Hi,I wont to rotate QuickTime Move 180 degrees.
Now my file's matrix(tkhd) is
1 0 0
0 1 0
0 0 1
I got this matrix form Dumpster.
What is the 3 × 3 matrix for a rotation of 180 degrees?
A:
Multiplying by the following matrix will rotate a vector by 180 degrees in R3:
-1 0 0
0 -1 0
0 0 -1
Cirdec
2010-08-11 04:38:07
No. That has determinant -1. All rotation matrices have determinant 1.
Adam Rosenfield
2010-08-11 04:39:02
Apparently it's too late for me to answer, though my answer does exactly what it says it does. I have more bad answers, the next was a tensor or two linear transformations that combined rotate the entries in a matrix. Amusingly it didn't even occur to me to suggest a member of the rotation group. It would have helped to understand what a "Move" was.
Cirdec
2010-08-11 05:00:13
+5
A:
Assuming you want a 3x3 homogeneous matrix for a 2D rotation about the Z-axis, then the matrix you want is:
-1 0 0 0 -1 0 0 0 1
If you want to rotate about a different axis, then the matrix will be different.
Adam Rosenfield
2010-08-11 04:38:32