FFmpeg encod set of time stamped images as Iframes I have a set of images that are in time stamped order ( the unit is seconds ) but not in a set interval 

012.png
017.png
024.png


etc.

How can I encode them so that each image is an Iframe at that given interval ?

Also possibly this is not what I want to do . I'm not sure if its mandatory to have videos have their Iframes at a fixed interval ( forgive my naivety about the subject )

Hopefully the images would interpolate between each other smoothly ( with a feel of motion ) . I can imagine a way to do it by just creating my own in-between images by interpolating in some way between two frames ( no chance I do as good a job as encoders already do ). 

I feel like though that this is exactly what an encoder does and am trying to figure out if I can leverage it to do this frame generation work for me by handing it a list of Iframes with timestamps . 

If this is something that needs to be done at a lower level c++ or by working directly with an encoder ( if thats the right term ) I would certainly be willing to work on that level . I am really unsure of the approach to take . 

-------- Additional Information 

I took a look at

http://theora.org/doc/libtheora-1.0/group__encfuncs.html#gdbe7dd66b411c2d61ab8153c15308750
But there doesn't seem to be a way to insert a frame at a target position .
Your understanding of what an encoder does is incorrect. It doesn't make up images to fill in the time between I frames. It does somewhat the opposite: it takes a full series of complete images and decomposes them so that only the I frames and the differences between them remain.

What you're asking for is, in animation terms, called tweening. The linked article will point you to some software that can do automated inbetweening, but it's usually not useful for real-life images over the durations you seem to have. For smaller intervals (a frame or two) the process is called interpolation.