StereoRectify ROI Results

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Hi I could not get always valid roi from stereo rectify. Results that I got is below

Valid ROI
"0" "31" "1269" "912"
"0" "0" "0" "0"
Errors: Cam Left "0.234922" Cam Right "0.246169"
Reprojection Error Stereo: "0.274664" \n

How could i get always valid results from stereo rectify?