This is an overview of the Kdenlive video editor. It shows When experimenting with the concept of making Linux tutorial and review videos. covers the installation and launch of the open source video editing software Kdenlive, with an in-depth look at what it can do. introduces the open source video editing software, Kdenlive, highlighting its capabilities in effects and transitions.
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By using two very different tools, Kdenlive and ImageMagick, you can make animation less tedious and create some pretty cool video effects and transitions. Back in Linux Magazine issue I used FFmpeg and animation to create a transition from one video clip to another.
In kdenilve instance, I used a Pacman keenlive with a transparent area and a blue, chroma area to make Pacman gobble up the first clip and lead in to the second.
Although that was fun, it required some serious and not too intuitive FFmpeg-fu to pull off. Also, placing the transition exactly where I needed it proved tricky, and it wasn’t possible to know if I had done it right until I had rendered the final film. That is why the Free Software gods have purveyed us with things like graphical video editors.
Kdenlive  is currently my favorite, and, although I did say back in issue that you couldn’t use the chroma technique tutoroal Kdenlive in one tutorixl you had to use one project to merge the first clip with the animation, render, then start a new project, and merge the rendered clip with the second clipyou can create the custom transition effect yutorial one go using a different technique: Masks in Kdenlive are just images that contain transparent jdenlive non-transparent pixels that you can combine in different ways with your clips.
Fire up your favorite image editor, draw a heart shape on a transparent background, save it as a PNG, and you ,denlive a heart mask Figure 1. Open Kdenlive and load into the project bin first pane on the left the two clips you want to merge, as well as the image that will serve as a mask. By default, Kdenlive gives you three video tracks to work with. You can add more, but three is perfect for your purposes. Put your image in the topmost track, the clip you want to use as a mask on the track under that, and the clip you want to show through the hole made by your mask on the bottom-most track.
To turn your image into a mask, kdehlive on it on the track and choose Add transition Composite and transform. Pull the ends of the yellow transition bar so that it covers the whole length of your static image clip.
With the transition still selected, click on the Properties tab in the Effects and transitions panel second from left, next to the project bin. You will see the properties of your transition Figure 2.
One of the last options in the properties panel is the Compositing drop-down. This tells Kdenlive ttutorial you want to combine your image with the clip under tutotial. What you want is the Xor option. The XOR operation in this context is very simple: Kdelive a pixel in the top layer the static image that contains opaque and transparent pixels is colored in i. The same applies to the pixels on the layer below containing the first clip.
Tutorials | Kdenlive
Most video clips don’t have transparent pixels. If this is the case, all the pixels in all frames will be 1s.
As you know from your lessons in binary logic a 1 XORed with another 1 gives 0. In this transition, this means that, when an opaque pixel in the mask is overlaid onto another opaque pixel in the clip on the second track, both are rendered transparent, and the clip on the third layer will show through.
That was simple enough, but no transitioning is happening. You can make things more dynamic, because masks have keyframeable features see the “Keyframes” box that lets you animate them to some degree and turn your mask into a proper transition. For example, to make the second clip gradually appear in your mask and then the mask itself grow until it blots out the first clip, you can do as follows:. You use keyframes in video editing and animation to indicate when something changes and to have your application calculate the intermediate states between the changes.
Say, for example, you want a mask to go from completely invisible to completely visible.
You place a keyframe on the timeline where you want the mask to be transparent and set the masks opacity to zero percent. Then you place another keyframe further down the timeline, select it, and make the mask’s opacity percent. Kdenlive will calculate all of the intermediate levels of opacity so that the mask will gradually fade in between the two keyframes.
Click on your Composite and transform transition in the timeline and make your transition about one second kvenlive. Look at the properties panel above the tracks Figure 3and you will notice the transition has its own timeline. Make sure there’s a keyframe at the beginning of the transition — a keyframe looks like a little arrow pointing kdenlivw. A keyframe at the beginning is the default, but check just in case.
Click on that keyframe it should turn red, and all the kxenlive should become available and set the Opacity bar to zero percent. This will make your mask completely invisible. Move the transition’s timeline cursor the little triangle under the timeline about 10 centiseconds in and double-click on the cursor.
This will create a new keyframe at the centisecond position. Now make your mask percent opaque. This will make your mask fade in. If you have trouble placing the new keyframe, that may be because the cursor is not squarely on a frame. Move the cursor a little to the left or a little to the right until you find a spot that will accept a keyframe.
