Four-Character Codes (FOURCC)

DirectDraw utilizes a special set of codes that are four characters in length. These codes, called four-character codes or FOURCCs, are stored in file headers of files that contain multimedia data, such as bitmap images, sound, or video. FOURCCs describe the software technology that was used to produce multimedia data. By implication, they also describe the format of the data itself.

DirectDraw applications use FOURCCs for image color and format conversion. If an application calls the IDirectDrawSurface7::GetPixelFormat method to request the pixel format of a surface whose format is not RGB, the dwFourCC member of the DDPIXELFORMAT structure identifies the FOURCC when the method returns.

In addition, the biCompression member of the BITMAPINFOHEADER structure can be set to a FOURCC to indicate the codec used to compress or decompress an image.

FOURCCs are registered with Microsoft by the vendors of the respective multimedia software technologies. Some common FOURCCs appear in the following list.