window.addEventListener('keypress', function (evt) {
    if (video.paused) { //or you can force it to pause here
        if (evt.keyCode === 37) { //left arrow
            //one frame back
            video.currentTime = Math.max(0, video.currentTime - frameTime);
        } else if (evt.keyCode === 39) { //right arrow
            //one frame forward
            //Don't go past the end, otherwise you may get an error
            video.currentTime = Math.min(video.duration, video.currentTime + frameTime);
        }
    }
});