MiniMax H3 (Hailuo) Video Upload Failed? Reference Video Specs Explained
MiniMax H3 accepts up to 3 reference videos, 2–15 seconds each and 15 seconds in total, MP4 or MOV, up to 50MB. It even takes 4K, so the size limit is usually what stops you. Here is how to prepare clips.
Why does MiniMax H3 reject my reference video?
MiniMax H3, the model behind Hailuo, can take reference videos together with images and audio to guide motion, camera work and style. Its input rules are more generous than most platforms in one way and stricter in another, and that is what catches people out.
The generous part is resolution: each side of the frame can be anywhere from 256 to 5760 pixels, so even 4K footage is allowed. The strict part is file size: 50MB per clip. In practice, a clip is far more likely to be refused for being too heavy than for being too large in resolution.
MiniMax H3 reference video limits
Up to 3 videos, each 2 to 15 seconds and 15 seconds combined, MP4 or MOV (H.264 or H.265), up to 50MB per clip, 23.976 to 60 FPS, each side 256–5760px, aspect ratio between 0.4 and 2.5.
4K is allowed, but 50MB is the real wall
Unlike Kling or Seedance, MiniMax H3 does not reject 4K by resolution. The problem is size. Phone 4K is usually recorded at 40–100 Mbps, which is 5 to 12MB for every second, so a 4K clip of just a few seconds can already pass 50MB. Because MiniMax H3 renders its own output at up to 2K (1440p on the short side), there is little to gain from sending 4K. Scaling to 1440p or 1080p keeps detail and lets a full 15-second reference fit comfortably under 50MB.
Film frame rates are fine, slow motion and timelapse are not
The accepted range starts at 23.976 FPS, so footage from a cinema camera or a 23.976 timeline can go in as it is. Anything above 60 FPS, such as 120 or 240 FPS slow motion, is refused, and so is anything below 23.976, such as timelapses or 15 FPS screen recordings. Converting those to 24 or 30 FPS first solves it. Since MiniMax H3 generates at 24 FPS, 24 is the best choice when you want to match frames later.
Three clips share one 15-second budget
You can add up to three reference videos, but together they must not exceed 15 seconds, and each one must be at least 2 seconds. Three 6-second clips (18 seconds) will be refused even though each is fine alone. Trim each clip to the moment that matters and keep the total at 15 seconds or less, for example 5 + 5 + 5 or 7 + 5 + 3. The output length is also set in whole seconds between 4 and 15, so whole-second inputs make planning easier.
Reference videos and first or last frame images do not mix
MiniMax H3 can start from a first frame image, end on a last frame image, or follow reference videos, but reference videos cannot be combined with first or last frame images in the same request. If you need both a fixed opening frame and motion from a reference clip, choose one approach per generation, or extract the frame you want as the first frame and describe the motion in the prompt instead.
Common reasons MiniMax H3 rejects a reference video
AI video encoders require strict video specifications in browser and cloud AI server environments. Upload errors typically occur due to the reasons below.
Preparing a reference video for MiniMax H3
Select MiniMax H3 in FixMyVideoForAI and drop in your clip. The tool checks length, file size, frame rate, resolution and codec against MiniMax H3's limits and shows exactly which items fail.
Converting re-encodes the clip to MP4 (H.264) at a constant frame rate, scales oversized footage down to 2K or below to bring the file under 50MB, and trims it to a whole number of seconds so you can plan your 15-second budget. Everything runs inside your browser, so your footage never leaves your computer.
Convert to Compliant Video Now (MiniMax H3 (Hailuo))
Safely convert in your browser to MP4 + H.264 + CFR without software installation.
Frequently Asked Questions
Yes, each side can be up to 5760px. But 4K files pass the 50MB limit very quickly, so scaling to 1440p or 1080p is usually needed anyway.