Many 3D films viewers experience visual discomfort and head ache. The reason of this discomfort is in stereoscopic errors such as excessive horizontal and vertical disparity, color and sharpness mismatch in the left and right views. Thus, the production studios have to make a high quality conversion. The stereoscopic problems have been investigated thoroughly by Graphics & Media Lab. The report is available to all industry professionals here:
http://compression.ru/video/vqmt3d/second-report/