Filter to average every N frames?

[D9JK]

Hello,

Is anyone aware of a filter that averages (the entire contents of) every N frames in a clip?

For example:

"AverageFrames(30)" would take the first 30 frames and create a single, averaged frame out of them, and then move on to the next 30 frames. And so on. In this case, the total clip length is of course reduced to 1/30.

To further clarify, "AverageFrames(2)" would be similar to:

A = Clip.SelectEven()
B = Clip.SelectOdd()
Merge(A,B)

But how to do this efficiently for, say, every 30 frames?

[Reel.Deel]

Have you looked at AvgAll or ClipBlend?

[StainlessS]

Dont think ClipBlend would suit, ClipBlend can output average of previous 30 frames with same o/p as i/p frame count.
If you jump about in the stream [eg SelectEvery(30,29)] then it will 'reset' itself (throw away accumulated ave data)
and start accumulating again, so for every output frame it would reset accumulator and would be no different to a simple SelectEvery(30,29).
You could however do it in two passes

AviSource("d:\1.avi")
ClipBlend(Delay=30-1)

AviSource("d:\2.avi")
SelectEvery(30,29)

Untested but should work I think.

EDIT: "average of previous 30 frames" should read "average of previous 29 + current frames".

[StainlessS]

This seems to (EDIT: does) work but conversion to RGB, EDIT: but ODD number of averaged frames only

# Temporal Average of 29 frames

avisource("D:\avs\test.avi")
ConvertToRGB24()
RgbAmplifier(Radius=15,Multiplier=0.0)		# Radius * 2 - 1 frames averaged (14 before, 14 after + current)
SelectEvery(29,14)

http://forum.doom9.org/showthread.ph...t=RGBAmplifier

[D9JK]

Sounds good, I'll give it a try. :-)

Thanks to both of you for your help!

[colours]

Why not just use TemporalSoften?

It'll have the same limitation of only working when N is odd, but works on YUV too. Or actually, requiring that N is odd isn't too hard to work around…

function blend(clip c,int n)
{
	if (n%2 == 0)
	{
		blended = c.temporalsoften(n/2-1,255,255,255,2).selectevery(n,n/2)
		return merge(blended,c.selectevery(n,0),1.0/n)
	}
	if (n == 1) {return c}
	return c.temporalsoften((n-1)/2,255,255,255,2).selectevery(n,(n-1)/2)
}

Needs Avisynth+ for the if statement goodness. (TemporalSoften can also be replaced by RgbAmplifier if you so desire, of course.)

[Gavino]

Originally Posted by colours

Needs Avisynth+ for the if statement goodness.

Or GScript of course.

[creaothceann]

Alternatively:

Originally Posted by colours

function blend(clip c, int n)  {
	(n % 2 == 0) ?	Merge(	c.TemporalSoften( n      / 2 - 1, 255, 255, 255, 2).SelectEvery(n,  n      / 2), c.SelectEvery(n, 0), 1.0 / n)
  \:	(n     != 1) ?		c.TemporalSoften((n - 1) / 2    , 255, 255, 255, 2).SelectEvery(n, (n - 1) / 2)
  \:				c
}