force pixel aspect ratio to 1.0 if zero denominator to avoid PAR of NaN
force pixel aspect ratio to 1.0 if zero denominator to avoid PAR of NaN

mcanthony/oiio,cwilling/oiio,lgritz/oiio,YangYangTL/oiio,bdeluca/oiio,scott-wilson/oiio,OpenImageIO/oiio,YangYangTL/oiio,scott-wilson/oiio,micler/oiio,sambler/oiio,mcanthony/oiio,OpenImageIO/oiio,mcanthony/oiio,lgritz/oiio,cwilling/oiio,lgritz/oiio,micler/oiio,bdeluca/oiio,OpenImageIO/oiio,cwilling/oiio,YangYangTL/oiio,OpenImageIO/oiio,bdeluca/oiio,lgritz/oiio,sambler/oiio,YangYangTL/oiio,cwilling/oiio,micler/oiio,micler/oiio,mcanthony/oiio,scott-wilson/oiio,scott-wilson/oiio,sambler/oiio,sambler/oiio,bdeluca/oiio