| Value | Description |
|---|---|
| ioJPEG_RGB | Separate RGB channels |
| ioJPEG_GRAYLEV | Unique intensity channel (gray levels) |
| ioJPEG_YCbCr | Three channels (CCIR Recommendation 601-1) |
| ioJPEG_CMYK | Four channels (Cyan Magenta Yellow Black) - linear conversion |
| ioJPEG_YCbCrK | Four channels (YCbCr and Black) |