DotCrawl filter on VHS Video shows blotches during play back.

[mlong30]

Hi,

I'm using the DotCrawl filter on a old VHS tape, that I copied, and I noticed these little blotches in the video during play back on my new Plasma TV. Is this normal or is there anyway for me to prevent it?

http://www.lwintegrationtest.com/DotCrawl.jpg

Thanks.

[jagabo]

What dot crawl filter? And, no, it's not normal.

[mlong30]

DotCrawl Comb Filter by Scott Elliott
I'm just using the default settings.

[jagabo]

Can you upload a short video sample -- before any filtering?

[themaster1]

i would rather call this "missing chroma"

[sanlyn]

Probably referring to this VirtualDub filter: http://home.earthlink.net/~tacosalad/video/dotcrawl.html
Some notes in the site about splotches, ghosts, etc.

[jagabo]

I'm pretty sure I've seen similar problems with that filter before. I think it's a bug in the filter. It hasn't been updated since 2003.

[sanlyn]

In Avisynth you might try UnDot or TComb. I've also known VirtualDub's temporalsmoother to help with dot crawl a bit, but not if the dot crawl never moves very much in the image.

[mlong30]

Can you upload a short video sample -- before any filtering?

http://www.lwintegrationtest.com/Test_Lsu.avi

[sanlyn]

Can you upload a short video sample -- before any filtering?

http://www.lwintegrationtest.com/Test_Lsu.avi

Has this sample already been filtered, or are you referring to the high-compression/low-bitrate artifacts, the macroblocks, the jaggies, or the smeared details?.

[jagabo]

Is that a sample of the original video? It has a lot of macroblock artifacts (maybe from digital broadcast?). And why isn't it interlaced? I can't duplicate the problem with Dot Crawl here. What settings were you using? Did you use some other filters too? And I don't see dot crawl artifacts in that sample.

[mlong30]

Can you upload a short video sample -- before any filtering?

http://www.lwintegrationtest.com/Test_Lsu.avi

Has this sample already been filtered, or are you referring to the high-compression/low-bitrate artifacts, the macroblocks, the jaggies, or the smeared details?.

No this video hasn't been filtered.

[mlong30]

Is that a sample of the original video? It has a lot of macroblock artifacts (maybe from digital broadcast?). And why isn't it interlaced? I can't duplicate the problem with Dot Crawl here. What settings were you using? Did you use some other filters too? And I don't see dot crawl artifacts in that sample.

I see the splotches at frame 143-144, with the guy who has the ball. My settings are the default.

[sanlyn]

Hm. I don't see any dot crawl in that sample.

[sanlyn]

I see the splotches at frame 143-144, with the guy who has the ball. My settings are the default.

Maybe you submitted the wrong video? No dot crawl, no splotches. If splotches are there, they don't look like those in the image you posted earlier.

[mlong30]

Hm. I don't see any dot crawl in that sample.

I see it all over. Here is a snapshot of what I see in this sample.

http://www.lwintegrationtest.com/splotches.jpg

I use the control where the arrow is pointing too, by sliding back and forth. Maybe my file is corrupt. I'll try to download another copy to see if that fixes the issue.

[jagabo]

After the Dot Crawl filter I see some small blotches like the small ones in your first sample image. No big blotches though. The temporal portion of the filter is causing the little spots. Disabling the temporal portion will eliminate the problem. But I don't see why you're using this filter at all.

[poisondeathray]

This might be a vdub setting, like low bit depth or your graphics overlay is using low bit depth


options => preferences => display => uncheckmark use direct x for display panes

[sanlyn]

Hm. I don't see any dot crawl in that sample.

I see it all over. Here is a snapshot of what I see in this sample.

http://www.lwintegrationtest.com/splotches.jpg

That's frame 141 of your sample. Did you notice that the frame is filled with reflections from a camera's electronic flash? The flash lasts for 2 frames and appears to be off-scene to the left. Look at the shadows on the floor.

[mlong30]

After the Dot Crawl filter I see some small blotches like the small ones in your first sample image. No big blotches though. The temporal portion of the filter is causing the little spots. Disabling the temporal portion will eliminate the problem. But I don't see why you're using this filter at all.

Thanks, disabling the Temporal Comb Filter resolved my issue.

[mlong30]

But I don't see why you're using this filter at all.

Do you think I should be using any other filters for this particular video?
I may just use neat video to reduce the noise by 20% on this video.

[2Bdecided]

I don't think this needs dot crawl removal.

It didn't needed blend deinterlacing either, but that seems to be what's happened to it.

Cheers,
David.

