[fritsch]

But, here is the deal:

Use the above sample I linked and deinterlace it via ffmpeg command line, once with weston and one time with yadif and compare :-) Use some libx264 encoding with a crf of 18 so that you don't introduce other artifacts and compare those.

Like: ffmpeg -i deinterlacing-test.mp4 -c:v libx264 -crf 19 -preset slow -vf "yadif=1:-1:1" -acodec copy "deinterlacing-test-yadif.mp4"
vs: ffmpeg -i deinterlacing-test.mp4 -c:v libx264 -crf 19 -preset slow -vf "w3fdif=complex:interlaced" -acodec copy "deinterlacing-test-weston.mp4"

You need ffmpeg 2.x of course.