A simple tool I vibecoded over a few weeks to interpolate gifs and webp animated images while still keeping the inbetween frame delay consistent.
Gifs and webp dont' all have a stable framerate, each frame has specific delay. Some frames are held for a little longer to make an effect. The classic interpolation nodes in comfyui don't take these delay into account and just give the same delay to every frame, wich can break the "rythm" of an animation.
The main feature of these custom nodes is that the delay is taken into account and redistributed to the frames accordingly (depending of the settings you chose).
It can also deduplicate the base gif. Sometime instead of one frame being held for longer, the same frame is shown multiple times. It deletes these frames and automatically add their delay to one frame.
It uses the RIFE or FILM models (from my testing RIFE is better 90% of the time)
(A simple working workflow is available within the nodes files)
Other notable features :
Setting for looping gifs to make the loop seamless (interpolate the last and first frames)
Automatically choose the best interpolation rate for you gif (to make it as close to the max fps a gif can support)
Lossless settings in the save node to make the results as sharp as the base input. (uses FFmpeg, be sure to have it installed on you system it if you want lossless results.)
Can automatically deduct the delay from the base frames to redistribute it to the new interpolated ones
You can drag'n drop files to the load node but you can also choose a file for bulk interpolation (the manually loaded gif will be ignored if a file is selected)
The save node can choose a save location, input the base filename, and append a chosen suffix + an interpolation multiplication suffix (for example 1234.gif can become 1234_interpolated_x4.gif) It really helps when comparing the before/after.
Easy Gif to webp conversion (or the opposite)
WARNINGS ! Things to keep in mind
Gifs/webp have a maximum of 50fps, going higher makes it play slower.
Animated images with more than 25fps cannot be interpolated without making the gif a bit slower.
Animated image converted from videos often have 30+ fps so they make poor candidates
For high res gifs with high interpolation rate, RAM consumption can be too high and make a OOM error.
Have fun :)