Hello,
I'm very new to kdenlive and I have (maybe very stupid) question:
I have 720p 120fps video
What is the best way to do slowmotion video 720p 30fps?
Can I just load my video to the project as 30fps video or I should use Motion-speed effect?
Please let me know.

Thanks!

Cool! Noone knows

I found the interesting feature:
It is possible to import video as is (120fps) and then force to change the fps to 30 in clip properties.
But unfortunately length doesn't change. So if I had 10 sec in 120 fps and then changed it to 30fps I got 10sec of 30fps and lost 75% of the clip. Looks like it is not the best solution.

I found this on a seach for "slowmotion": viewtopic.php?f=265&t=114366

capslock wrote:I found this on a seach for "slowmotion": viewtopic.php?f=265&t=114366

Thank you for the reply. I saw that topic but there is no answer in it also.
The question is:
What is the best way to make 720p 30fps slow motion video from 720p 120fps source?
Use speed effect or some other trick?

Well I am currently facing the same challenge with 50fps to 25fps. My idea is this: Import footage into an <original framerate> project. Then render to png frames. Import the frames as a png sequence into a <destination framerate> project. The result should be a fine slowmotion which uses only the original footage.

Tried this today and it worked perfectly nice.

1. Extract png full frames from source using ffmpeg
ffmpeg -i 50fpsClip.MTS -r 50 -s 1920x1080 -f image2 slowmo-%03d.png

2. Import images into kdenlive project. Choose diashow with 1 frame time to show per image.
Feel free to cut unneeded leading and trailing images while importing by choosing only a subset of the images from step 1.

Use diashow as normal clip. With this handling the slowmo is super soft, but you cannot apply an addition slowmotion effect from kdenlive. In that case, use ffmpeg create a lossless clip in the destination framerate from the single images.

The PNG intermediate step is not necessarily required. There's a simple yet useful blog post about changing the framerate with ffmpeg. http://evorster.blogspot.de/2012/10/httpblog.html

There are also container modification programs that allow to change the framerate by modifying the meta data and without the need to pipe through the video stream.

That one is great - thank you!