How to turn long videos into YouTube Shorts with AI

TL;DR

• An AI video clipping agent reads a long video, finds moments that stand on their own, ranks them and returns vertical, captioned clips ready for YouTube Shorts.
• YouTube treats square or vertical videos up to 3 minutes as Shorts, and blocks any Short over 1 minute that carries an active copyright claim.
• The workflow runs in nine steps, from uploading the long video to linking each published Short back to it.
• Shorts earn through the YouTube Partner Program: 1,000 subscribers and 10 million qualified Shorts views in 90 days makes a channel eligible to apply, and monetizing creators keep 45% of their allocated revenue.
• Course platforms and other video platforms can clip their own library for Shorts marketing, route viewers back to their product and play the same clips in-app with a playback ID.

A 45-minute podcast episode, a recorded lecture or a three-hour live stream holds several moments that work on their own as Shorts. Pulling them out by hand means scrubbing the timeline, cutting, reframing 16:9 to 9:16, timing captions, writing a title and uploading, once per clip. YouTube's Edit into a Short tool helps, but it takes up to 60 seconds from one video at a time.

An AI video clipping agent turns that editing job into a review job: add the long video, describe a good moment, and choose from a ranked list of finished clips.

How AI video clipping agents are changing YouTube Shorts marketing

YouTube Shorts averages 200 billion daily views, and more than 1 million channels used YouTube's AI creation tools daily in December 2025, according to YouTube CEO Neal Mohan's 2026 letter. Shorts put a long-form library in front of people who scroll instead of search, and AI tools are part of how creators keep up with the posting pace.

Podcasters pull guest answers from full episodes, and educators cut single-idea explainers out of hour-long lectures. For a streamer, one full Twitch broadcast turns into a run of highlight Shorts. Marketing teams run the same play on product demos and event talks, so one launch webinar can fill a month of posts.

The FastPix AI video clipping agent handles the whole long-to-short job in one project workspace:

• Ranked moments. Every clip gets an engagement score out of 100, with detection tuned by genre. The score blends five signals: Contextual, Hook, Action, Intensity and Narrative (CHAIN). [VERIFY: marketing page only]
• Captions in short-form presets, applied to every clip as it generates.
• AI editor for trimming clips, moving and arranging them, adding transitions, cutting filler words and fixing audio, without exporting to another tool. [VERIFY: beta, not in the agent docs]
• B-roll dropped in so a talking-head moment has something to cut to. [VERIFY: beta, not in the agent docs]
• Vertical framing at 9:16 by default, with subject-aware reframing that keeps the speaker in shot. [VERIFY: reframing is beta]
• Publishing with AI-drafted titles and descriptions, published or scheduled to YouTube, Instagram, Facebook, LinkedIn and X, and tracked on one calendar.

Manual Shorts editing vs an AI video clipping agent

The manual column repeats for every clip. The agent column runs once per source video, leaving people to choose, polish and approve. A 60-minute source comes back as ranked clips in about 4 minutes. [VERIFY: marketing page only]

YouTube Shorts rules to know before you clip

• Length and shape. YouTube classifies square or vertical videos up to 3 minutes as Shorts for uploads on or after October 15, 2024. The agent's 3 to 5 minute clip option produces regular videos instead.
• Copyright claims. A Short over 1 minute with an active copyright claim is blocked globally and can't be monetized, and music or licensed footage in the long video carries into its clips.
• Ownership. Clip footage you own or have rights to. Continuing past the agent's upload step confirms the content is yours.
• Links. URLs in Shorts descriptions and comments aren't clickable. The related video feature (Step 9) is how a Short points to a longer video.
• Source quality. YouTube Studio downloads your own videos only at 720p or 360p, so the original export gives the agent a sharper source.

How to turn a long video into YouTube Shorts with an AI video clipping agent

These steps follow the FastPix AI video clipping agent, found under AI Agents in the FastPix dashboard and available on the Starter plan or higher. The AI video clipping agent docs cover every setting.

Step 1: Upload or import the long video

Create a project, then drag in a video or audio file, or paste a link from Google Drive, Twitch, Instagram, Facebook or X. Pasting a YouTube link is temporarily unavailable because of YouTube's download policy changes, so upload the original file directly or paste a Google Drive link to it. The source lands in your FastPix media library with its own media ID.

Step 2: Trim the source to the part worth clipping

Set a start and end time, or drag the waveform handles, to skip the intro, sponsor reads and dead air. Minutes consumed updates as you trim, and usage is based on the length you select.

Step 3: Set the genre, clip length and moments to find

Turn on Enable Clipping, then tune the output:

• Genre: pick one such as Podcasts, Educational / Webinar, Comedy, Gaming, News or Sports, or leave it on Auto.
• Clip length: for Shorts, pick Auto (up to 3 minutes), under 30 seconds, 30 to 59 seconds, 60 to 89 seconds, or 90 seconds to 3 minutes.
• Specific moments: a plain-language prompt such as "audience questions and the answers."
• Audio language: match the spoken language so captions transcribe correctly, or leave it on Auto.

Step 4: Choose a caption style

Pick a caption preset such as Reels Bold Yellow, Beast Pop, Karaoke or Indic Bold, or reuse a saved style from My Templates so every clip from the channel looks the same. Brand templates add a watermark, font and intro card automatically. [VERIFY: marketing page only] Then select Generate clips and follow progress on the project card in My Projects.

Step 5: Review clips ranked by engagement score

When the project shows Ready, each clip lists an engagement score out of 100, its duration and an AI-written title. Sort by score, then open a clip to read its AI summary and transcript, confirm the aspect ratio is 9:16, and use Download HD or Export XML if you want to finish the cut in your own editor. Projects expire after 7 days unless Auto-save is on.

