Raw video confiscated from the journalists shows the photographer Johan Persson holding an automatic weapon. In the edited short version of the film, which was shown at court, a gun shot is heard in the background.
The sound was not part of the original version which the prosecutor admitted.
The two freelance journalists, Persson and his reporter Martin Schibbye, travelled illegally into Ethiopia's restive eastern Ogaden region in the summer.
They have pleaded guilty to entering the country without a visa but deny the terror charges.