I have a simple animation of 3 seconds at 30fps for a total of 90 frames at 1280x720. I have inspected the files and they are correct. Rendering the animation with mencoder gives the correct animation:

$ mencoder "mf://*.png" -mf type=png:fps=30 -ovc lavc -o output.avi

When I add this into a kdenlive project with the profile "HD 720p 30 fps" as a slideshow, the last few frames of the animation are cut out. The new slideshow dialog shows all frames, selected from the pattern "frame.%04d.png", from frame.0000.png to frame.0089.png, and lists its length at 3 seconds. When I add it to the timeline, it shows as three seconds. Under "Clip Properties" it shows "Duration: 00:00:03:00" and "Frame Duration: 00:00:00:01" - exactly as it should. However, when I render it to any profile, it does not display the last few frames.

In a blank project, the video ends before the animation. In a project with a clip following the animation, it simply cuts to the next clip before the animation is finished. In both cases, it ends at the same point in the animation.

But the rendered video is still 3 seconds long. So I believe it is playing the slideshow at the wrong framerate; probably at 24fps instead of 30fps.

I have created all the projects again from scratch and can get nowhere with this. Any suggestions?

30 fps is actually 29.97 in reality, unless you have created a custom project template, what fps does the default 30 fps project actually say it is?

Since you already made an .avi with mencoder, why not import it as video?

@yellow - This is a prepackaged project template, but the Project Settings dialog lists the frame rate at "30/1" and mplayer says the rendered video is "30.000 fps".

@Marko - That wouldn't solve the issue I am having; it would just be a workaround. But this is actually a set of transparent PNGs intended to be composited with another clip.

You could maybe create a wideo with alpha using ffmpeg:

http://stackoverflow.com/questions/644684/turn-image-sequence-into-video-with-transparency

I had seen that SO post, but this would at most be a temporary solution as my company requires open standards and, as far as I am aware, Theora doesn't support transparency in videos.