Step 6: Refine clips in the AI editor

Select Edit Clip to open the AI editor and shape each cut before it goes out:

• Trim the start and end of a clip so it opens on the hook and ends on the payoff.
• Move and arrange clips and segments into the order that tells the story, for example opening on the guest's strongest line before the question that set it up.
• Add transitions between cuts so a Short built from two moments plays as one piece.
• Clean up filler words, uneven audio and caption text, working from the transcript.

Step 7: Add B-roll with AI

A clip of one person talking for 50 seconds gives viewers a single image to watch. B-roll in the AI editor drops supporting footage in while the speaker keeps talking, so a line about a product, a place or an idea shows it on screen.

Step 8: Publish or schedule to YouTube as Shorts

Connect your YouTube channel under Connect account, select the clips and choose Publish:

1. Pick the YouTube channel, plus Instagram, Facebook, LinkedIn or X if the clip belongs there too.
2. Use AI Copy Prompt to draft the title and description, then edit them.
3. Choose Publish now, or Schedule for later with a date and time.

Posts appear on the Calendar as Published or Scheduled, and only clips you approve go out. Spreading one video's clips across two weeks keeps a channel posting without a new recording; turn on Auto-save first so the project stays available for the whole schedule.

Step 9: Link each Short to the full video

In YouTube Studio, open the Short under Content, add a related video from your channel, and save. The link sits below your channel handle in the Shorts player and sends viewers to the full episode, lecture or stream. It needs advanced feature access and works with public or unlisted videos.

How Shorts from long videos earn money on YouTube

Shorts pay through the YouTube Partner Program. A channel can apply once it has 1,000 subscribers plus either 4,000 qualified watch hours in 12 months or 10 million qualified Shorts views in 90 days, and YouTube reviews every channel that applies. Back-catalog clips build toward the Shorts route, and viewers who follow a related video link to a public long-form video add qualified watch hours.

After joining, a channel accepts the Shorts Monetization Module to share in Shorts ad revenue, which is pooled and allocated by each channel's share of engaged views. Monetizing creators keep 45% of their allocated revenue, with or without music. Engaged views on non-original content don't count, which is one more reason to clip your own videos. Since August 24, 2026, YouTube counts a view the moment any video starts playing, while earnings still run on engaged views and eligibility on qualified views.

AI video clipping for course platforms and other video platforms

Course platforms, creator platforms, webinar tools and media apps already own a library of long videos. Clipped into Shorts, that library reaches people who have never visited, brings some of them back to the full content where the platform earns, and adds YouTube revenue once the platform's channel is in the Partner Program.

Bring Shorts viewers back to your own platform

Links in Shorts descriptions and comments aren't clickable, so the route back runs through the parts of YouTube that are:

1. The Short's related video points to a long-form preview on your channel, such as a free first lesson.
2. That long-form preview's description carries the clickable link to your platform (external links need advanced features).
3. Channel profile links, up to 14, catch viewers who tap through to your channel.

Name where the full lesson lives in the last seconds of the clip, since a URL in a Short's description can't be tapped.

Play the same clips inside your platform with a playback ID

A clip made through the FastPix clipping API is its own on-demand asset with a playback ID, and clips from the AI video clipping agent come back with playback IDs too. [VERIFY: docs confirm API clips; agent clips per marketing page] The stream URL https://stream.fastpix.com/{PLAYBACK_ID}.m3u8 plays in the FastPix Player or any HLS player. The moment that runs as a Short on YouTube can also play as a course preview on a landing page, a highlights row in your app or a short-form feed, with your player and none of YouTube's recommendations beside it.

Automate clipping through the API when your platform runs on FastPix

A platform already built on FastPix video infrastructure adds clipping without a second vendor, a re-upload or another contract, because the library is already there.

• Fixed-timestamp clips. When chapters, transcript search or an editor already marks the moment, send the source media ID with start and end times. The clip comes back as a new asset with its own playback ID, and video.media.ready fires when it's playable.
• AI clips on every upload. Trigger the AI video clipping agent when an upload finishes and receive ranked clips, each with a score and playback ID, on a webhook. [VERIFY: marketing page only; docs cover the dashboard workflow]
• Per-creator branding. Apply one brand template per creator so every clip carries that creator's watermark and font. [VERIFY: marketing page only]
• Live highlights. Clip a moment from a live stream while the broadcast is still running.

curl -X POST 'https://api.fastpix.com/v1/on-demand' \
  --user '{ACCESS_TOKEN_ID}:{SECRET_KEY}' \
  -H 'Content-Type: application/json' \
  -d '{
    "inputs": [
      { "type": "video", "url": "fp_mediaId://{MEDIA_ID}", "startTime": 754, "endTime": 812 }
    ],
    "accessPolicy": "public"
  }'

FastPix cuts on the nearest keyframe, so clip boundaries can shift by a few hundred milliseconds. Video clipping using API covers keyframes and more clipping use cases.

More ways video platforms use AI video clipping

Conclusion

A long video already contains its Shorts. An AI video clipping agent finds, ranks, captions, cleans up and schedules them, so nobody edits clip by clip. Creators get a back catalog that doubles as a posting calendar and a route to Shorts revenue. Course platforms and other video platforms get clips that market the product on YouTube and play inside it by playback ID, on the stack they already run.

The quickest test is a video you already have. The AI video clipping agent runs on the Starter plan, $10 a month with $25 of usage credits included each month, on top of a free FastPix account, and the first ranked list shows how many Shorts were sitting in that library.