please help a cat, IResize need yadif before?

[marcorocchini]

Hi ****,

please consider a interlaced video file 1920x1080
I need resize to 720 x 576 using IResize

What script is correct?
This:

FFVideosource("input.mxf")
yadif(1,1)
IResize(720,576)
AssumeTFF().SeparateFields().SelectEvery(4, 0, 3).Weave()

or this:

FFVideosource("input.mxf")
IResize(720,576)

or others?

function IResize(clip Clip, int NewWidth, int NewHeight) {
Clip
SeparateFields()
Shift=(GetParity() ? -0.25 : 0.25) * (Height()/Float(NewHeight/2)-1.0)
E  = SelectEven().Spline36resize(NewWidth, NewHeight/2, 0,    Shift)
O  = SelectOdd( ).Spline36resize(NewWidth, NewHeight/2, 0,   -Shift)
Ec = SelectEven( ).Spline36resize(NewWidth, NewHeight/2, 0,  2*Shift)
Oc = SelectOdd( ).Spline36resize(NewWidth, NewHeight/2, 0, -2*shift)
Interleave(E, O)
IsYV12() ? MergeChroma(Interleave(Ec, Oc)) : Last 
Weave()
}

also even if I have to upscale? thanks

thanks

[poisondeathray]

IResize is for interlaced scaling, typically HD=>SD, so yadif isn't required , just the colormatrix adjustment

[jagabo]

And IResize() is a crappy resizing filter.

[marcorocchini]

and for upscale interlaced source is there a better deinterlacer?

[poisondeathray]

And IResize() is a crappy resizing filter.

What makes you think that ?

[jagabo]

Looking at its results.

source:


IResize(720,576):


Yadif(mode=1).BilinearResize(720,576).SeparateFiel ds().SelectEvery(4,0,3).Weave():

[poisondeathray]

That's pretty clear evidence on a static test pattern.

Iresize was written by Gavino specifically for interaced HD=>SD on difficult alias prone footage.

Compare it on this real footage, "pattern from hell" test clip (it was originally from the sony vegas forum, with long discussion on interlaced handling etc....)

I've tested various methods , HD2SD, the typical resize methods, +/- various lowpassing etc... there is one clear "winner" on this sample

[jagabo]

The results of test pattern tell you what to look for in real world video. Sharp near horizontal edges will develop the same problems in any video. But yes, difficult to deinterlace video will result in other problems.

[poisondeathray]

The results of test pattern tell you what to look for in real world video. Sharp near horizontal edges will develop the same problems in any video. But yes, difficult to deinterlace video will result in other problems.

I agree, and there are drawbacks for every method

That's why I suggested in his previous threads to use IResize for what it was written for, not general purpose use for everything

I specifically use IResize only on sections that need it . Not all footage has sharp edges, or sometimes footage is very soft to begin with. Just like low passing static sections will degrade it unnecessarily

[newpball]

...sometimes footage is very soft to begin with.

I dare saying that SD footage (from real images not animations or digital art) is always somewhat soft, as it should be!

If it is shows sharp lines chances are it is butchered by excessive sharpening.