Using resize on interlaced source?

[Palmnut]

I'm using DVD2SVCD 1.2.2B3 as a short cut to crop and re-encode a MPEG2 capture from my (PAL) Hi8 video camera to get rid of overscan. I've read elsewhere that video should always be de-interlaced before applying a resize to ensure a good quality answer. Is this so? How should I do this?

[scharfis_brain]

Do NOT resize interlaced video!

it will destroy the image quality.

If you are bothered be the overscan, just black it out. but never ever resize interlaced video by small amounts

(HDTV -> SDTV is okay, cause it is a large amount to resize)

[r6d2]

Originally posted by scharfis_brain
Do NOT resize interlaced video!

it will destroy the image quality.@scharfis_brain, is this statement valid even for interlaced resizing ala FitCD? :confused:

[scharfis_brain]

even more, yes.

fitcd uses

separateifields.resize(halfheight).weave()

resizing, which completely destroys the spatial detail and introduces a wrong spatial alignment to the fields.

even die far better method:

thresholdedbobber() #tmcbob(), kernelbob() or whatever
resize()
separatefields()
selectevery(4,0,3)
weave()

, which cares for static areas (those ones get resized as progressive) and interlaced areas (those are benefiting from the advanced interpolation of the bobber)
is crappy, cause on low resizing ratios from >0% to about 15%, there WILL be a wavy structure in the video on high detailed areas, cause they are interpolated-interlaced.

[r6d2]

Interesting. I've never noticed that effect when using FitCD on interlaced sources. Output looks a little blurry, but I always attributed this to a bad source. They are tipically old movies. I'll check on it the next time one of those come to my hands. Thanks for the tip.

[Wilbert]

separateifields.resize(halfheight).weave()

resizing, which completely destroys the spatial detail and introduces a wrong spatial alignment to the fields.
Could you elaborate? What do you mean with "wrong spatial alignment to the fields" and what do you mean with "destroys the spatial detail" (the latter in comparison with progressive resizing)?

[Kika]

Have a look at this thread:


http://forum.doom9.org/showthread.php?s=&threadid=74906&highlight=interlaced