Avisynth: Decomb Plugin for Avisynth Tutorial

nicksteel · #1 02-19-2005, 08:26 AM

Quote:

AviSource("your_clip.avi")
Telecide(order=1,guide=1,post=3,vthresh=25,show=tr ue)

Serve this into VirtualDub and play through the clip while examining frames and the displayed vmetric values. The value that applies to the frame as matched is the one in brackets that starts with "chosen=", e.g., "[chosen=27]". Let's just call that the vmetric value. Any vmetric value greater than vthresh defines the frame as interlaced. You want to find the vthresh value that correctly distinguishes combed frames from non-combed frames for your clip. You'll easily be able to identify the frames thought to be combed because a) the vmetric value will be greater than vthresh, b) the progressive/interlaced indicator will say interlaced, and c) the frame will have a white deinterlacing motion map overlayed on it. There's no way you'll miss them!

TV capture of "Courage the Cowardly Dog".

Trying to determine vthresh value by serving this into Vdub.

The capture is inpattern and all frames above the vthresh value are shown as interlaced with white deinterlacing motion map. Frames below the vthresh value are shown as progressive depending upon the vthresh value used. How do I select the optimum vthresh value if all frames below the vthresh value are shown as progressive regardless of the value I choose?

I just can't figure out how to use this.

fabrice · #2 02-21-2005, 01:02 AM

Hi,

The optimum value is the one that correctly deinterlace interlace frames, and don't find combed zone, where they don't exist...

Salu2
Fabrice

nicksteel · #3 02-22-2005, 09:48 AM

Maybe I am not being specific enough.

I have a 29.97 analog capture that shows interlaced frames. Most of it is in pattern. I am trying to use DecombTutorial to arrive at the correct vthresh value in:

Telecide(order=1,guide=1,post=3,vthresh=31,show=true)

I have a frame that shows:

vmetrics: 35 32 207 [chosen=32]. It shows white deinterlacing motion map and [interlaced] [out of pattern]. (I understand the out of pattern).

I change to:

Telecide(order=1,guide=1,post=3,vthresh=32,show=true)

Frame now shows:

vmetrics: 35 32 207 [chosen=32]. It shows no white deinterlacing motion map and [progressive] [out of pattern]. (I understand the out of pattern).

Obviously, the vthresh value deinterlaces all frames with chosen<=vthresh and renders them progressive. Any vthresh value for this frame >=32 deinterlaces.

How do I determine the optimum vthresh value for all frames.

The [chosen=] varies from 16 to 125 for a set of frames as I step through.