Black frames between clips

Hi. I am using kdenlive (in Linux) to generate a short movie (10 min) of an animated technical presentation which combines clips made with NodeBox, animated screen captures, voice, and background music. However, when looking at the output (both with rendering and when using the monitor) a black frame appears between every two adjacent transitions, which is very visible because they have a white background. I could get rid of that by slightly overlapping these two clips, but I'd prefer to avoid having to do that.

I know this is not a rendering problem actually, but I am not sure it is a bug in kdenlive, and the rendering section seemed to be the closest one.

I am using Ubuntu 10.10 and kdenlive 0.7.8 from the kdenlive repositories. The only slightly strange thing is that I am using FFmpeg version SVN-r25041 compiled from the project repositories (I needed the x264 profiles for another task). If anyone has any idea of what I could change / check / etc. I'd be most grateful.

Cheers (and thanks to the developers for this most wonderful tool!).

Forums:

in order to use transitions 2 clips HAVE to be overlapped by a tiny bit. that's to the best of my knowledge anyway. otherwise i am not sure what you're referring to. maybe you could show a zoomed screen grab of your kdenlive project.

Hi. Thanks for your message. Actually my message was not clear: when I wrote "adjacent transitions" I means "adjacent clips". See the effect at

http://link.ls.fi.upm.es/~mcarro/dp.mp4

between seconds 1 and 2. A black frame is clearly visible. However, I think I found the reason: the clips were generated at 20fps and the movie was rendered at 30 fps, so additional frames are needed. However it seems that when joining two clips a black frame was inserted, instead of interpolating (if needed) frames from the clips. Maybe a should file this as a bug?

Does the problem go away if you reduce the duration of the clips on the timeline by one frame?
I failed to reproduce this using a bright 15 fps screencast in both 29.97 fps and 25 fps projects. I suppose there could be a number of factors. Try to recreate using the simplest possible project. Then, maybe we can narrow down the source of the problem - a clip format?

I have black frames between clips and found a quick workaround: you have to cut last 4 (four) frames of every clip. This is a bit more convenient method than overlapping.

I have made minimal project:

http://pik-pik.ee/temp/kdenlive_blackframe.tar (33,6 MiB).

$ md5sum kdenlive_blackframe.tar
96e59f6f3fed8a4cd1f0515628fcd58f kdenlive_blackframe.tar

Black frame is between tiger and the city. Project folder is /home/valka/kdenlive.

Sony camcoder records video in MTS files:
Codec: H.264,
Size: 1920x1080,
FPS: 25,
Scanning: Progressive.

And I encode to:
Render profile: H.264,
Threads: 4,
Video bitrate: 4000,
Audio bitrate: 128,
Passes: 2-pass.

I use Archlinux. Package versions:
kdenlive 0.9.2-1
mlt 0.8.0-1
ffmpeg 1:0.11.1-1

Sorry for ressurecting the old post ^^"

Hi!

This is a common problem with MTS files. I have suggested to make a function in kdenlive to be able to cut of 4 frames (or how many frames you want) from multiple clips in the timeline. This way we can easily edit MTS clips, and also use this feature for other tasks that needs cutting of multiple clips at once.

See my post (had to put in a space in the URL due to the spam filter): http://kdenlive.org/forum/ change-multiple-clips-duration-and-move-clips-timeline-same-time/