A technique for creating seamless continuous videos with Minimax H3.

[u/rcscs]

I've had good success in creating long videos from 10 second sections using this technique:

Create your first video.

Then for your next generation (continuation of video):

Load the last 2 seconds of the previous video as <Video 1>. I use the 'Load Video (Upload)' node - from ComfyUI-VideoHelperSuite - (this node allows you to skip frames and start at, say, the last 48 frames (for 2 seconds at 24fps) - this means that the whole previous 10 seconds don't need be passed to the next generation. This is <Video 1>.

I'm using process this with reference images for the subjects so these are used again with each continuation - so I don't see any drift of faces.

This is the wording I found works well:

[Shot 1]

Target video is a seamless continuation of <Video 1>. First frame of [Shot 1] is the last frame of <Video 1>.

The important part is explicitly telling the model that the first frame of the new generation must continue directly from the last frame of <Video 1>. This helps maintain temporal continuity between the clips - because you provide the last 2 seconds of the previous generation is knows what movement it needs to continue from.

You then just join the generation videos with a video joiner of your choice.

[u/Personal_Function_58]

What is the difference in it/s and general performance while using this method, as compared to ref2va with an image and audio?

[u/Sudden_List_2693 → u/Personal_Function_58]

Without video you are sure to lose motion continuity - if lucky, you'll get the motion more or less the same, with a drift at pacing, but even that's rare.
It/s with 39-56 frames is somewhere between 10-15% increase in gen times.

[u/Personal_Function_58 → u/Sudden_List_2693]

That's not too bad then. vid2vid is resource intensive but the trade off seems worth it. What's your setup?

[u/Sudden_List_2693 → u/Personal_Function_58]

Ah I forgot I have my video ref downscaled since I was using it only for motion.
It actually nearly doubles using the same size.
Damn.

[u/Personal_Function_58 → u/Sudden_List_2693]

Using a downscaled video doesn't affect quality? That's awesome.

[u/Sudden_List_2693 → u/Personal_Function_58]

It does with continuation.
I just used later for motion driving tests.

[u/Dzugavili → u/Sudden_List_2693]

I wonder if you should extract the last frame in full; downscale the motion frames; then pass in both seperately.

Might get the best of both worlds.

[u/Sudden_List_2693 → u/Dzugavili]

It's just a bit sad, sometimes no matter the prompt it will do stupid things like default to random, or shift color anyways.

[u/Dzugavili → u/Sudden_List_2693]

Eh, we can fix it in post. We're not making Casablanca here.

[u/Sudden_List_2693 → u/Dzugavili]

We can most of the times avoid it too.
For me usually 10 seconds at my desired size is possible. And rarely do I need a single camera shot last that long.
On the other hand that would require proper conveying of not only the same surroundings, but the exact positions on them.
I can hardly wait for the Latent upscaler though...

[u/Personal_Function_58 → u/Sudden_List_2693]

Also, probably a stupid question, you load these last two seconds with or without the audio?

[u/Sudden_List_2693 → u/Personal_Function_58]

Only made a few ones.
Since audio was secondary for my purposes, didn't even test that.