Turn a Long Video Into Shorts With AI: Step by Step

How do you turn a long video into shorts with AI?

You turn a long video into shorts with AI by giving an AI clip tool the video (a file or a link), letting it propose self-contained moments, and then editing each proposed clip into a vertical, captioned short with a strong opening. The AI does the slow part, which is watching and transcribing hours of footage; you do the part that decides whether a clip gets watched and stays on the right side of platform rules.

A short here means any vertical video for YouTube Shorts, TikTok or Instagram Reels. Repurposing means turning one piece of content into several formats for different places. This guide is the pillar of our repurposing series: if your long content is audio-first, read the companion guide on how to repurpose podcast content, and once you have a pile of clips, see how often to post on TikTok, Instagram and YouTube Shorts.

The full process has seven steps:

1. Pick the right source video.
2. Let AI find candidate moments.
3. Choose the moments that stand on their own.
4. Reframe to vertical.
5. Rewrite the first seconds as a hook.
6. Add captions people can read.
7. Check length, rights and originality, then post.

Which long videos make the best shorts?

The best source videos have people saying clear, complete things. Interviews, podcasts, live streams, webinars, talks and Q&A sessions work well because they contain many short moments that make sense without the rest. A tightly scripted tutorial, where step 4 only makes sense after step 3, usually gives fewer good clips.

Before you start, check three things:

• You own it or have the rights. Clipping your own videos is the safe case. Clipping other people's videos raises copyright and originality problems covered below.
• The audio is clean. Captions, transcripts and the AI's moment detection all depend on the speech being understandable.
• The speaker is visible. If the original is a wide shot with two people far apart, vertical reframing will be harder.

How does AI find the best moments in a long video?

Most AI clip makers start by transcribing the speech and analysing the video. They then look for passages that work as a unit: a question and its answer, a story with an ending, a strong opinion, a surprising number, a laugh. Each candidate becomes a clip with a start and end point you can adjust.

You can usually do this from a file upload or, with some tools, by pasting a link to a YouTube video or a Twitch stream. For example, BINAI's Clip a link tool takes a YouTube, Twitch or X link, finds the moments worth posting and cuts them into short vertical clips framed on whoever is speaking.

YouTube also has a built-in option for your own uploads. When it launched in July 2022, the Edit into a Short tool let creators turn part of one of their existing videos into a Short, and Shorts made this way link back to the original video. Only the original creator can do this with their video, which tells you how YouTube thinks about clipping: it is meant for your own content.

How do you choose which moments to keep?

AI suggestions are a starting list, not the final cut. Watch each candidate with the sound off and then with the sound on, and keep it only if it passes these tests:

• It makes sense alone. A viewer who never saw the long video understands what is going on within a few seconds.
• It has one idea. One tip, one story or one opinion per clip. Two ideas usually means two clips.
• It ends cleanly. The clip finishes on a payoff, not halfway through a sentence.
• It is accurate. A strong statement taken out of context can say something the speaker did not mean. Check names, numbers and claims before posting.
• It is not a near-copy of another clip. Ten clips that make the same point are one clip.

A useful habit is to write a one-line title for each clip before editing it. If you cannot write that line, the clip probably has no clear point.

How do you reframe a horizontal video to vertical?

Reframing means cropping a 16:9 horizontal video into a 9:16 vertical frame while keeping the important subject in view. A straight centre crop often cuts people out of the frame, so AI reframing tracks the face or the active speaker and moves the crop with them.

Things to check after the AI has reframed a clip:

• Speaker switches. In a two-person interview the frame should cut or pan to whoever is talking, not stay on the listener.
• On-screen text and slides. If the original has a slide or a chart, a tight crop may cut it in half. Use a split layout (speaker on top, slide below) or re-create the key text as a caption.
• Safe areas. Each app puts buttons, the username and the description over the bottom and right side of the video. Keep faces and captions away from those edges.

YouTube categorises square or vertical videos of up to three minutes as Shorts, and suggests a wider ratio such as 16:9 if you do not want a video treated as a Short. For TikTok and Reels, vertical is the norm.

How do you write a hook for a short made from a long video?

A hook is the first one to three seconds of a short, the part that has to give a scrolling viewer a reason to stay. Long videos rarely start their best moments with a hook, because in context the viewer was already watching.

Practical ways to add one without inventing anything:

• Start later. Cut the warm-up ("So, yeah, I think that...") and begin on the strongest sentence.
• Lead with the payoff. Show a second of the result or the punchline first, then the explanation.
• Add a text line. A short on-screen line that states the question the clip answers ("Why most first ads lose money").
• Make the first frame move. A static first frame looks like a paused video.

Do not write a hook that promises something the clip does not deliver. YouTube's spam policy prohibits misleading titles, thumbnails and descriptions that trick people into clicking, and a misleading hook works against you anyway, because viewers swipe away when the promise is not kept.

