fix non consistent offset for download cc @jeanlf please check
fix non consistent offset for download
cc @jeanlf please check

Bevara/Access-open,aymanelyaagoubi/gpac,rbouqueau/gpac_brew_travis,RodolpheFouquet/gpac,Bevara/Access-open,gpac/gpac,rauf/gpac,RodolpheFouquet/gpac,porcelijn/gpac,ARSekkat/gpac,ARSekkat/gpac,RodolpheFouquet/gpac,RodolpheFouquet/gpac,porcelijn/gpac,drakeguan/gpac,aymanelyaagoubi/gpac,epam/gpac,vladimir-kazakov/gpac,ARSekkat/gpac,Bevara/Access-open,porcelijn/gpac,aymanelyaagoubi/gpac,nguyen-viet-thanh-trung/gpac,rbouqueau/gpac_brew_travis,DmitrySigaev/gpac,epam/gpac,gpac/gpac,Bevara/Access-open,ARSekkat/gpac,psteinb/gpac,DmitrySigaev/gpac,psteinb/gpac,RodolpheFouquet/gpac,gpac/gpac,aymanelyaagoubi/gpac,aymanelyaagoubi/gpac,drakeguan/gpac,emmanouil/gpac,gpac/gpac,drakeguan/gpac,nguyen-viet-thanh-trung/gpac,porcelijn/gpac,rbouqueau/gpac_brew_travis,porcelijn/gpac,epam/gpac,DmitrySigaev/gpac,rauf/gpac,drakeguan/gpac,rbouqueau/gpac_brew_travis,DmitrySigaev/gpac,Bevara/Access-open,rbouqueau/gpac,gpac/gpac,DmitrySigaev/gpac,vladimir-kazakov/gpac,nguyen-viet-thanh-trung/gpac,psteinb/gpac,rauf/gpac,rbouqueau/gpac,gpac/gpac,RodolpheFouquet/gpac,psteinb/gpac,drakeguan/gpac,gpac/gpac,epam/gpac,nguyen-viet-thanh-trung/gpac,porcelijn/gpac,nguyen-viet-thanh-trung/gpac,epam/gpac,DmitrySigaev/gpac,rbouqueau/gpac,nguyen-viet-thanh-trung/gpac,vladimir-kazakov/gpac,rbouqueau/gpac_brew_travis,gpac/gpac,rbouqueau/gpac,rauf/gpac,vladimir-kazakov/gpac,emmanouil/gpac,rbouqueau/gpac,emmanouil/gpac,emmanouil/gpac,ARSekkat/gpac,aymanelyaagoubi/gpac,rbouqueau/gpac_brew_travis,psteinb/gpac,rbouqueau/gpac,epam/gpac,rbouqueau/gpac,vladimir-kazakov/gpac,vladimir-kazakov/gpac,rauf/gpac,ARSekkat/gpac,psteinb/gpac,rbouqueau/gpac,drakeguan/gpac,Bevara/Access-open,emmanouil/gpac,emmanouil/gpac,rauf/gpac