Frame interpolation invents frames between the ones you have. Given a 24fps clip it can produce 60fps or a convincing slow motion, and when it works it looks like it was shot that way. When it fails it produces a specific, recognisable smear.
Scope: 8frame does not interpolate frames. There is no interpolation or slow-motion tool on the canvas. Interpolation is a desktop or local job. What the canvas can do is generate the slow shot directly, which is usually better and is the point of this page.
TL;DR
- Free options are mostly open-source tools you run locally; hosted free tiers are limited because the compute is heavy
- Where it breaks: occlusion, fast rotation, motion blur, and anything entering or leaving frame
- The better route: prompt for slow motion in the generation. It costs the same as any other clip
- Interpolation is for footage you already have and cannot reshoot
- A real high-frame-rate camera still beats both, including the phone in your pocket
How interpolation fails
It estimates motion between two frames and draws what should be in between. That estimate breaks predictably:
Occlusion. When something passes behind something else, the tool has to invent the part that was hidden. It guesses, and the guess warps.
Fast rotation. A spinning wheel or a turning head rotates further than the algorithm assumes, so it interpolates the short way round and the object appears to wobble.
Existing motion blur. A blurred arm has no defined edge to track. The interpolated frames smear further.
Entering and leaving frame. There is no previous frame for something that just arrived, so edges tear.
Very fast action. The more the subject moves between frames, the less information there is to work from. This is the ceiling: interpolating 24fps footage of something genuinely fast will not look shot at 120fps.
What works well: modest, continuous, unoccluded movement. A slow camera push, a gentle subject motion, a drifting plate. Which is, conveniently, exactly what b-roll is.
The better route: generate it slow
For generated video this is not a close call. Prompting for slow motion produces a coherent slow shot rather than an inferred one, and it costs no more than any other clip.
Canon 8frame prices, a credit is $0.01 at pack rate:
| Route | Clip | Credits |
|---|---|---|
| Wan 3.0 at 480p | 5s | 24 |
| Wan 3.0 Prime, any resolution | 5s | 34 |
| Wan 3.0 Prime, long take | 30s | 203 |
| Kling v3 Standard | 5s silent | 57 |
| Seedance 2.5 at 720p | 5s | 157 |
What to put in the prompt: "slow motion, high frame rate, 120fps look" plus the physical cue that makes it read, which is usually a substance. Falling water, dust in air, fabric settling, powder, smoke. Slow motion is legible because something small moves visibly, and naming that thing is what makes the shot work.
Seedance 2.5 at 157 credits is worth the premium specifically here, because slow motion is a physics shot and physical behaviour is what that model buys you. Water and cloth in slow motion are exactly where a cheaper model gets it wrong.
The long-take option: Wan 3.0 generates up to 30 seconds in one pass, and Prime is 203 credits for 30 seconds. A long, slow, continuous shot is one generation rather than an interpolation project.
When interpolation is genuinely right
Footage you already shot and cannot reshoot. The real use case.
Archival material. Old film at low frame rates, where any smoothing is an improvement.
Matching frame rates. Conforming 24fps material into a 60fps timeline.
For these, run an open-source tool locally (free, needs a GPU and setup) or use a desktop product's free tier for a one-off. We have not benchmarked them against each other and will not pretend to have.
The thing worth saying about 60fps
Interpolating cinematic 24fps footage to 60fps for its own sake usually makes it look worse, not better. The 24fps look is a large part of what reads as "filmed," and smoothing it produces the soap-opera effect that viewers dislike without being able to name.
Interpolate for slow motion, where the frames genuinely get used. For playback frame rate, leave 24fps alone.
FAQ
Does 8frame do slow motion or interpolation? No interpolation tool. Prompt for slow motion in the generation instead, which works better.
What is the best free interpolation tool? An open-source one running locally, if you have the hardware. Hosted free tiers are limited.
Can I make any clip slow motion? Technically. Convincingly only if the motion is modest and unoccluded.
Which model is best for generated slow motion? Seedance 2.5 at 157 credits, because slow motion is a physics shot.
Generate it slow rather than slowing it down. The 8frame canvas is free and unlimited, and generation is paid from $19/month.