How should you add captions to shorts?

Captions matter twice on short video: many people scroll with the sound off, and the words on screen help viewers follow quick speech. Burned-in captions (part of the image) also stay visible when the clip is reposted elsewhere.

What makes captions readable:

• Short lines. A few words at a time, timed to the speech.
• Enough time on screen. If a caption flashes past before it can be read, it is decoration, not a caption.
• High contrast. White or yellow text with an outline or a background box.
• Correct words. Machine transcription gets names, brands and jargon wrong.

YouTube's own help page on automatic captions says they work on long-form videos and Shorts, but warns that quality varies with accents, background noise and overlapping speakers, and tells creators to always review and edit them. The same applies to any AI caption tool: read every line before you publish.

How long can shorts be on YouTube, TikTok and Instagram?

Length limits change, so treat this as a snapshot as of October 2026, taken from the platforms' own help pages or announcements.

Some third-party sites report longer recording options on Instagram for some accounts; we could not confirm that on an Instagram page, so we use the 3-minute recommendation limit above.

The Content ID rule is the one that catches people out. If your long video includes licensed music, TV footage or anyone else's material, a Short longer than a minute that picks up a claim will not play anywhere on YouTube. Either keep those clips under a minute, remove the claimed material, or clip parts that contain only your own audio and footage.

Is it allowed to make shorts from someone else's video?

This is where most clipping channels get into trouble. The platform rules are clear:

• YouTube. Its reused content policy, part of the YouTube Partner Program monetization policies, lists "clips of moments from your favorite show edited together with little or no narrative" and short videos compiled from other social sites as not allowed for monetization, and says the policy applies even if you have the original creator's permission. Critical reviews, reactions with your own commentary and edited footage where you add a storyline and commentary are listed as allowed. Read our full guide to the YouTube reused content policy.
• TikTok. Its Community Guidelines say content is ineligible for the For You feed if it includes unoriginal or reused material without anything new, giving clips that show someone else's watermark as an example.
• Instagram. Its creator guidance says Instagram avoids recommending reposted content, content with noticeable watermarks and accounts that regularly collect and reshare others' content.

If a streamer or podcaster gives you permission to clip their videos, that permission solves the copyright question, but on YouTube it does not solve the reused content question: you still need to add something of your own, such as commentary, context or a clear editorial angle.

What should you check before posting each clip?

Run this short checklist on every clip:

1. Rights: the clip contains only your material, licensed material, or material you have permission to use.
2. Originality: if any of it is not yours, you have added real commentary or editing, and there are no other platforms' watermarks.
3. Length: within the platform's limit, and under a minute on YouTube if any claimable music or footage is present.
4. Hook: something happens in the first seconds.
5. Captions: correct words, readable speed, away from the app's buttons.
6. Facts: names, numbers and claims are right, and the clip does not change the meaning of what was said.
7. Audio: not clipping, not too quiet compared with other videos in the feed.
8. Link back: on YouTube you can add a related video to a Short so viewers can jump to the full video; this needs advanced feature access, and the linked video must be public or unlisted.

BINAI's pre-post check looks for several of these automatically: material used without permission, a video too close to the original, wrong facts, captions too fast to read and sound that is too loud or too quiet, each with the second it happens. It lowers the risk; how far a clip travels is always up to the platform.

How many shorts should you post from one video?

There is no official number. Post the clips that are good on their own and spread them out instead of posting twenty near-identical clips in an hour. YouTube's Shorts product lead Todd Sherman has said that a batch of lower-quality videos with weak engagement is energy better spent making fewer, better videos. Our guide on how often to post on TikTok, Instagram and YouTube Shorts collects what each platform has actually said about frequency.

If you are a small business deciding where clips fit in your wider content plan, start with our hub on AI content creation for small business.

Make it with BINAI

Paste a YouTube, Twitch or X link into BINAI and Clip a link returns vertical clips framed on the speaker, with scrolling captions and an optional fact check. Every clip stays editable piece by piece, and the check flags problems before you post. See the plans to pick the one that fits how much you clip.

Sources

• Understand three-minute YouTube Shorts — YouTube Help
• YouTube channel monetization policies (reused and inauthentic content) — YouTube Help
• Spam, deceptive practices and scams policies — YouTube Help
• Use automatic captioning — YouTube Help
• Add a related video to your YouTube Shorts — YouTube Help
• YouTube now lets creators make Shorts from existing videos — 9to5Google
• Community Guidelines: For You feed eligibility and unoriginal content — TikTok
• TikTok video length guide for 2026 — Sociality.io
• Instagram officially expands Reels length to 3 minutes — Social Media Today
• Tips for improving your reach — Instagram for Creators
• YouTube shares advice for Shorts creators — Social Media Today