halfpack[=f]
Convert planar YUV 4:2:0 to half-height packed 4:2:2, downsam-
pling luma but keeping all chroma samples. Useful for output to
low-resolution display devices when hardware downscaling is poor
quality or is not available. Can also be used as a primitive
luma-only deinterlacer with very low CPU usage.
<f>
By default, halfpack averages pairs of lines when down-
sampling. Any value different from 0 or 1 gives the de-
fault (averaging) behavior.
0: Only use even lines when downsampling.
1: Only use odd lines when downsampling.
