ffmpeg -i input.mp4 -vf "drawbox=w=iw:h=2:y=ih/2:color=black:t=fill, eq=brightness=0.05:contrast=1.2" -c:a aac -b:a 64k y2k_scanlines.mp4
To simulate a bad DV tape connection, use the geq (general equation) filter for random digital blocks, or simply stack the noise filter heavily. y2k ffmpeg
noise=c0s=20:c0f=t
eq=brightness=0.1:contrast=1.4:saturation=1.2 ffmpeg -i input