ttml/ebu-ttd import: fix first sample duration when ts_begin is not zero as the container imposes #192
ttml/ebu-ttd import: fix first sample duration when ts_begin is not zero as the container imposes
#192

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