CD sector contents

• A standard 74 min CD contains 333,000 sectors.
• Each sector is 2352 bytes, and contains 2048 bytes of PC (MODE1) Data, 2336 bytes of PSX/VCD (MODE2) Data, or 2352 bytes of AUDIO.
• The difference between sector size and data content are the Headers info and the Error Correction Codes, that are big for Data (high precision required), small for VCD (standard for video) and none for audio.
• If extracting the disc in RAW format (standard for creating images) always extract 2352 bytes per sector, not 2048/2336/2352 bytes depending on data type (basically, extracting the whole sector). This fact has two main consequences:
  • Recording data CDs at very high speed (40x) can be done without losing information. However, if done the same with PlayStation or Audio CD it will result in an unreadable PlayStation disc or an audio CD with lots of clicks because there are no error correction codes and the errors are more likely to occur at high speed recording.
  • On a 74 minute CD can fit very large RAW images, up to 333,000 × 2352 = 783,216,000 bytes (747 MiB). This should be the upper limit for a RAW image created from a 74 min CD. If the stored standard data (backup files), it can burn only 333,000 × 2048 = 681,984,000 bytes (650 MiB).
• Please note that an image size is always a multiple of 2352 bytes (the size of a block) when extracting in RAW mode.