IVTC choppiness on distant objects and dark scenes only?
 

Hope someone here can assist me. I'm having a very frustrating time with a VHS to DVD conversion. The source avi file appears to follow the 3:2 pattern and when I encode it in TMPG using the KDVD template (or even the default NTSC DVD template in TMPG) some scenes with people in the background or that are very dark are choppy. The majority of the mpg looks great...or as great as a VHS cap can look. I've tried increasing the bitrate to 8000 with CQ=100, but it doesn't help.

Here is the script:

AVISource("d:\Video\Capture\Clip0001.avi")

LegalClip()
Trim(1192,159154)
Telecide()
Decimate(cycle=5)
FadeIn2(30)
FadeOut2(30)
Crop(20,2,-4,-4)
BilinearResize(352,474)
PixieDust()
Blockbuster(method="noise", variance=.5, seed=1)
LegalClip()
AddBorders(0,3,0,3)

I've also tried:
Telecide()
Decimate(mode=1)
FieldDeinterlace()

Still choppy.

If I don't do any field processing and encode interlaced @ 29.97, the choppiness is gone, but the overall quality is not nearly as sharp or clean as with IVTC.

Any ideas?

Thanks for your consideration.

Hi hudsonhawk,

Is the choppiness seen on your software player, or only on your standalone?
If it's on your standalone, It could be your DVD authoring software :idea:

-kwag

Hi Kwag,

Thanks for the reply.

Actually, it's on both.

Then the problem is the captured source :!:
Maybe dropped frames :?:

Try just Telecide() and Decimate() without parameters.

-kwag

Here's my 2 cents:

I don't know what your mean by "choppyness" but:

If choppyness is "blocks" , then I put my money on Pixiedust. Pixiedust can produce blocks in areas of a frame that are fast moving. (i.e. looking out the window of a moving car) To check this, load your AVS into Virtualdub and single frame advance through the bad scenes.

If you are seeing non smooth panning then:

If you captured at XXX x 480 use IVTC.

Edit: The blocks problem has been isolated to either my DVD player or Lanczos3Resize NOT Pixiedust.

Hmmm, you know, I had the file open in VDub to check the 3:2 pattern, but never thought to check for bad frames. Thanks for the tip. However, I capture with Scenalyzer Live and that tells me if any frames were dropped during capture, but I suppose it doesn't hurt to check. I will also try decimate without parameters...I think I already did but then again I've done so many tests over the past few days that I can't make sense out of my own notes anymore.

What do you think of GreedyHMA? I was thinking of trying that next, but to deinterlace instead of IVTC. I was hoping decimate(mode=1) would work, but unfortunately I got the same results. Could the problem be with Telecide()? Tis a frustrating problem indeed, but it's great to have a cool resource such as kvcd.net available!

Thanks!

Thanks for the input Mr Tibs.

By choppiness I mean robot like (an arm that doesn't move up smooth but jumps quickly). Basically like it skipped a couple of frames.

I did suspect PixieDust but I encoded one of the choppy scenes with no filters except for telecide and decimate and got the same results.

Actually non smooth panning is a good way to describe how it looks when I encode straight interlace with no field processing. I've been having a hard time describing it..thanks! Interlaced it's not choppy, but not smooth either. I've been attributing this to possibly interlacing artifacts or too many frames. So when you say IVTC, are you referring to the IVTC filter for Avisynth rather than Telecide and Decimate?

I mean the IVTC filter for Avisynth. I found that when I captured at 352x240 telecide and decimate worked best but when I captured at 352x480, IVTC works best.

If you think that noise is causing the problem then try the Interlaced smoothing function found on the Avisynth site: (http://www.avisynth.org/index.php?pa...lacedSmoothing)

You could pre-smooth before doing your pulldown.

MrTibs:

Thank you for the suggestions! I will give them both a try this evening.

I managed to resolve 98% of the choppiness with GreedyHMA:

AVISource("d:\Video\Capture\Clip0001.avi")

Trim(1192,159154)
#Trim(58313,59536) # test clip
GreedyHMA(1,0,4,0,1,0,0,0) # Auto
# Telecide()
# Decimate()
LegalClip()
FadeIn2(30)
FadeOut2(30)
Crop(20,2,-4,-6)
BilinearResize(352,472)
PixieDust()
Blockbuster(method="noise", variance=.7, seed=1)
AddBorders(0,4,0,4)
LegalClip()

There were a couple of brief instances of non-smooth motion, and usually in dark scenes, but not enough to be annoying and not nearly as many as before. The finished product turned out very clean and smooth considering the source. GreedyHMA does an excellent job, at least with noisy VHS anyway.

Thanks again for your assistance!

Nicksteel:

Yes, GreedyHMA would serve the same purpose as telecide() and decimate(). I am finding that with noisy VHS sources at 352x480, GreedyHMA is a little better at reducing choppiness, which seems to occur because of the noise. However, if your source is DVD, you should try both methods and see which works best for you.

Hope this helps.

Looking at the manual, it should read: GreedyHMA(1,0,4,0,0,0,0,0) for automatic.

-kwag

Hi Kwag:

True, but it's still automatic, that last '1' in the 5th column is the vertical filter, the '4' is what makes it automatic.

:oops: Thanks :!:

-kwag