ARCore : decompose view matrix - matrix

Question

I'm trying to get eye coordinates (camera's position, direction and up) from pose's view matrix, but what I get is not what I expected.
First, my goal is an Yup coordinate system :
I'm not sure ARCore use the same system, I did not found precise informations about the used coordinate system.
Next, I'm decomposing the view matrix, but if the results are mathematically good (direction and up seems to be in the good directions, position seems to have the good scale) the result is very cahotic since my camera move strangely around my scene.
// Get camera matrix and draw.
float[] viewmtx = new float[16];
frame.getViewMatrix(viewmtx, 0);
Vector3 pos = new Vector3(viewmtx[12], viewmtx[13], viewmtx[14]);
Vector3 camDir = new Vector3(viewmtx[8], viewmtx[9], viewmtx[10]).nor().scl(-1);
Vector3 camUp = new Vector3(viewmtx[4], viewmtx[5], viewmtx[6]).nor();
Does something sound strange for you?

Answer 1

Here is the answer :
The device / configuration i'm using is in landscape mode, so the coordinate frame is not this one.
Here is my fix :
Vector3 pos = new Vector3(viewmtx[12], viewmtx[13], viewmtx[14]).scl(1000);
Vector3 camDir = new Vector3(viewmtx[8], viewmtx[9], viewmtx[10]).nor();
Vector3 camUp = new Vector3(viewmtx[4], viewmtx[5], viewmtx[6]).nor();
if (isLandscape) {
pos = new Vector3(viewmtx[12], viewmtx[13], viewmtx[14]).scl(1000);
camDir = new Vector3(-viewmtx[8], -viewmtx[9], -viewmtx[10]).nor();
camUp = new Vector3(viewmtx[0], viewmtx[1], viewmtx[2]).nor();
}