I'm using Kdenlive Version 0.9.10
Using KDE Development Platform 4.8.5 (4.8.5)
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I have a basic question / issue with kdenlive. Basically I need to use animated elements in my videos ( in this example I'm using a numeric counter, but there are many things that I need to use that kdenlive can't create on it's own ).

Scenario #1: I create the counter in Blender and export it as a common video format. I want the counter to appear in the top right corner of my video. Here is where the problem begins! My video is 1280x720. If I create a lower resolution animated video element, it gets scaled up and appears much larger when I import it into my kdenlive project. It is also centered which I can't use. If I could scale the animated video element down and place it off center it would work. However, If I scale / offset that video layer, kdenlive crashes EVERY time repeatably.


So.. I try scenario #2
I use blender to create an animated video element that is the SAME resolution as the video that I'm inserting it into and position it in the right place when I create it in Blender. The problem is that to the best of my knowledge you can't create a video with a transparent background, so when I try to composite the two video layers together, the animated video element completely covers up my original video


How the heck do I solve this?! Using animated video elements in a video is a very simple, common and important task... surely someone has found a way to make this work?!

hakachukai wrote:I'm using a numeric counter, but there are many things that I need to use that kdenlive can't create on it's own

Kdenlive can do numeric counters see https://userbase.kde.org/Kdenlive/Manua ... namic_Text

If you want a transparent background in video the feature you are looking for is alpha channel. You want to create video with an alpha channel.

Your blender video might have already created such. But you might not be seeing this in kdenlive because you may not have added a transition between your blender animation and the track underneath. Add an composite transition between your two tracks with you animation in video track 1 and your main video on video track2. And see how that goes.

It might not work. I know it works with alpha channel data created by kdenlive using effects like blue screen and rotoscope. But I dunno how well it does with alpha data saved in a source video.

See https://userbase.kde.org/Kdenlive/Manua ... nipulation

https://userbase.kde.org/Kdenlive/Manua ... /Composite

Ok, so I got one method to work so far:

If you create your animation in Blender with a green background, you can use standard green screen techniques to overlay your animation video track over top of other video tracks. It can be messy though. Even though it did work for me, I had a slight green glow around my animation.

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Method #2:

You can have Blender render your animation to PNG frames using RGBA color. PNG supports transparency.
In kdenlive you then use Project --> Add Slide Show Clip --> and import the PNG sequence.
Set each PNG to be 1 frame in length.
Now you can overly your PNG sequence effect track over your other video tracks using and Affine transition and transparency will be preserved.

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However I can get this to work due to some type of bug that I can't figure out. I know that it works for many people, I just can't get it to work! Here are 3 screen shots that shows exactly what happens:

Step1: http://www.pasteall.org/pic/82234
Step 2: http://www.pasteall.org/pic/82235
Step 3: http://www.pasteall.org/pic/82236

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I tried some basic debugging using Strace at the time that the error happened. I didn't see anything that looked helpful or meaningful
Just a mega ton of automated Polling and clock events.

ok, I found the bug and figure out how to avoid triggering it. I'm now able to import a PNG image sequence with transparency.

Kdenlive has a file name bug in it.
When I had PNG file names like "counter.png0000.png" the bug was triggered and the Slideshow Import would fail.

When I have file names like "counter0000.png", it works without triggering the file name bug.

These strange file names were created because I manually entered ".png" in the file name box in Blender, while Blender was also appending a frame # and '.png' on the end of the file name I had entered in the box.

hakachukai wrote:Ok, so I got one method to work so far:
Even though it did work for me, I had a slight green glow around my animation.

This sounds like a problem with "Keyspill". This is where the light from the green background spills on to your subject and makes the chroma keying hard.

There is an effect in kdenlive that is supposed to able to correct for this https://userbase.kde.org/Kdenlive/Manua ... plillm0pup. It is a pretty complex effect though.

I wonder if what you are seeing is due to the way blender is lighting your scene. It might be throwing green light onto your animation subject in order to realistically render it. If you could turn that off in blender you might get more success. It would be perverse if you had one bit of software create a keyspill and then have to try and remove it using another bit of software.