sharpen video

joejon wrote on 1/21/2005, 5:16 PM
There is very little info. I can find on all the settings for sharpening the picture of video. If anyone has any resources or information, please let me know. I shot the video a little later in the day so it tends to be a little grainier than if shot in bright light. The following are my filter settings.
Track FX - Convolution Kernel, change in the middle matrix to 40.
Saturation - Amt. .15, Center .4, Spread .7, Low .2, High 0.
Broadcast Color - Lenient 7.5 setup.
Event FX - Unsharp Mask - Amt. .154, Radius .02, Threshold 0.
Contrast - .08
It's really hard to judge the settings because the changes look really good on my computer monitor, but the picture, when viewed on my TV seems to get even more grainy. Should I reset the Convolution Kernel to something else or change the Unsharp Mask filter? Maybe it's the Contrast? I have to render my video and burn it each time, I don't have a TV monitor hooked up to my computer, so this whole process of changing settings gets quite involved with a lot of time. Any info. is appreciated.

Comments

farss wrote on 1/21/2005, 5:46 PM
The median FX is very good for smoothing things out, expect long render times though. Any sharpening will make grain / noise worse, it sharpens the edge of the grain / noise making it more obvious.
Using median -> unsharpen mask can help.

Or if you have little or no motion in the shot motion blur can do wonders. Effectively what you are doing with that is integrating frames or if you like averaging the value of each pixel accross multiple frames. This is the basis of many noise cancelling techniques. I use MB a lot for all sorts of problems from old VHS tapes. Of course if your panning or zooming things can start to look very blurred (maybe you like that anyway) or if you've got the time you can mask out the moving bits.

Bob.
DGrob wrote on 1/21/2005, 7:53 PM
Duplicate your video track above. On the top track, add the convolution kernel and select the sharpen preset. Reduce top track opacity to 70% or so. Works pretty well for me.

Darryl
RichMacDonald wrote on 1/21/2005, 11:06 PM
>Duplicate your video track above. On the top track, add the convolution kernel and select the sharpen preset. Reduce top track opacity to 70% or so. Works pretty well for me.

Ditto. Alternatively, once you select the sharpen preset, play around with the middle value. Higher == less sharpening. This might be satisfactory just with a single track, i.e., no duplicate and opacity.

And do this instead of the unsharp mask. Don't ever use unsharp mask or sharpen. The convolution sharpen is superior.

if you're having noise issues, take a look at Mike Crash's smart smoother and dynamic noise reduction at crash site. They do a terrific job removing noise.
RichMacDonald wrote on 1/22/2005, 10:27 AM
>Broadcast Color - Lenient 7.5 setup

The problem with this setting is that it rudely crushes your whites. Roughly speaking, 0-100 is unchanged and anything above 100 is changed to 100. In an audio analogy, its a "brick wall limiter". I prefer to move all the smoothess sliders to 1.000. That way, if something goes above 100, then it reduces everythig above about 90 to make 100 max. So the adjustment is more gradual. More like a "compressor" in the audio world. This way you can still see variations in the near-white region.

I believe that moving *all* the sliders to 1.000 is poor understanding on my part, e.g., perhaps you only need to adjust the luma. Perhaps an expert will clarify.
joejon wrote on 1/23/2005, 12:33 PM
Thanks for all the suggestions. Here are some additional questions I now have.
1. It was stated that Broadcast Colors Lenient 7.5 was too limiting and to use the smoothness sliders. How do they affect the setting and picture? Please explain so I know what to set them at.
2. It was stated NOT to use the Unsharp Mask that the Convolusiton Kernel was much better. What is the Unsharp Mask used for then?
3. Convolution Kernel filter - so a setting of 20 has more sharpening than 40? Are there general guidlines to go by so I know what setting to try?
4. To sharpen the picture it was suggested to copy the video track and place it above. Then add the Convolution Kernel filter to the top track and put the Opacity at about 70%. Do I put all my other filters on just the top track or do I place them on both tracks? Here is a list of the ones I used:
Broadcast Colors - Lenient 7.5 setup
Saturation (slight increase)
Brightness/ Contrast
Median - light noise reduction
Switches - reduce interlace flicker
5. Median filter - the light setting or even .01 seems to take out quite a bit of the noise. Any guidelines to go by for this filter?
This is a lot of questions, so any you can help with is appreciated.
One last thing. Where can I get information on what the different filters are for and how to use them? Any books, web sites, informational videos?
BillyBoy wrote on 1/23/2005, 1:57 PM
One thing to keep in mind Joe is much of what you read here like in other forums regardless of topic is OPINION, usually based on personal experience and not necessarily fact.

Case in point sharpening an image. You can use the Convolusition Kernel and fool around with all kinds of matrix combinations and for SOME source files the results will exceed that possible using the so-called sharpen filters. Other times you're better off not.

My OPINION is turn off any and all clamps such as the Broadcast Colors feature. Its a legacy FX filter from earlier versions of Vegas. Now if you have version 4 or higher you're far better off checking if or not your project falls within "legal limits" using the build-in Scopes feature. Again, no one answer fits all. The only time you really need to worry about your signal being "legal" is if your poject is going to be broadcast over the air. A non legal signal (one that's too hot, meaning the highest whites are too bright) may cause noise on some TV's (older ones). If you're only make videos or DVD's you know never will be broadcast, then worrying about "legal" signals isn't that big a deal.

