Sharpness Setting

We’re going full ITU-R with this standard! After all, the audio world has “Bleeding Eardrums” in the SPL scale. :rofl:

I just checked — yes, 50% is the default setting for the Sharpness filter amount and size, so no number to remember.

These videos were exported using XDCam, BTW. I used a polarizing filter on the camera which is why the sky is such a rich blue.

Below 50% is considered unsharpen, a form of blur.

For clarity, is below 50% an “unsharp mask” sharpening tool? Or does below 50% mean blur and above 50% means sharpen, with 50% being the zero processing point and we were basically looking at the original footage?

[quote=“Austin, post:25, topic:13984”]
50% being the zero processing point and we were basically looking at the original footage?[/quote]

If that is the case then there’s no point in using sharpen if we think 50% is best.

Here is 75% to bloody your eyeballs:

I’m having trouble seeing a difference between 50% and no sharpening (reduced gain).

66% gives it a touch more crispness which is what I was looking for. However, I am looking directly at Shotcut’s output without YouTube’s resampling. I’m looking at the “Accessible Route” sign on the right.

I need to correct myself. The frei0r plugin description says, "“Unsharp masking (port from Mplayer).” mplayer man page says it does gaussian blur or sharpen using unsharp mask.
The underlying plugin code range is [-1.5, 3.5] where 0 is the conversion point between blur and sharpen. 50% converts to 1.0, and the conversion point is actually 30%. A quick preview test confirms that.

Thanks for the clarification. Good to know.

I’m not sure where you get 30%.

-1.5 = 0%
3.5 = 100%
total range = 5

So 0 = 100% x (1.5 / 5) = 30%

I agree mostly with Austin. 50% is best, a remarkable improvement over the fuzzy 10% clip.
Why is your source-clip so fuzzy? Was the camera focus wrong?

30% is the cross-over point. Below 30% is blur, above 30% is sharpen. So the clip at 10% was actually being heavily blurred by the filter and looked worse than the original.

The camera was on auto-focus. It doesn’t look blurry here, but it doesn’t look particularly crisp, either.

You’re looking at it after YouTube resampling. Come to learn that 10% is heavy blur and 50% is no blur or sharpening. I’d have thought 0% would be no blur or sharpen but not so.

Thanks, now I got it!

So far, the amount of sharpen has been discussed in this topic.
But on my version of Shotcut there is also a setting for size in connection with the sharpness.
What does it actually do?

See Unsharp masking - Wikipedia

Size controls the amount of blur just like nearly all blur filters have as a parameter. Sharpening still creates a blur, but it uses this as a mask to sort of subtract from the original. This also explains why it can also be used to blur and why many tools call this function “unsharp” or “unsharp mask.” However, I do not like to call it that in Shotcut because it is confusing and deceptive for non-advanced users who are generally looking to increase sharpness (while also not limiting it to that).

I updated the help topic with this information:

In the -1.5 to +3.5 range, how much sharpening am I getting at Shotcut’s 60% setting?

(Available range) * (Percentage) + (Start value) = Parameter value
(3.5 - (-1.5)) * (0.60) + (-1.5) = +1.5

Substitute 30% instead of 60% into the formula above and the parameter value becomes zero, meaning the filter does nothing when set to 30%. That’s the cross-over point between blur and sharp.

There is another way to look at the sharpening value… In essence, the sharpness values are zero to +3.5 because the other direction is blur, so if 60% = +1.5, then the 60% setting is 1.5 / 3.5 = 43% of the way into the maximum sharpness that the filter can provide.

I don’t know how to make it any more confusing than that. :rofl:

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