Boing! lua

function initLag()

    for i=1,movie.length() do
        j = movie.getinput(i-1, 1)
        if (j["Left"] or j["Right"]) then
            tastudio.setlag(i, false)
            for lags=1,12 do
                tastudio.setlag(i+lags, true)
            end
        elseif (j["Up"] or j["Down"]) then
            tastudio.setlag(i, false)
            for lags=1,13 do
                tastudio.setlag(i+lags, true)
            end
        end
    end

end

--this function should mark all the appropriate lag frames without having to play through the run. not fully tested
--initLag()

while true do
    isLagged = false
    if (not tastudio.islag(emu.framecount()-14)) then
        j = movie.getinput(emu.framecount()-14, 1)
        if (j["Up"] or j["Down"]) then
            tastudio.setlag(emu.framecount(), true)
            isLagged = true
        end
    end
    if (not isLagged) then
        for i=emu.framecount()-13,emu.framecount()-2 do
            j = movie.getinput(i, 1)
            if (not tastudio.islag(i)) then
                if (j["Left"] or j["Right"] or j["Up"] or j["Down"]) then
                    tastudio.setlag(emu.framecount(), true)
                    isLagged = true
                end
            end
        end
    end

    --this could print in the console when it finds a wait frame, but it's easier to just look
    --[[j = movie.getinput(emu.framecount()-1,1)
    if (not isLagged and not (j["Left"] or j["Right"] or j["Up"] or j["Down"])) then
        print(j)
    end]]

    emu.frameadvance()
end