While there are three different types of data can be written to CD, there is only one type of data that can be written to DVD.

All CD data types share the same physical block size of 2352 bytes. Each data type have different user block sizes, the bytes effectively available to the user. The sizes depend on the level of error correction adopted: the lower the read accuracy required, the smaller the error correction code required, the larger the user data block is.

The following is an overview of CD compatible data formats.

• Audio:
  
  No extra error correction is required to read and play back audio. The user blocks size matches the physical block size of 2352 bytes.
   

• Mode 1/Mode 2 Form 1:
  
  Mode 1 and Mode 2 Form 1 formats are used to store digital data and require the highest read accuracy. The user block size is 2048 bytes (2 kilobytes). The remaining bytes are used to store synchronization patterns, block headers, Error Correction Codes (ECC), and Error Detection Codes (EDC).
   

• Mode 2 Form 2:
  
  This format is used almost exclusively to store digital video data, thus requiring only moderate read accuracy. The user blocks size is 2324 bytes. The remaining bytes are used to store synchronization patterns, block headers, and Error Detection Codes (EDC).