Reducing Noise in Apple Final Cut Pro
Nov 16, 2010 12:00 PM, By Jan Ozer
First, you can choose a filter preset, like one from the list shown in Figure 5. You could also eschew the presets, and adjust noise reduction and sharpening values in the Filter Settings tab (which replaces the Device Noise Profile on the right of the interface when you click the Noise Filter Setting button on the top middle of the interface). Read the manual carefully if you decide to fly solo, however, since there's a lot of guidance like not to exceed 60 percent filtering in the Luminance channel because it "may lead to loss of fine details and unnaturally looking (over-smooth, plastic-like) results." Sounds just like the first round of results I got before reading the manual.
There's also an advanced filter control set, shown in Figure 6 (and there's the Noise Filter Settings button on top that opens the filter control area). This enables a high degree of customization, particularly since you can preview your results in four different channels. I particularly liked the granularity of the Sharpening controls, which let me sharpen just the Y values (luminance) and adjust settings for High, Mid, and Low noise levels.
Once you're done tinkering, click Apply to apply the settings and return to Final Cut Pro.
All the adjustments applied to this point are intraframe, applied individually to each frame. Back in the Filter tab, you select temporal filter settings, which affect multiple frames in sequence.
Briefly, the Temporal filter radius determines the number of frames used for temporal filtration, with 1 (for some reason), meaning that three frames are analyzed. You can increase the number of frames, which increases quality, but also increases processing time. I encoded at the default setting and at 5, and I determined that the extra wait was definitely worth it, as you'll see below.
The filter threshold determines what the filter "sees" as noise as opposed to true motion. At high values, the filter sees more of the frame-to-frame changes as noise, which it attempts to filter out, which can eliminate true motion from the video. At lower values, it sees more of the interframe changes as true motion, which it then leaves alone, which can increase the noise in the clip. I used the default setting in all my tests.
Adaptive filtration tells the filter to adapt to changing conditions in the clip, which seemed like a good idea, while Mix allows you to mix the filtered frames in with the original footage. I was concerned that the totally filtered clip would look unrealistic, so I tried a value of 80 for Mix.
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