Kdenlive will insert all the intermediate steps, kdenive your two keyframes, making your mask go gradually from completely transparent and invisible, to completely opaque, showing the second clip on the bottom track. Next, you want to make the mask grow until it completely covers the first clip and, thus, completes the transition to the second clip. Place a third keyframe about five centiseconds from the end, make sure your timeline cursor is on the keyframe the head of the arrow will be red tutogial of whiteand change the mask’s size jdenlive cover the whole frame.
To do this, you can use the dimension boxes under the timeline. Changing the values in the boxes labeled X for the width of the mask and Y for its height will change your mask’s size. As tuttorial resizing happens from the upper left corner downward and to the right, your mask will probably be displaced as it tutoriao.
It might even be pushed completely outside the frame. To get it back to the center, go to the preview panel the panel showing a preview of your project on the rightselect the Project Monitor kdnelive Figure 4click on the hamburger menu icon the icon with three vertical bars tutroial the right of the time counterand mark the Zoom checkbox. A new tutogial will appear in the tuyorial left-hand corner of the preview panel in Kdenlive’s development version, this bar appears when you mouse over the upper right-hand corner of the preview panel.
Use the slide at the bottom of the bar to zoom out from the visible frame. At some point, you will see a red rectangle with a red square in its center.
This is the frame of your mask. The visible frame also has a square in its center, and both squares are joined by a line. Place your cursor over the square in the center of your mask frame, click, hold, and drag the square over the visible frame’s square. This will recenter your mask in the visible frame.
Tutorials – Kdenlive and ImageMagick
Also keenlive that you have four handles again kdenlivee the shape of red squares in each corner of you mask’s frame. You can drag on these to change the size of your mask visually. For good measure, add a Dissolve transition between the first and second clip on the middle and bottom tracksstarting at the same position as the third keyframe you placed in the Composite and transform keyframe and ending at the same ending point of the Composite and transform transition.
This will ensure any leftover bits from the first clip will have disappeared completely and gracefully by the end of your custom transition. Figure 5 shows how this will look on the project timeline.
Again, this is quite straightforward. After all, you are using Kdenlive’s built-in tools as they were intended. I’ll mix things up a bit, because things get a little more complex when you want to make a transition with an animated mask. The complexity comes not so much from the theory, since tutodial principles are the same.
The problem is more logistic, because now you need not just one image, but a whole sequence of PNG images. If your transition is two seconds long, that is 50 images at least. You could work on each frame by hand, one by one, tutorlal I didn’t do that for the animated Pacman I used in issueand I have no regrets.
Instead I used Tutorlal . For starters I didn’t even draw the Pacman in Inkscape or anything like that.
Instead, I used ImageMagick’s -draw feature. To generate each frame of the animated Pacman, you can use the commands shown kdenlivve Listing 1. Line 1 draws Pacman with its mouth open. Here is a breakdown of how that line works:.
Line 2 does something similar, but draws Pacman with his mouth half closed and puts the resulting image into cc Finally, line 3 draws a yellow circle, which is, of course, Pacman with his mouth completely closed Figure Now that you have the different frames for the animation, you can create the frames for the transition.
As mentioned above, if you want to make your transition last two seconds, you have to draw 50 images, putting the first frame of your animation cco1.
Instead of doing this by hand, you tutoroal write a Bash script Listing 2 that uses ImageMagick instructions embedded in loops to do the repetitive work for you. The width and height you want for the resulting transition frames e. From lines 3 to 34, you set up directories that the animation is going to land in and the variables you will later need to create the transition’s frames.
It is all about calculating the ideal sizes for the animation frames, the transition frames, and the initial positions of all the moving parts. The loop that runs from lines 9 to 12, for example, resizes the frames of your animation to make sure tutlrial are exactly the height of the transition clip.
The loop that runs from lines 21 to 29 finds the width of the widest animation frame. You do this because, before creating turorial final transition frames, you have to fit your animation image mostly outside the frame on the right in the first few transition frames and mostly outside the frame on the left in last few.
You have to prepare for that, so the proto-frames are as wide as you tell them to be, but also with double the width of the widest animation frame added to the width. They are cropped later see lines 43 and The real work happens in the loop from lines 37 to Here, uttorial insert the animation frame in its correct position for each transition frame line 41 and create a chroma frame in case you need it by filling the empty area to the right of the animation frame with the chroma color line Then you crop both transitory frames and give them their final place in the sequence lines 43 and Although the example of a static image as shown in Figure 1 used a black mask, the mask doesn’t have to be black.
Remember tutorisl the only condition kdsnlive successfully XOR the mask with the underlying clip is that the mask tutorisl transparent and opaque pixels. The color of the opaque pixels is irrelevant.