AviSynth: script command, order of execution, and 'coding efficiency'

[hollowman]

Is the order of the individual scripts within a single AVS file important (and/or WHEN is it important, and when not)?

E.g., in the script-file below, is there a possibly better order to the script commands? It, and others like it seem to run fine. But being a newbie, I may be missing out on ouptut quality or, at least, processing-time efficiency.

loadcplugin("c:\program files\avisynth 2.5\plugins\yadif.dll")
video = AviSource(".06-06-01_18-06.00.avi")
audio = WavSource("Symphony-2-Op 19-Andante-Un-Poco-Mosso.wav")
# combine them into a single clip
AudioDub(video, audio)
converttoYUY2(interlaced=true)
crop(0,50,0,-50)
Yadif()
LanczosResize(640,360)
FadeIO0(30)

[manono]

You want to filter in the native colorspace (YV12, I'm assuming) and stick the ConvertToYUY2() at the end of the script. By that point it's no longer interlaced.

And does this AVI really need deinterlacing? What kind is it?

[hollowman]

You want to filter in the native colorspace (YV12, I'm assuming) and stick the ConvertToYUY2() at the end of the script. By that point it's no longer interlaced.

Thx for your reply.

Dunno WHY files my WinDV-captured AVI files (from an NTSC miniDV camcorder) don't like AviSynth. Using Canopus Let's Edit software to capture from the camcorder presents no problem with AviSynth.

Specifically, when opening an AVS script in VirtualDub or VDM -- on that points to a WinDV-captured AVI file -- I get an error:

"AviSynth open failure: Video must be YUV"

To resolve this issue, I had to add the above-noted line:

converttoYUY2(interlaced=true)

Is this "solution" a compromise in some way?

(Note: I can open the file in VD or VDM w/o using AviSynth)

And does this AVI really need deinterlacing? What kind is it?

It makes a visible difference, and Yadif is better than any VDM deinterlacing plugin I know of.
BTW: The target output is an x264 AVI file. I use VDM to do this.

[Jim44]

Dunno WHY files my WinDV-captured AVI files (from an NTSC miniDV camcorder) don't like AviSynth.

WinDV transferred DV-AVI files work just fine with AviSynth (I do it all the time) - depending on what you have in your script.

"AviSynth open failure: Video must be YUV"

From the info page for Yadif (http://avisynth.org.ru/yadif/yadif.html):
"YUY2, Planar YV12 color format only."
It would appear that it's your use of Yadif that is creating the error. But I've only tinkered with deinterlacing - I'd have to check if I saved a Yadif script to see if I had to convert color space.

Hope that helps,
Jim

[hollowman]

It would appear that it's your use of Yadif that is creating the error.

Bingo!
I removed Yadif() and the file opened fine.
I do need good deinterlacing, like Yadif, but I'm not sure if using converttoYUY2(interlaced=true) and Yadif() is the best option if converttoYUY2(interlaced=true) is compromising my output in some other way.

[manono]

Then my first reply was off the mark. I was assuming some sort of XviD/DivX AVI. OK, first, what is the colorspace, RGB? I know nothing about DV AVI. To find out, stick:

Info()

temporarily at the bottom of an otherwise unfiltered script. You should then add:

ConvertToYV12(Interlaced=True)

before doing the Yadif deinterlace. That way you can use Fast Recompress in VDub and already have it converted to the final colorspace (thus preventing more colorspace conversions). There may also be color matrix considerations, but that's more jagabo's speciality than mine. Is it a compromise? All colorspace conversions are compromises, but they sometimes have to be done, and doing it properly will minimize the small amount of damage.

[hollowman]

manomo/All:

I solved the issue thx to Derek on YouTube:
http://www.youtube.com/watch?v=JkQDuqZaQAI

He also suggested using "ConvertToYV12()", as several of you have, and when that produced a VDM Warning -- "Couldn't locate decompressor for Y12 (unknown)..." -- he said try the following (Helix YUV Codecs):

http://free-codecs.com/download/Helix_YUV_Codecs.htm

This cured the glitch.

ColorSpace before was YUY2, now it's YV12.