DeScratch
The descratch video plugin can be used to remove vertical scratches
from film. It can also be used, after image rotation, to remove
horizontal noise lines that may appear on analog VHS
captures. For best results YUV should be the video format;
however if your format is RGB, it will first be converted
to YUV. There are many tuneable parameters necessary to get good
results for your specific film.
Figure 10.37 shows a list of the parameter descriptions:
Figure 10.37:
DeScratch control window
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Figure 10.38:
Various parameters of DeScratch
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- threshold
- instantaneous slope value; chroma difference in numerical pixels.
- asymmetry
- maximum asymmetry of surrounding
pixels.
- Mode
- None; Low=black; High=white; All=both;
y – processing mode for luma plane;
u– processing mode for chroma u plane;
v – processing mode for chroma v plane.
- width min/max
- minimal scratch width in pixels and maximum scratch width in pixels.
- len min/max
- percent minimal scratch length and percent maximum scratch length.
- len blur
- scaled radius of vertical blur for frame
analysis.
- len gap
- number of pixels for maximum vertical gap
to be closed.
- max angle
- maximal angle to vertical in degrees.
- fade
- percent of how much it fades to and how much it. Uses between before image and blurry image.
- border
- pixel thickness of border near scratch for partial restoration.
- Mark
- shows the potential scratch lines for ease of viewing and for debugging. It shows chosen pixels in the color green, close but still rejected in yellow, and extreme pixels in the color red. This makes it easy to vary some parameters to choose more or fewer scratch lines.
- Reset
- activating this button returns all of the parameters to their default values.
Figure 10.39 shows a before and after DeScratch scenario. With Mark set, you can see the black lines which indicate what the program was looking at to determine the scratches to remove.
Figure 10.39:
Original video with scratch; Option Mark selected and Final video
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The CINELERRA-GG Community, 2021
https://www.cinelerra-gg.org
