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19th May 2004, 15:44 | #1 | Link |
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Processing Interlaced Source as Progressive
Hi,
Before someone ask , yes, I'm talking about a interlaced source, since I'm capturing NTSC cartoons directly from my cable tv. But I don't know if it's true interlaced or not... What I'm trying to do is avoid, at any costs, the shimmering around the edges from the encode. It's always something very anoying to me. I tried all kinds of Decomb configurations, but I heard that deinterlace is not perfect. So, I decided not to use it. I'm processing the video like I did before, only without Telecide... LoadPlugin("xxx") Avisource("d:\xxx.avi").ConvertToYV12() Decimate() Spatial_Filter() Temporal_Filter() Spatial_Filter() LanczosResize(480,360) Limiter() ColorYUV(levels="PC->TV") I was expecting to see that "interlaced effect" on moving parts. But when I resize the source to 480x360 (the source is 720x480), playing the video, it's not really possible to see this effect. It's there. But it's possible to see only looking frame by frame on VirtualDub. However, if I don't resize and keep the 720x480, the effect is very visible. So, my question is: is there any real bad effect to "deinterlace" using this method instead of the real deinterlace (using Telecide) ? If no, this is the correct way to do this ? Another question... What kind of filter or method I could use to reduce (or maybe eliminate) the shimmering around the edges ? Anything. What kind of resize is better for this task (LanczosResize or Bicubic), and so on...anything. Thanks! |
20th May 2004, 00:15 | #2 | Link |
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>But I don't know if it's true interlaced or not...
You can't make processing decisions without knowing the nature of your source material! You're just groping in the dark. Your post shows several misconceptions also. I suggest that you post a link to a small *unprocessed* source clip for us to inspect. We'll then tell you how it should be processed and how we arrived at the conclusion. You'll learn a lot from it. |
20th May 2004, 01:38 | #3 | Link |
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Well, let me know if this raw sample is good enough...
http://geocities.yahoo.com.br/vigi_lante/mjpeg.avi 5mb Last edited by vigi_lante; 20th May 2004 at 04:53. |
20th May 2004, 03:53 | #4 | Link |
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I'm following Decomb manual, but I'm still trying to set the correct Post Processing value...
Take a look... So, what Telecide does is take this frame, that is called interlaced... Pic1 (maybe you need to copy and paste into the broswer) ...and transform into a progressive frame, that don't have this comb effect. The manual say that I need to use this script... AviSource("d:\box\caverna.avi") Telecide(order=1,guide=1,post=3,vthresh=30,show=true) ...to set the correct post processing value. What I need to do is find a correct value that will tell decomb: "you need to deinterlace frame 1361, but not 1362". Is that right ? Now, take a look at this picture... Pic2 (maybe you need to copy and paste into the broswer) When there is a interlaced frame, I always get high values (100+) in the second vmetric number, and on this frame, the value is "144". Is there any way to configure decomb to deinterlace only the frames that have high values (more than 100) on this second vmetric field ? Because, from what I read on the manual, I need to find a vthresh value that will limit the range of the deinterlace based on the chosen vmetric value... Example... My vthresh is: 60 So, decomb will only deinterlace frames that have a chosen vmetric value that is 60 or more. Is that right ? But the problem is that I have a lot of interlaced and progressive frames that are inside this range. So, how I would solve this problem ? Thanks in advance! Last edited by vigi_lante; 20th May 2004 at 04:24. |
20th May 2004, 04:01 | #6 | Link |
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Next time I'll remember to say a short clip!
You gave me 1500 frames of highly compressed Xvid. Can you give me just a couple hundred frames in HUFYUV? I don't care how big the file is. Pick a section that you are having problems with. I assume that isn't your source clip and you compressed it for upload. Is that right? What is the source material? If it is a VOB you can cut a VOB fragment. Last edited by Guest; 20th May 2004 at 04:06. |
20th May 2004, 04:52 | #8 | Link |
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Done...
Since I have only 15mb of host space. I compressed with mjpeg, but now it will do the job... http://geocities.yahoo.com.br/vigi_lante/mjpeg.avi |
20th May 2004, 05:25 | #10 | Link |
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I processed the clip with this:
loadplugin("d:\don\programming\c++\avisynth\decomb\release\decomb.dll") avisource("mjpeg.avi") crop(0,4,-0,-0) telecide(order=1,post=2,guide=1,vthresh=75) decimate() The results were fine. If you are asking how to set a perfect vthresh, it can't be done. But it is better to catch a few progressives than to let combs through, so err on the side of caution. Really picky people err on the high side and then use overrides to force the stray combs to be deinterlaced. EDIT: I see dot crawl. Are you are using an S-Video connection and not composite? Last edited by Guest; 20th May 2004 at 05:42. |
20th May 2004, 05:46 | #12 | Link |
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This is 3:2 pulldown material, so Telecide matches the fields and produces progressive frames. You don't want to deinterlace those good progressive frames. But for various reasons, sometimes combed frames slip through the field matching and you want just those to be deinterlaced. In the clip you provided there were no stray combs so no deinterlacing had to be done.
There is a big difference between real pure interlaced material and 3:2 pulldown material. There is a very good sticky thread in the DVD2AVI forum about this. Check it out. |
20th May 2004, 06:01 | #13 | Link |
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Oh brother, nothing makes sense...
I will try to find a newbie explanation to understand all this mess...until there, I will trust in your word. Thanks for the help. PS: Do you know which resizer avoid more shimmering around the edges: LanczosResize or BicubicResize ? |
20th May 2004, 06:08 | #14 | Link |
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The edge noise is dot crawl. What kind of cable are you using to connect your signal to the capture card?
Oh, here's a good newbie resource: http://www.100fps.com |
20th May 2004, 06:16 | #16 | Link |
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That's your problem right there. You should look on the back of your cable box and find an S-Video output. Connect that to the capture card, assuming it has an S-Video input. If not, get a better one.
EDIT: Judging by the noisy signal you probably have analog cable and no cable box, in which case you are screwed. Your capture card has a crappy comb filter. Try the Capture forum. Last edited by Guest; 20th May 2004 at 06:22. |
20th May 2004, 06:23 | #18 | Link | |
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20th May 2004, 12:26 | #20 | Link |
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Have a look in the cap guide. However, it's only possible to remove those in static scenes with avs.
Since you are a NTSC guy, you can try http://home.earthlink.net/~tacosalad.../dotcrawl.html It's a vdub filter, but it also removes dot crawls and rainbows from dynamic scenes. |
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