[sanlyn]

NeatVideo won't help. At default, which is the way most people mis-use NeatVideo, it will denude what's left of the movie. Your sample shows signs of previous filtering, as there is little grain or streaking, etc. I believe the "noise" you refer to was 100% caused earlier by inappropiate lossy compression (which occurred a long time before this video ever saw Lagarith), a bitrate far too low for fast action video, and improper deinterlacing. NeatVideo might be able to (slightly) smooth some edges, which basically means making the sharp jaggies look like smoother jaggies, but distinct jaggies nevertheless. It will destroy detail in the clothing, faces, and the polished wood detail of the playing floor, unless NeatVideo's Y-channel filtering is tuned almost all the way off, because all of these elements appear to have been filtered earlier. It won't do anything for the motion artifacts, mosquito noise, or edge ghosting.

[jagabo]

I wouldn't bother filtering this video. But try a deblocking filter too. In AviSynth:

import("C:\Program Files (x86)\AviSynth 2.5\plugins\deblock_qed.avs")

AviSource("Test_Lsu.avi")
ConvertToYV12()
Deblock_QED()
UnDot()
McTemporalDenoise(settings="medium")

x264 mkv attached.

[mlong30]

I don't think this needs dot crawl removal.

It didn't needed blend deinterlacing either, but that seems to be what's happened to it.

Cheers,
David.

I think you maybe on to something here. Normally all my basketball videos are on VHS tape, that I recorded. Now I remember this particular video, was given to me already converted to DVD/VOB. I believe the guy used a DVR to DVD or something.

1. I took the VOB files and opened it using MPEG2 converter using Virtual Dub.
2. Save it back out using the Lagarith.
3. I then opened the avi file using Sony Vegas Pro 10, to delete 20min of commercials. Seemed easier to edit in Vegas versus Virtual Dub, because the audio was compress and virutal dub wouldn't play it the audio back.
4. Then saved the final results back using Lagarith to avi, using the following project settings...
http://www.lwintegrationtest.com/projectsettings.jpg

Where did I mess up, in my work flow?

Thanks!

[sanlyn]

I wouldn't bother filtering this video. But try a deblocking filter too. In AviSynth:

import("C:\Program Files (x86)\AviSynth 2.5\plugins\deblock_qed.avs")

AviSource("Test_Lsu.avi")
ConvertToYV12()
Deblock_QED()
UnDot()
McTemporalDenoise(settings="medium")

x264 mkv attached.

Shucks, jagabo. Ya beat me to it again. I should have got outta bed earlier. I'm running something similar but added some anti-alias (didn't help that much, but helped) and chroma cleaning.

The color histogram is a mess.

[jagabo]

Install AC3ACM decoder and you can listen to the VOB audio in VirtualDub. Then you can skip the Lagarith and Vegas steps. Be sure to force the colorspace to YUY2 when opening MPEG files in VirtualDub. Otherwise VirtualDub will screw up the chroma.

[mlong30]

Install AC3ACM decoder and you can listen to the VOB audio in VirtualDub. Then you can skip the Lagarith and Vegas steps. Be sure to force the colorspace to YUY2 when opening MPEG files in VirtualDub. Otherwise VirtualDub will screw up the chroma.

What should be the field order be? Sometimes I can't trust Gspot.

[jagabo]

What should be the field order be? Sometimes I can't trust Gspot.

Add the Bob Doubler filter and step through the fields. If you get jerky back and forth motion you picked the wrong field order.

[sanlyn]

I don't think this needs dot crawl removal.

It didn't needed blend deinterlacing either, but that seems to be what's happened to it.

Cheers,
David.

Agreed.

I think you maybe on to something here. Normally all my basketball videos are on VHS tape, that I recorded. Now I remember this particular video, was given to me already converted to DVD/VOB. I believe the guy used a DVR to DVD or something.

1. I took the VOB files and opened it using MPEG2 converter using Virtual Dub.
2. Save it back out using the Lagarith.
3. I then opened the avi file using Sony Vegas Pro 10, to delete 20min of commercials. Seemed easier to edit in Vegas versus Virtual Dub, because the audio was compress and virutal dub wouldn't play it the audio back.
4. Then saved the final results back using Lagarith to avi, using the following project settings...
http://www.lwintegrationtest.com/projectsettings.jpg

Where did I mess up, in my work flow?

Thanks!

1. VOB/DVD is already MPEG2. Usually, just change the file name.
2. Use DGIndex to convert to YUY2 AVI/Lagarith and save the audio as uncompressed PCM\WAV.
3. You are cutting compressed video and compressed audio, adding to artifacts and color problems.

Do your filtering and other work in AVI first, not in compressed MPEG. Then go to RGB if needed. I worked in YUV.

The video has a strong purple color cast, difficult to get rid of. I did a bit of color work, but you'd need advanced controls in Vegas to clean the color. Edit after you make corrections. I worked mostly on noise, ghosts, etc.: