SelectRangeEvery and filtering

[mikenadia]

With no filtering, I have a decrease in speed of 25 % (OK) but with heavy filtering,I have:
with: SelectRangeEvery
Heavy Filtering ( at the end of the avs script)
slight decrease in speed (as expected)

with: Heavy Filtering
SelectRangeEvery ( at the end of the avs script)
The speed is decreased by 2.

Is this normal? In the second case, are all frames filtered and then some of them are selected? And should the results be identical? What happens in both cases when I have some filters using more than 1 frame (FFT3dfilter with bt=3 for example or any temporal).
The avs scripts are generated automatically and are of the second type.

Thanks in advance.

[Gavino]

In principle, SelectRangeEvery should be very fast, as (like Trim, for example) it just selects frames and does not process any pixels. However, the resulting non-linear access can cause the source filter to perform suboptimally, depending on its seek behaviour. What format is your source file and what source filter are you using?

There is a difference between doing SelectRangeEvery before and after a temporal filter.
With SelectRangeEvery first, the filter will see only the selected frames as its input stream. The other way round, the filter sees the original sequence.

SelectRangeEvery will only request the frames it needs from the preceding filter, so the filter is not processing all input frames and then selecting only some of them. However, in its 'temporal' processing (looking at next and previous frames), it will access some frames that are not present in the output.

[mikenadia]

The file is a NTSC DVD processed with DVD_Rebuilder (it uses dgdecode 1.0.0 ).

The avs script ( used for the Extras,therefore, the strong denoising) is:#------------------
# AVS File Created by DVD Rebuilder
# VOBID:01, CELLID:01
#------------------
LoadPlugin("C:\Program Files\DVD Rip Prog\DVD-RB\DGDecode.dll")
mpeg2source("c:\working\d2vavs\v01.d2v")
LoadPlugin("C:\Program Files\DVD Rip Prog\AviSynth 2.5\plugins\FluxSmooth.dll")
LoadPlugin("C:\Program Files\DVD Rip Prog\AviSynth 2.5\plugins\fft3dfilter.dll")
LoadPlugin("C:\Program Files\DVD Rip Prog\AviSynth 2.5\plugins\TTempSmooth.dll")
Fft3dfilter(bw=8, bh=8, ow=4, oh=4, plane=0, bt=1, sigma=3)
Fft3dfilter(bw=128, bh=128, ow=64, oh=64, plane=0, bt=1, sigma=0.375, sigma2=0.75, sigma3=1.5, sigma4=3)
Fft3dfilter(bw=8, bh=8, ow=4, oh=4, plane=3, bt=1, sigma=4)
Fft3dfilter(bw=128, bh=128, ow=64, oh=64, plane=3, bt=1, sigma=.5, sigma2=1, sigma3=2, sigma4=4)
Ttempsmooth(maxr=7)
#ConvertToYV12()
# Frames: 3036
Trim(2, 3033)
# Frames after trim: 3032
SelectRangeEvery(72, 12)
# Frames sampled: 512

Thanks for your help. So if I take out any temporal filter, both scenari should have the same output and similar speed.

Is Temporal only
Spatial only
SelectRangeEvery
equivalent to
Temporal only
SelectRangeEvery
Spatial only

[Gavino]

Is Temporal only
Spatial only
SelectRangeEvery
equivalent to
Temporal only
SelectRangeEvery
Spatial only
Yes, I believe it should be.