Specifies JPEG decimation types.
| IG_JPG_DCM_1x1_1x1_1x1 | Decimation value 1x1_1x1_1x1. |
| IG_JPG_DCM_2x1_1x1_1x1 | Decimation value 2x1_1x1_1x1. |
| IG_JPG_DCM_1x2_1x1_1x1 | Decimation value 1x2_1x1_1x1. |
| IG_JPG_DCM_2x2_1x1_1x1 | Decimation value 2x2_1x1_1x1. |
| IG_JPG_DCM_2x2_2x1_2x1 | Decimation value 2x2_2x1_2x1. |
| IG_JPG_DCM_4x2_1x1_1x1 | Decimation value 4x2_1x1_1x1. |
| IG_JPG_DCM_2x4_1x1_1x1 | Decimation value 2x4_1x1_1x1. |
| IG_JPG_DCM_4x1_1x1_1x1 | Decimation value 4x1_1x1_1x1. |
| IG_JPG_DCM_1x4_1x1_1x1 | Decimation value 1x4_1x1_1x1. |
| IG_JPG_DCM_4x1_2x1_2x1 | Decimation value 4x1_2x1_2x1. |
| IG_JPG_DCM_1x4_1x2_1x2 | Decimation value 1x4_1x2_1x2. |
| IG_JPG_DCM_4x4_2x2_2x2 | Decimation value 4x4_2x2_2x2. |
The format of these ImageGear decimation constants is: IG_JPG_DCM_<H1>x<V1>_<H2>x<V2>_<H3>x<V3>, where Hi, Vi = horizontal and vertical decimation values for the i-channel. For a more detailed definition, see the JPEG Specification.