Why is resizing so much slower in AVIsynth than Vdub?

[Stereodude]

I deal with HDTV res files (1920x1080) primarily and for various reasons I prefer to resize (bicubic or Lanczos) in RGB rather than AVIsynth 2.07's native YUY2 mode. Resizing in YUY2 in AVIsynth is rather peppy, but if I ConvertToRGB() first, then do a resize it's about 4x as slow as Vdub using the same resizing method. Is VirtualDub just that much better optimized? or am I doing something wrong?

Stereodude

[dividee]

Are you sure it's the resize that's slower? Did you time ConvertToRGB vs vdub/Full processing, without resize ? ConvertToRGB is probably slower than vdub internal conversion, as the former assumes the chroma sample is aligned with the left luma sample, while the latter assumes the chroma sample is between the luma samples, which is easier to code.

[Stereodude]

Originally posted by dividee
Are you sure it's the resize that's slower? Did you time ConvertToRGB vs vdub/Full processing, without resize ? ConvertToRGB is probably slower than vdub internal conversion, as the former assumes the chroma sample is aligned with the left luma sample, while the latter assumes the chroma sample is between the luma samples, which is easier to code. You may be right. It is however some combination of the two filters I guess.

Stereodude

[WarpEnterprises]

The AviSynth speed in general seems quite dependend on the final image size (at least on my system).
Take care to get this (the data transfer AviSynth -> App) out of your measurements.

[sh0dan]

@Stereodude:

Could you post your setup and scripts? Input, output, codecs, programs, versions, etc.

What's your exact times?

[Stereodude]

Slow Version:LoadPlugin("c:\mpeg2dec\MPEG2DEC3.dll")
LoadPlugin("c:\decomb\decomb.dll")
mpeg2source("i:\leno\D45-1221-0026.d2v",cpu=4,moderate_h=40,moderate_v=80)
SeparateFields()
SelectOdd()
Crop(4, 0, -6, -6)
ConvertToRGB()
BicubicResize(720,480)I load this into Vdub and save it to a HuffYUV compressed AVI.

Fast Version:LoadPlugin("c:\mpeg2dec\MPEG2DEC3.dll")
LoadPlugin("c:\decomb\decomb.dll")
mpeg2source("i:\leno\D45-1221-0026.d2v",cpu=4,moderate_h=40,moderate_v=80)
SeparateFields()
SelectOdd()
Crop(4, 0, -6, -6)I load this into Vdub, do a Precise Bicubic (.75) to 720x480 and compress to a HuffYUV AVI.

The source is a mpeg-2 of HDTV (extracted from a transport file) at 1920x1088 from NBC. I'm running AVIsynth 2.07, the latest Vdub (1.4.13).

Stereodude