#!/usr/bin/perl -i.oldproj

while (<>)
{
    if (/^app\.video\.addFilter\(\"swissarmyknife\"/)
    {
        s/(?=init_start_frame)/lookahead_n_frames=0\",\"/
            if !/lookahead_n_frames/;
        s/(?:(?<=init_start_frame=)|(?<=init_end_frame=))(\d+)/$1-1/eg;
    }
    elsif (/^app\.video\.addFilter\(\"computeaverage\"/)
    {
        s/(?:(?<=start_frame=)|(?<=end_frame=))(\d+)/$1-1/eg;
    }

    print;
}