Blending Video Tracks in KDEnlive | |  |
Before you can blend tracks together, you need to overlap them - and to do this, you need to have a free spot in the Timeline. Often, there will not be such an area - and you will need to create a new video track in which to place the clip. This is easily done in KDEnlive, by right-clicking on any of the icons (
) in an existing track. This will display a list of options - choose "Add Track":
A dialogue box will display; choose to insert a video track either before or after the current one and click "OK" to create it:
One of the most popular video effects is to overlay a title on a video track. Luckily, KDEnlive includes a built-in facility to create a title clip that can be overlaid with another video track by selecting:
Project → Add Title
A dialogue box will open up, allowing you to create a new video clip. Click on the Add Text icon (-or use the shortcut CTRL-T):
Note: you can also add an image here - that you may have already prepared in GIMP - instead of text
Click on the location where you want the text to appear and begin typing:
When the title looks good, click "OK" to create the clip - the dialogue box will close and the new clip will appear in the "Project Tree" (-with the name "Title"):
Drag the new clip to the video track above the clip that you want it to appear over in the Timeline; you should see the title now appearing in the video shown in the Project Monitor preview window (-as shown below):
If you click in the bottom part of the title track in the Timeline, you will see that a (Composite) Transition has been automatically applied to blend the tracks together:
Sometimes you just want to blend two tracks together - normally a foreground with a background. The easiest way to do this is with the "Blue Screen" option. Firstly, you need to place the foreground clip above the background clip in the Timeline:
Once the clip is in place, apply a Composite Transition to the topmost clip, by right clicking on the foreground clip and choosing:
Add Transition → Composite
Drag the Transition out to span the whole of the foreground clip:
Click on the foreground clip, then select the Effect List, expand the "alpha Manipulation" category and select the "Blue Screen" option:
Drag the "Blue Screen" option down to the foreground clip in the Timeline and release the mouse button to apply the effect:
Next, you need to select the chroma key colour to use when blending the two tracks together. This is normally best done by selecting the pipette tool and clicking on the desired colour inside the Project Monitor. In the example below, the colour we want to blend on is black:
Note: be careful that you set the Variance correctly: the variance value defines by how much a colour can vary from the selected colour and still be selected as the background area to be masked out. A value around 10 normally works well, but you should experiment with different values and observe which gives the best result
When all is well, you should see the background detail showing through in all areas that match the colour selected (-within the defined Variance set):
You can also view our video section for a video tutorial on using the Blue Screen function.