Try to avoid using the Median filter. It works, but it is VERY s l o w and if you use it for you're whole project and its of any size plan on the render taking DAYS, not hours. Just a pinch of Gussian blur works just well (remember my opinion), others may have their preferred method and again it depends on the source material, and how you'll render.

If you haven't visted yet check out mine:

www.bb-video.net




RichMacDonald wrote on 1/24/2005, 8:03 AM
>One thing to keep in mind Joe is much of what you read here like in other forums regardless of topic is OPINION, usually based on personal experience and not necessarily fact.

Always true.

>Case in point sharpening an image. You can use the Convolusition Kernel and fool around with all kinds of matrix combinations and for SOME source files the results will exceed that possible using the so-called sharpen filters. Other times you're better off not.

Perhaps true. But you have more controls with the convolution filter and that's always good, and I've always been able to improve over what the so-called sharpen filters can do. I consider the comparison to be a done deal. But obviously, ymmv.

>My OPINION is turn off any and all clamps such as the Broadcast Colors feature. [snip] A non legal signal (one that's too hot, meaning the highest whites are too bright) may cause noise on some TV's (older ones). If you're only make videos or DVD's you know never will be broadcast, then worrying about "legal" signals isn't that big a deal.

That's a really annoying noise, btw. A very loud buzz that drowns the rest of the audio. So if you're ever going to play your DVDs on some older TVs, then you do need to worry about "legal" signals. I can take my non legal clip, make a DVD, play it on my older POC TV, and verify that it is unlistenable. Good enough for me.
RichMacDonald wrote on 1/24/2005, 8:45 AM
>1. It was stated that Broadcast Colors Lenient 7.5 was too limiting and to use the smoothness sliders. How do they affect the setting and picture? Please explain so I know what to set them at.

The best answer is to look at the scope. Start with a hot signal without the broadcast colors filter. The scope will show you parts of the signal going above 100. Now add the broadcast colors lenient 7.5. You'll see all the values above 100 drop down to 100. Anything below 100 is unchanged. Now add smoothing. The values at 100 will be unaffected, but you'll now see adjustments in the 90 to 100 range.

Now look at the picture. Without the filter you'll have blazing white portions. With the filter and no smoothing, those blazing white portions become a bit grey, while the regions around those portions are unchanged. You may even see an "unnatural step change" between the altered portions and the rest of the clip. With smoothing, that step change disappears.

My suggestion to use smoothing was based on that "unnatural step change". I can usually see it and therefore I don't like it.

Important point: What you see on your monitor is not what you'll see on your TV. There can be a big difference between the two. You'll either need to link a TV to your editor, or create a DVD and watch it on your TV. I'll admit that I don't like the "clamped grey" look on my monitor, but that is irrelevant. What matters is how it looks on a TV.

>2. It was stated NOT to use the Unsharp Mask that the Convolusiton Kernel was much better. What is the Unsharp Mask used for then?

For me, nothing any more. It was what we used before we had the convolution filter. And the other sharpen filters were what we used before we had the unsharp mask.

>3. Convolution Kernel filter - so a setting of 20 has more sharpening than 40? Are there general guidlines to go by so I know what setting to try?

Yes, 20 is sharper than 40. As for general guidelines, not really. Reduce it to 8-15 and you'll see really funky stuff - not sharpening at all; rather edge enhancement. So stay away from there. 20 should be outside the funky range, but is still quite extreme usually. 40 is barely detectable.

General guidelines...hmm. My first thought is to suggest not using it at all :-) Sharpening is a painful rookie phase most people go through, imho. At least I did. Initially it looks really cool because there is suddenly all this detail you never saw in the original, so you crank it up. Then you start to focus on those ugly haloes around everything. Then your eye can see nothing but. Eventually you recoil every time you see a picture with obvious sharpening. The mind screams "ROOKIE!!" (I recently was sent a CD of wedding pictures. Excellent photography. Awful sharpening. I had to run the entire batch through a smoothing filter before I could even look at the pics. And I have some older pictures on my website that are embarrassing to me now :-)

As to your question, I'll generally use 25 for heavy sharpening and 35 for light sharpening. But any sharpening I do is going to be combined with another filter that does smoothing, because I don't like the resultant noise of sharpening. The idea is to enhance the edges only.

>4. To sharpen the picture it was suggested to copy the video track and place it above. Then add the Convolution Kernel filter to the top track and put the Opacity at about 70%. Do I put all my other filters on just the top track or do I place them on both tracks?

You'll have to try it and see, but in general you want your two tracks to be nearly identical, so I think you're probably faced with placing them on both tracks. Still, no way can anyone give a definitive answer without seeing the results for ourselves, so you'll have to trust your own eyes. Personally, I don't use the two-track + opacity approach, because while it does have additional controls it also has horrendous render times for minimal gain. Rather, I settle for one track and adjusting the center value of the convolution filter.

>5. Median filter - the light setting or even .01 seems to take out quite a bit of the noise. Any guidelines to go by for this filter?

Sorry, I really can't help you on this one. The median filter is known to be very slow, and people have complained that its lowest setting can still be too severe. I've never used it significantly. I do use Mike Crash's noise filters for my low light situations and think they're terrific.