When to crop within order of operations

[franciscola]

Is there a best practice for whether a video should be cropped before or after de-interlacing within a filter chain? Likewise with IVTC, assuming that field matching and decimation are separate steps, should you crop before field matching, after field matching but before decimation, or after decimation? Thanks!

[manono]

If cropping before deinterlacing or IVTC you have to be very careful how you crop or you ruin the video. So, it's safer to deinterlace or IVTC first. That's how I do it anyway.

[hello_hello]

If there's large black bars I often crop them before de-interlacing or applying IVTC. As long as you make sure you crop in multiples of 4 (for YV12) it should be okay. You can always crop a tad less than you'd prefer to make sure the cropping is mod4, then crop a few more pixels after deinterlacing if need be.

Resizing should always be done after de-interlacing though.