization of a CDA file
Every .cda file is exactly 44 bytes and follows a RIFF structure with a single "CDDA" chunk.[6][7] Multi-byte values are encoded in Intel little-endian order, and timing values are measured in frames (75 per second), consistent with the Red Book standard.[8]
| Offset | Size | Field | Description |
|---|---|---|---|
| 0x00 | 4 | "RIFF" | RIFF header |
| 0x04 | 4 | 0x24 (36) | Chunk size, little-endian |
| 0x08 | 4 | "CDDA" | Chunk identifier |
| 0x0C | 4 | "fmt " | Subchunk header |
| 0x10 | 4 | 24 | Subchunk size |
| 0x14 | 2 | Version | Typically 1 |
| 0x16 | 2 | Track number | Starting at 1 |
| 0x18 | 4 | Identifier | For use with cdplayer.exe |
| 0x1C | 4 | Start offset | Track start, in frames |
| 0x20 | 4 | Track duration | Total frames |
| 0x24–0x26 | 3 | Start time | Frames, seconds, minutes |
| 0x27 | 1 | 0x00 | Reserved/null |
| 0x28–0x2A | 3 | Duration | Frames, seconds, minutes |
| 0x2B | 1 | 0x00 | Reserved/null |
The 4-byte identifier at offset 0x18 was used by Windows 95 and Windows 98 CD Player (cdplayer.exe) to link to the cdplayer.ini file, where users could manually enter album and track data. This identifier is unrelated to the Disc ID values later used by CDDB or FreeDB.[9]
Software support
.cda files are recognized by Windows Media Player in all modern versions of Windows. Selecting or double-clicking a .cda entry plays the corresponding track from the audio CD, not the stub file itself. Windows Media Player also allows tracks to be "ripped" into other formats such as MP3 or WAV.[5][10]
Other common media players also support CDs that appear as .cda entries:
- Winamp includes a CDDA input plugin (IN_CDDA.dll) to interpret CD tracks, though it does not play the 44-byte stub itself and has been subject to vulnerabilities involving malformed .cda references.[11][12]
- iTunes for Windows detects audio CDs and displays tracks as .cda files, but cannot play .cda stubs copied to disk. Playback and importing require the original disc.[13][14]
- VLC media player recognizes .cda files on inserted audio CDs and can convert tracks into other formats, but like other players it cannot use .cda stubs once removed from the disc.[15]
Legacy programs such as cdplayer.exe (Windows 95/98) and early versions of MusicMatch Jukebox also relied on .cda files to access CD audio, using identifiers in cdplayer.ini for album and track information.[9][16]
Decline of use
Although Windows 10 and Windows 11 continue to support .cda files for native CD playback, their relevance has declined significantly with the move to file-based and streaming music. Modern media software and operating systems increasingly omit optical drive support, making .cda primarily a legacy feature.[17][2]
See also
References
- ^ "CDA File Extension". Filext.com. Retrieved 8 September 2025.
- ^ a b "CDA File Extension – What is a .cda file?". ReviverSoft. Retrieved 8 September 2025.
- ^ Kessler, Gary. "File Signatures Table". GaryKessler.net. Retrieved 8 September 2025.
- ^ "Tutorial – How to import CDs". Audacity Manual. Retrieved 8 September 2025.
- ^ a b "File types supported by Windows Media Player". Microsoft Support. Retrieved 8 September 2025.
- ^ "getID3 RIFF.CDDA dissection". getID3.org. Retrieved 8 September 2025.
- ^ "CDA File Format". FileFormat.com. Retrieved 8 September 2025.
- ^ "What is the Red Book CD format?". Travsonic. Retrieved 8 September 2025.
- ^ a b "CD Player Q&A". Hinzen.de. Retrieved 8 September 2025.
- ^ "How to Play CDA Files". HitPaw. Retrieved 8 September 2025.
- ^ "Vulnerability in Winamp CDA input plugin". Check Point. 2009. Retrieved 8 September 2025.
- ^ "Winamp Help – CD playback". Winamp Heritage. Retrieved 8 September 2025.
- ^ "Why can't iTunes play CDA files?". Apple Support Communities. Retrieved 8 September 2025.
- ^ "Convert music file formats in iTunes on PC". Apple Support. Retrieved 8 September 2025.
- ^ "CDA File – Description and uses". MiniTool. Retrieved 8 September 2025.
- ^ "The CDA File Format Explained". Nick Landis Audio Blog. 2019. Retrieved 8 September 2025.
- ^ "Windows 11 and CDA file playback issues". WindowsForum. Retrieved 8 September 2025.
External links
- Archived CDA file format specification (Moon-soft.com, 2006)