Hello.
I have a problem when trying to apply Mix Clips to videos. It simply doesn’t work, even though the track is active. It works correctly between videos and images, but not between videos.
I posted a video on YouTube demonstrating the problem:
" Kdenlive: Mix Clips doesn’t work on videos [HELP!] "
If anyone can help me, I would be extremely grateful!
Thanks in advance for your help!
Do you have enough frames on both sides?
Yes, I usually use videos that are longer than the ones in the video, and even then Mix Clips doesn’t work between them.
Which OS and version of Kdenlive? Installed or standalone?
Mixes need at least 5 frames at the end of the clip on the left and at the start of the clip on the right. You need to cut or trim the edges of both clips for this to work.
Thank you!!!
Now I saw the problem, I was actually trying to merge the videos in their original length, after trimming the edges of the videos it was possible to merge them.
OS: Windows 10
Kdenlive version: Installed & Standalone (I tried both)
One note: It would be nice to be able to merge the videos in their original length as well.
Anyway, thank you very much, now I can understand the situation.
I hope this topic can help other people who may have the same issue.
Glad I could help and clarify things. Please mark this thread as solved by selecting the answer/post with the solution.
And how is Kdenlive (or any video editor for that matter) supposed to do that? It needs frames on both sides of the mix to do the mixing (cross-fade, for example). So, if you just string together clips without trimming or cutting, Kdenlive would need to take five frames from each clip, moving everything that is to the right of the mix to the left, potentially breaking aligned clips further down the timeline. Keep in mind, there may be clips on tracks above or below the track where the mix is being added. How should Kdenlive deal with that? And what if there is no space on other tracks to move things around?
IMHO, this is better left to the editor which clips to mix and how and for how long. It needs a conscious decision, right?
Oh, cool, sorry for my ignorance on this. It was nice to learn a little more about how the software works through this little mule kick in the face.
Thanks again, the topic has been marked as solved.
Everyone started as a beginner 
No worries, and my apologies if I came across a bit harsh. Just trying to explain a bit about the inner workings so that ppl understand why something is not possible …
BTW, welcome to the forum and community. Nice to have you here.
No problem, man.
Thank you very much for helping me with my difficulty and contributing to my learning with Kdenlive and video editing softwares.
I really appreciate it!