Cropping's effects on interlacing - also, to deinterlace or no...

[brassplyer]

Starting with DV video, I need to crop it to get rid of switching noise on the bottom and the blank areas on the sides for playback on an HDTV.

However, if I crop the switching noise off the bottom, this slightly expands the image and the interlace lines, and it seems removes some. Does the area with the switching noise count toward the number of interlace lines? Does this matter? Does the TV and or player expect the interlace lines to be a particular relative size and place or does it just look at fields without regard to this?

Should the video be deinterlaced first, cropped and reinterlaced or would it be better to deinterlace it with QTGMC to 59.94 progressive and upscale to 720p?

Thanks for all input.

[jagabo]

If you're going to upscale you'll need to deinterlace. And at 720p there's no point in re-interlacing the video since 720i doesn't conform to any standard. Since you're going to deinterlace and upscale it doesn't matter how much of the frame you crop away -- except for colorspace limitations -- interlaced YV12 must have a mod 4 frame height.