Blackmagic Cintel Scanner User Manual  Deflicker

The Deflicker plugin handles such diverse issues as flickering exposure in timelapse clips, flickering fluorescent lighting, flickering in archival film sources, and in certain subtle cases even the ‘rolling bars’ found on video screens shot with cameras having mismatched shutter speeds. Two key aspects to this filter are that it only targets rapid, temporally unstable variations in lightness, and that it’s able to target only the areas of an image where flickering appears, leaving all other parts of the image untouched. As a result, this plugin can often repair problems once considered ‘unfixable.’

(Top) Original image with flicker, (Bottom) Result setting Deflicker to Fluoro Light, (clip courtesy Redline Films)

Main Parameters

By default, the top section of this plugin exposes a single control, which in many cases may be all you need.

• Deflicker Setting menu: The top two options, ‘timelapse’ and ‘fluoro light’, are presets that effectively eliminate two different categories of flickering artifacts. If neither of these presets is quite as effective as you’d hoped, a third option, ‘advanced controls’, opens up the ‘temporal NR’ controls at the heart of this plugin to let you tailor it further to your needs.

Temporal NR

Hidden by default, these controls only appear when you set ‘deflicker setting’ to ‘advanced controls’, and let you choose how to detect motion in the scene so that flickering may be correctly addressed relative to the motion of subjects and items within the frame where it appears.

• Frames Either Side: Specifies the number of frames to analyze to determine what’s in motion. Higher values are not always better; the best setting is, again, scene dependent. The default is 3.

• Mo.Est. Type: Picks the method DaVinci Resolve uses to analyze the image to detect motion. Despite the names of the available options, which options will work best is highly scene dependent. ‘Faster’ is less processor intensive, but less accurate, however this can be an advantage and actually do a better job with high detail images that would confuse the ‘better’ option. Choosing ‘better’ is more accurate, but more processor intensive, and ‘better’ will try harder to match fine details which can sometimes cause problems. None lets you disable motion analysis altogether, which can work well (and will be considerably faster) in situations where there’s no motion in the scene at all. The default is ‘better’.

• Motion Range: Three settings, ‘small’, ‘medium’, and ‘large’, let you choose the speed of the motion in the frame that should be detected.

• Luma threshold: Determines the threshold above which changes in luma will not be considered flicker. The range is 0–100, 0 deflickers nothing, 100 applies deflickering to everything. The default is 100.

• Chroma Threshold: Determines the threshold above which changes in chroma will not be considered flicker. The range is 0–100, 0 deflickers nothing, 100 applies deflickering to everything. The default is 100.

• Gang Luma Chroma: Lets you choose whether to gang the luma and chroma threshold sliders or not.

• Motion Threshold: Defines the threshold above which motion will not be considered flicker.

Speed Optimization Options

Closed by default, opening this control group reveals two controls:

• Reduced-Detail Motion checkbox: On by default, reduces the amount of detail that’s analyzed to detect flicker. In many cases, this setting makes no visible difference but increases processing speed. Disable this setting if your clip has fine detail that is being smoothed too aggressively.

• Limit Analysis Area checkbox: Turning this on reveals controls over a sample box that you can use to limit deflickering to a specific region of the image. This option is useful when (a) only one part of the image is flickering, so focusing on just that area speeds the operation considerably, or (b) part of the image is being smoothed too much by deflickering that’s fixing another part of the image very well.

Restore Original Detail After Deflicker

Closed by default, opening this control group reveals two controls:

• Detail to Restore slider: Lets you quickly isolate grain, fine detail, and sharp edges that should not be affected by the deflicker operation, preserving those fine details exactly.

• Show Detail Restored checkbox: Turning this checkbox on lets you see the edges that are detected and used by the ‘detail to restore’ slider, to help you tune this operation.

Output

The Output menu lets you choose what deflicker outputs, with options to help you troubleshoot problem clips. Here are the available options:

• Deflickered Result: The final, repaired result. This is the default setting.

• Detected Flicker: This option shows you a mask that highlights the parts of the image that are being detected as having flickering, to help you evaluate whether the correct parts of the image are being targeted. This mask can be very subtle, however.

• Magnified Flicker: This options shows you an exaggerated version of the detected flicker mask, to make it easier to see what the deflicker plugin is doing.