Updated · 5 min read
4K AI video: when it is worth it and when 720p wins
4K is the most expensive button in the studio and the one most often pressed too early. Seedance 2.0 renders 3840 by 2160 with native audio, and the result is genuinely different for some uses and invisible for others. This is a short guide to telling them apart.
Where 4K shows
- Product and macro detail: fabric weave, print on a label, liquid texture.
- Anything that will be cropped or reframed later. A 4K master gives you room to punch in to 1080p without softness.
- Connected TV, YouTube and large screens, where 720p is visibly soft.
- Masters you will keep. Re-rendering later costs more than rendering once at the resolution you want.
Where 720p wins
- TikTok, Reels and Shorts. The platforms recompress heavily and most viewing is on a phone.
- Testing a prompt. Motion, pacing and prompt-following look the same at every resolution.
- Anything you will caption and stitch in a hurry.
What it costs
On Seedance 2.0, a 5-second clip is 25 credits at 720p and 59 at 1080p. A 15-second 4K clip is 366 credits. On the Basic plan that 4K clip is about $18, so render it once, at the end, after the prompt is proven at 720p.
Playback on phones
4K portrait video from the engine is encoded in a 10-bit format that many phone decoders refuse, which shows up as a black screen in a normal player. 2036 Studios renders a 1080p playback copy alongside every 4K master automatically. The library, the community feed and the watch pages play the copy; the download button gives you the master.
The workflow
- Write the prompt. Render at 720p on Seedance 2.0 Fast, 19 credits for 5 seconds.
- Fix what is wrong. Re-render on Fast until the motion and framing are right.
- Render the final once at 1080p or 4K on Seedance 2.0 with the same prompt and references.
- Cut and caption in Cinema Studio, which exports at the source resolution.
Questions, answered
Does Seedance 2.5 render 4K?+
No. Seedance 2.5 renders 480p and 720p. Seedance 2.0 renders up to 4K.
Can I upscale a finished 720p clip?+
An upscale tool exists and is in testing. For now, re-render at the resolution you need with the same prompt.
How long does a 4K render take?+
Longer than the studio keeps a page open, so it finishes in the background and appears in your library with a notification.