Similar to YV12, this format comprises an NxN Y plane followed by "rectangularly adjacent" (N/2)x(N/2) U and V planes. Lines of U and V pixels are interleaved at half stride boundaries below the Y plane.
| Horizontal | Vertical | |
| Y Sample Period | 1 | 1 |
| V (Cr) Sample Period | 2 | 2 |
| U (Cb) Sample Period | 2 | 2 |
Microsoft defines this format as follows:
"The same as IMC1, except that Cb and Cr lines are interleaved at half-stride boundaries. In other words, each full-stride line in the chrominance area starts with a line of Cr, followed by a line of Cb that starts at the next half-stride boundary. (This is a more address-space-efficient format than IMC1, cutting the chrominance address space in half, and thus cutting the total address space by 25%.) This runs a close second in preference relative to NV12, but NV12 appears to be more popular."
Based on: IMC1
Duplicate formats: IMC4