I have been asked to fix this video, but have not yet received the DVD. It is of a 1945 American football game. I don't have access to the original film, but I was told that the original film to video transfer was done professionally. Whatever created these horizontal bars happened after that time.
I have been told that they are static (i.e., they do not crawl up or down the screen as the video is playing).
Question 1: does anyone know what this interference pattern might be called (so I can Google it)?
Question 2: does anyone have some general ideas of what they would use to fix it? If they truly are static, then I might just be able to get away using a mask of some sort and then adjust the exposure and color saturation. If they move, I'll have to devise another approach.
Question 3: Does anyone know what might have caused this?
I ask the last question because the person who purchased this disc may be able to find a source that is closer to the original transfer if we can pinpoint what caused the problem, and by knowing that, figure out how to go around the person involved.
Here's an unedited clip from the DVD:
Noise Bar Clip
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Last edited by johnmeyer; 9th Apr 2021 at 16:58. Reason: added link to clip
Hum bars. The can be reduced by a lot in AviSynth:
[Attachment 58299 - Click to enlarge]
ImageSource("nUPErnm.png", start=0, end=23, fps=23.976) src=last ConvertToYV12() # image has already been deinterlaced? BilinearResize(720,480) # assuming the original was 720x480, NTSC DVD. TurnRight() defreq(fx=16.6, fy=0.0, dx=2, dy=2, sharp=0, info=false, show=0) defreq(fx=49.4, fy=0, dx=2, dy=1, sharp=0, info=false, show=0) TurnLeft() aWarpSharp(depth=5).Sharpen(0.3) Spline36Resize(src.width, src.height)
johnmeyer, when you get the DVD upload a sample and I'll update the script.
The image is (or will be by the time I do IVTC) progressive.
You got a great result. Your approach is similar to what I was going to initially try, given that I've used Defreq before.
I have two questions.
1. I've never resized to the same resolution. You then perform a second resize, also to the same resolution, as the last step. I'm sure you did this for a reason. What does it do?
2. Since you can specify the angle and spacing in Defreq, why the Turnright/Turnleft?
I would have just done the Defreq and gone home.
P.S. When you say "subtracting them," are you talking about a mask? I was thinking of doing a blur and using the result for a mask.
Last edited by johnmeyer; 8th Apr 2021 at 00:49. Reason: typo
TurnRight() defreq(fx=16.6, fy=0.0, dx=2, dy=2, sharp=0, info=false, show=0) defreq(fx=49.4, fy=0, dx=2, dy=1, sharp=0, info=false, show=0) TurnLeft()
defreq(fx=0.0, fy=16.6, dx=2, dy=2, sharp=0, info=false, show=0) defreq(fx=0.0, fy=49.4, dx=2, dy=1, sharp=0, info=false, show=0)
I now understand the resize and I probably won't need to do that either, since the results of my effort will go right back onto another DVD (that's the deliverable).
santiag(strv=0, nns=4) will probably help clean out the leftovers. I see what looks like really tiny lines left over that look like leftover interlacing artifacts, even if its not interlaced. Santiag usually masks or removes those pretty well most of the time.
I can guarantee that any temporal issues between fields will be gone before I start doing anything (I know how to IVTC or deinterlace), and so I will be working on progressive film frames.
Here's an unedited clip from the DVD:
Noise Bar Clip
I found that the last two minutes of the DVD is a blank screen (the film had run out) which included the noise bars. It provides a hint as to what caused the problem. I note that the bars are not horizontal and that they jitter up/down slightly. I've attached a snapshot of the bars.
I'll post my results, after I try a few of the suggestions.
Last edited by johnmeyer; 10th Apr 2021 at 09:24. Reason: changed "tape" to "film"
Yes, I noticed the bars weren't perfectly horizontal too. Earlier I had taken an image of the bars at the far right of the frame, stretched it to the full image width, then subtracted it. Here's what I got:
[Attachment 58341 - Click to enlarge]
You can see that it worked pretty well at the right half of the frame but failed at the left. You're bar image shows why.
Last edited by jagabo; 9th Apr 2021 at 17:20.
Yes, I'm working on that now. Using the bars as a mask is close, but no cigar.
Also, the clip must be IVTC'd before you can do anything. It's just standard 3:2 pulldown.
I used jagabo's Defreq script (without the resize, since that's not needed) and it's pretty darn good. I'll try seeing if I can tune it a bit, using the secondary Defreq parameters. Once I eliminate all the white flashes at scene changes (all movie cameras do this), run it through my film restoration script, and adjust the exposure, it should look pretty good.
The one problem is that there Defreq seems to fail fairly often on the top 10% of the frame. There is also some residual from the bars up and down the center of the frame, but I think that is due to the bar's discontinuity at that point. This will probably be good enough for this project, unless someone has a few tweaks to suggest. I'll post a before/after in a few days when I'm finished.
Last edited by johnmeyer; 9th Apr 2021 at 20:36.
the filter destripe was made to take care of these stripes http://avisynth.nl/index.php/DeStripe
avisource() # ivtc'd
edit: nevermind defreq works better it seems
Last edited by themaster1; 10th Apr 2021 at 06:20.
Last edited by killerteengohan; 14th Apr 2021 at 15:48.
Yes, one often gets those slight comb-like artifacts after IVTC of hard telecined material. They occur because compression artifacts cause small differences between the matching fields, especially when the two fields come from different video frames. I've always used vInverse() to eliminate them but your santiag(strv=0, nns=4) seems to work better in a few quick tests I ran.
I finished the project. Thanks jagabo for your Defreq settings. I tried to improve on them but, once again, failed to figure out how to use the "show" information to tune the parameters. Once in awhile, when I've used Defreq in the past, I hit the right numbers, but it isn't just as easy as looking at the on-screen numbers and then putting them into the appropriate Defreq settings.
I was going to upload my "after" but it was essentially what jagabo already posted, although with some additional fixes, like gamma correction, stabilization, and a little dirt removal. Since I ended up using jababo's code, without alteration, there is nothing new to show regarding the removal of the bars.
Last edited by johnmeyer; 13th Apr 2021 at 16:55.
Since I did do a few other things, here is the "before/after."