Quantcast TBC for video flicker and bounce? - digitalFAQ Forum
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12-11-2014, 10:27 AM
jriker1 jriker1 is offline
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I have rarely, if at all, seen the point of a frame based TBC since putting the Panasonic ES15 in line with my video captures. I do have some footage that still seems to bounce up and down vertically, almost looking like a bouncing camcorder but not really the case, plus occasional screen flicker. From what I know about frame TBC's, I assume it would not fix this problem? I tried my TBC-1000 with the bouncing but didn't seem to make a positive impact, but don't have it with me right now to evaluate the flickering. The flickering looks almost like a singular bounce in the video from time to time. Are there AVISynth tools that can fix the vertical bouncing such as DePanStabilize post capture? Or maybe a Virtualdub filter like: http://guthspot.se/video/deshaker.htm

-- merged --

OK so I have tested three different deflicker methods and impressed overall as the flickering/bouncing can be extensive in the footage. This isn't camcorder bouncing but bad tape:

VideoFred in AVISynth:
Code:
# stabilize by VideoFred (but without deflicker)
requestlinear()
o=last
maxstabH=20 maxstabV=20 # maximum values for the stabiliser (in pixels) - 20 is a good start value
est_left=40 est_top=40 est_right=40 est_bottom=40 est_cont=1.4 #crop and contast values for special Estimate clip
stab_reference= o.crop(est_left,est_top,-est_right,-est_bottom).tweak(cont=est_cont).MT_binarize(threshold=80).greyscale().invert()
mdata=DePanEstimate(stab_reference,trust=1.0,dxmax=maxstabH,dymax=maxstabV)
DePanStabilize(o,data=mdata,cutoff=0.5,dxmax=maxstabH,dymax=maxstabV,method=0,mirror=15)#.deflicker()
This is probably the least effective. Does more of a slow vertical screen movement to try and minimize bounce. Tape head artifacts at the top of the tape go down about 3/4 of an inch on the screen when it does this. So the end result, instead of jerky bouncing, is more smooth bouncing.

DePanStabilize in AVISynth:
Code:
AssumeTFF()
QTGMC(Preset="slow")
mdata= DePanEstimate(trust=1.0,dxmax=4,dymax=20,range=1,pixaspect=1)
DePanStabilize(data=mdata,cutoff=0.2,dxmax=4,dymax=12,method=1,mirror=0,pixaspect=1)
This produces great results. Almost completely eliminates the flicker/bounce in the footage.

VirtualDub Deflicker:
No code here, this is the plugin for VirtualDub. Requires two separate passes to use. This plugin to me seems to do slightly less stabilization than DePanStabilize on really bad footage. With DePanStabilize footage that moves around a lot is rock solid, Deflicker still has some movement.

Further testing will be required this weekend to see if DePan or Deflicker are better than the other overall for my situation. My capture computer I'm testing this on can't seem to handle a StackHorizontal AVISynth script and either crashes in WMP or is jerky in VirtualDub so kind of defeats the ability to truly see a side by side. Mostly a slow hard drive issue from what I can see running two vids at once.

JR
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02-18-2015, 08:16 AM
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lordsmurf lordsmurf is offline
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Quote:
I have rarely, if at all, seen the point of a frame based TBC since putting the Panasonic ES15 in line with my video captures.
Then you're lucky. Because dropped frames still happen without the external TBC. The ES doesn't correct that.

Image bouncing (non-technical layman "jitter") is sometimes the side effect of a TBC. The not-really-TBC-but-still-TBC in the ES15 could cause this. Does it exist without that in the workflow? Not that I'm suggesting removing it, but simply to understand where the error originates.

stab() and my various stabmod() filters can often correct most/all it. But it really depends on the footage.

There are also methods of deinterlace + antialiasing that can correct this as well. But that's generally reserved for more serious issues.

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