Chromakeyer tutorial for Blender 2.91 VSE #b3d

well welcome to another three point edit tutorial and this time i'm going to be looking at doing a fast chroma keyer in the vse now this isn't that straightforward unfortunately it's not a one-click effect solution but it is it does render fairly quickly so if we go over here away from the threa the 3d view and the layout to video editing you may not have video editing as a option on these tabs you may have to click over here go down to video editing as a tab and choose video editing so we'll click on the tab and i've already added a clip with a bit of green screen background it's quite clean now the audio is irrelevant but you'll notice up here in the corner it's playing at 25 frames per second which is the speed of the video as it was recorded this will change as we add effects now i would ideally like to key out the green that is subtract the green and keep the person in the middle but i would also like the option of resizing my talent so that i can squeeze him down and move him around the frame now to do that i'll have to add a transform effect to this clip so we can select the clip by clicking on it let's add a strip or press shift a we need to go down to effects strip and add transform now on top is applied the transform effect nothing seems to happen i hit play we're still 20 frames per second it's not too bad but what's happening now is that our video is having its size changed even if it's only one 100 but we can resize it and we can rotate it like this and we can move it left and right up and down and we can distort it if we want to now you'll notice that we have excess background here and there's nothing showing underneath right so now we've taken care of moving our talent around on the screen we need to add another effect so i'm going to make sure the transform strip is selected then i'm going to add another effect strip i'm going to add a gaussian blur while that's selected i'm going to press the g key and the y key and drag it straight down underneath so it disappears underneath the original source video but this is where i'm going to build a key that is i'm going to make the image black and white where white is the green so i'm going to change the display or the preview window here so that we only see this bottom strip so if we look over here it's on track two so we need to go up to channel two now i'm looking at this clip hit play get 16 frames per second what i need to do is add a modifier so over here on our properties panel for the strip i'm going to add a hue correct modifier this is the hue correct window now we can see the green up here in our saturation but we want to change the value or brightness so what i'll do is grab that node or vertex and push it right up high and i'll grab this one and pull it down so what i'm saying here is everything that is green becomes very very white or maximum brightness and then we're going to pull down every other color so that we don't want to see that and you'll notice in the preview window up here that everything else has become black and the green has become white very close to it i can add another node and i can fill up that green space to improve the key or the parts that we want to remove that is the green now i'll go over to saturation s for saturation and i'm going to make the image black and white so pull everything down in fact what i'll do is select all of these other nodes with the shift key selected like this and press the x to delete them and then pull that down and you'll see this has all become black and white now this doesn't help us make the elements see through we're still what are we getting now about between 10 and 19 frames per second this doesn't make anything see-through so you can see the checkerboard is see-through but this element is not see-through so if we type back in here in our channel and our view settings zero that means the vse will look at all tracks from the top down now i've already got a background strip here so if i zoom out there it is i'm going to select that press g and drag it on top that seems a bit counter-intuitive doesn't it to put our background on top but what i'm going to do is cut a hole in this image from using this key channel we had down here and it will show through our transform clip so let's do that now i'm going to add a modifier and this one is a mask modifier i've selected strip and i'll tell it to give me the gaussian blur strip there we go goes in blur there it is so there is the hole that our gaussian blur strip cut and it's showing us the background image and our person but unfortunately has all of this space around it now how do we fill that in well we simply have to make a copy of our background so i'm going to press g and drag it straight up and i'm going to press shift d to duplicate that and pull it straight down so it was red because it was on top of the other clip and it can't live in the same place so we'll pop that underneath now we need to go over here and get rid of its copy of the mask we don't need that but it made everything go away so let's pop over to the strip property and we'll say it needs to be an alpha under so now this clip is underneath this clip we hit play and you can see we're getting about 5 to 10 frames per second we can change the performance by altering the resolution here if i drag down the percentage it should speed up and improve our rendering resolution speed so there we go back up to 15 frames or so at around 40 resolution so you go now if we zoom in you can see the quality is not great but if we wind that back up on a still frame to 100 we get to see what the quality of our key is now it's not perfect quality but it's certainly as good as some of the keys that i've seen on zoom calls if we go back to our modifiers on the gaussian blur press the value button we could probably change that in fact if we assess that track by typing in track channel 2 again we can see the edge here and we can try and improve that edge by modifying where our slope is for our brightness if i pull that slope across you can see it makes the edge a bit finer we want to eliminate the green go back to channel 0 to assess the entire image and now it's quite not quite so noisy if we want to improve that edge a little bit more because it looks a little bit sharp what we could do is go back up to the strip remember this is a gaussian blur effect i can select both of these by clicking and dragging over them and then sliding my cursor across to the right and it's softening up that edge now you may not see anything happen until i let go and change frame to the next frame so typically the vse requires a refresh all of the time every time you do something it doesn't refresh when you change of a value or a slider you actually have to reassess the frame so you can refresh the frame or step through to the next frame or do everything while you're in play mode so i can do that while it's playing it's always refreshing i can click and drag these values back and you can see that that blur becomes significantly smaller as i get further and further back something like four or five now the only problem with this effect is that i can't actually modify the spill this green edge here is called green spill i can't really attenuate that this is really just a very fast care that you can slap onto videos in real time i see there's a little bit of green spill down here as well just need to maximize our white value if it's a little bit gray you tend to see more green as you push the white point to maximum it gets rid of all that green spell from the green screen and then we can just simply use the transform effect to move the subject render as we like now it's not as reassessing the frame so i need to step forward one frame by using frame advance with the arrow key or i could use this button down here to frame advance there you go that's a quick vsc chroma key it's a little bit involved i guess but hopefully with the the transform effect rotation and scale will all get built into the master strip at some point in the future but the key takeaway is that we use the modifiers to choose the colors that we want to ma to remove so we make anything green pink white and everything else black then we remove the color using the saturation and then we apply that to our top strip our background strip to cut a hole in it you can see that there if i iso that clip you can see it has a hole cut in it and then we place the background in there which is just that 100 background there's our transform clip that's our original and this is our blurred version which is the key background you

Channel: David McSween

Views: 2,639

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Id: dI1kMT3O6uk

Length: 10min 47sec (647 seconds)

Published: Mon Jan 11 2021