# How to Make Long AI Videos Without Stitching 8-Second Clips

By Steven Van · 2026-09-28

Synthesys says its agent turns one brief into a 10 to 30 minute video, with a storyboard and credit cost shown before anything renders.

Synthesys has published a guide to making AI videos of 10 to 30 minutes from a single brief, without joining short clips in an editor. The post argues that most [Synthesys](<https://creatorstoolbox.com/tools/synthesys>) alternatives stop at 4 to 15 seconds per generation, so a 30-minute video means 120 to 225 clips before voiceover, captions, music and editing. The details are in the [vendor's guide](<https://synthesys.io/blog/how-to-make-long-ai-videos/>).

## The clip arithmetic

Using each tool's published limits, checked on 28 September 2026, the guide counts clips for 1,800 seconds of video:

- Google Veo 3.1 at 8 seconds: 225 clips. With Extend, each chain tops out at 148 seconds, so 13 separate chains.

- OpenAI Sora 2 at 12 seconds: 150 clips.

- Runway Gen-4 at 10 seconds: 180 clips.

- Higgsfield at 15 seconds per shot: 120 shots.

## The workflow

The Synthesys agent takes one brief and builds the video in these steps:

- Pick a format and length. Videos run from about 10 seconds to 30 minutes, in 9:16, 16:9 or 1:1.

- Describe the video in one sentence.

- Review the script and storyboard the agent writes. For long videos, the guide suggests checking chapter order first, then the lines.

- Check the credit cost shown on the approve button. Nothing renders until approval. Scripts, storyboards, voiceover, music and chatting with the agent are free.

- The agent voices the video, generates footage, adds captions and music, and assembles the cut.

- Edit by chat: reorder scenes, rewrite a line, change the voice or music, or ask for another language.

## What Synthesys saw in its own test

On 28 September 2026, the team ran a 10-minute faceless YouTube explainer on compound interest in the Faceless Story format, with default settings. The storyboard came back in about two minutes as 62 scenes and a planned length of 832 seconds (13 min 52 s), roughly 39% over the request. One chat message asking for 90 seconds produced a 29-scene, 120-second plan in under 50 seconds, about a third over. Neither plan was rendered.

The team then rendered a 60-second version. The storyboard had 12 scenes. The estimate under the prompt box said about 60 credits, but the approval card asked for 120, and that is what was charged. A wrong figure in scene 10 was corrected through chat in under a minute at no cost, since nothing had rendered. The finished 1:01 video (1080×1920, with narration, captions and music) was in the editor 6:32 after the brief. The team says the voice was right, while the captions and some of the footage were not.

[View media](<https://synthesys.io/blog/how-to-make-long-ai-videos/compound-interest-faceless-video.mp4>)

Video from the announcement showing how to make a long AI video from one brief

![Synthesys](<https://www.google.com/s2/favicons?domain=synthesys.io&sz=128>)

Synthesys

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[View Synthesys →](<https://creatorstoolbox.com/tools/synthesys>)

Sources

[Original source](<https://synthesys.io/blog/how-to-make-long-ai-videos/>)

[Read How to Make Long AI Videos Without Stitching 8-Second Clips on Creators Toolbox](<https://creatorstoolbox.com/blog/synthesys-how-to-make-long-ai-videos-without-stitching-8-second-clips>)

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Canonical source: https://creatorstoolbox.com/blog/synthesys-how-to-make-long-ai-videos-without-stitching-8-second-clips