Turn long videos into scroll-stopping clips with ClipForge

Welcome: what ClipForge does for you

You've got a 40-minute podcast, a founder interview, or a pile of creator footage. Somewhere inside are five great 30-second clips. Finding them, cutting them cleanly, captioning them and making them platform-ready usually takes hours.

ClipForge does the slow parts for you. Claude reads the transcript and proposes the best moments, ClipForge cuts and captions them precisely, and you stay in charge of what gets published.

What you need

• A Windows 10/11 PC or a Mac, with about 3 GB of free space
• The ClipForge zip file from whoever shared it with you
• A Claude account (any plan). An API key is optional; Lesson 4 explains the difference.
• A talking video to practice with: a podcast, interview, tutorial or testimonial, ideally 5 to 30 minutes long with clear audio

How to use this course

• One lesson per screen. Use Next at the bottom, or jump around with the lesson list.
• Click Mark complete when you finish a lesson. The timeline at the top fills in, and your progress is saved in this browser.
• Click any screenshot to see it full size.
• Tracks 1 and 2 are the essentials. Track 3 is for ads, Track 4 for making it your own, and Track 5 is optional for technical folks.

How ClipForge thinks

Here's the one idea that makes everything else click: Claude can't watch video. It reads. So ClipForge turns your video into a transcript, lets Claude make the editorial calls on the words, and leaves every frame-level job to precise software.

Why it's built this way

When an AI tries to pick exact timestamps on its own, it gets them wrong: clips run long, and cuts land mid-word. In one published test, every single cut landed mid-sentence. ClipForge avoids this by having Claude point at words, then checking every pick before anything is rendered:

• Clips must start and end on full sentences.
• Fillers like "um" and "uh" and long pauses are cut automatically.
• Each clip's length is measured against your rules; clips that miss are sent back for fixing.

Who decides what

Install ClipForge Studio

On Windows

1. Unzip ClipForge somewhere short, like C:\ClipForge. Avoid your Desktop if it syncs to OneDrive (big videos plus cloud sync is slow), and avoid deeply nested folders: Windows has a path-length limit that can break the install.
2. Double-click Setup ClipForge.cmd. A window walks through four checks: Python, ffmpeg (the video engine), ClipForge's components, and an optional desktop shortcut. If Python or ffmpeg are missing it offers to install them; type Y and press Enter.
3. If Windows asks whether to run a downloaded file, choose Run (or More info → Run anyway). The script only changes the ClipForge folder, plus anything you agree to install.
4. Wait for "Setup complete." The first run takes a few minutes while components download.
5. Double-click Start ClipForge.cmd (or the new desktop shortcut). A black window opens, then your browser shows ClipForge Studio.

On a Mac

1. Install the two prerequisites with Homebrew:

2. Open Terminal in the ClipForge folder and run:

1. Double-click Start ClipForge.command to open the app.

If something goes wrong

First launch: connect Claude

Open Settings in the left sidebar. First, scroll to System check and make sure every line has a green tick. Each red line tells you how to fix it.

Choose how Claude plans your clips

Start with copy and paste if you're unsure. You can add a key any time.

If you want automatic planning

1. Go to console.anthropic.com, sign in, open API keys and create a key. Add some credit, and consider setting a monthly spend limit.
2. In ClipForge Settings, paste it into API key and click Save key. ClipForge tests it straight away.
3. Pick a Model: Opus 5.5 gives the best editorial judgment; Sonnet 5.5 costs half as much and is often enough for simple footage.

Two more settings

• Reviewer name: appears on every clip you approve.
• Transcription quality: "Balanced" is right for most computers. Choose "Fast" on older laptops.

Add your first video

In the Library, click New video. Drag a file into the box, or pick one already in your inbox folder.

Click Start. The video card shows progress while ClipForge reads the file and transcribes it. On a typical laptop that's somewhere between a few minutes and real time. The first run also downloads the speech model once.

Footage that clips well

• Clear audio beats pretty video. The transcript drives everything, so mumbled or music-heavy audio means weaker picks.
• Complete thoughts. Interviews and stories where people finish their points give Claude self-contained moments.
• Vertical or centered speakers need no reframing. Wide shots with the speaker off-center work too; you'll adjust framing in Lesson 9.

Brief Claude like an editor

The "What should Claude look for?" box is where you direct the edit. Claude already knows your recipe's rules (clip length, captions, quality bar), so use the brief for what's special about this video and this goal.

The brief formula

Starter briefs you can adapt

Plan clips and read the results

Open your video from the Library. If you chose Automatic, Claude is already planning; wait for the clips to appear. For copy and paste:

1. Click Copy prompt. It holds your recipe, the instructions and the transcript, but never the video.
2. Click Open Claude, start a new chat, paste and send.
3. Copy Claude's entire reply. It's fine if there's text around the code; ClipForge finds the plan inside.
4. Paste it into Paste Claude's reply and click Check plan.
5. If some clips need fixing, click Copy follow-up, paste it into the same Claude chat, and paste the new reply back.

Reading your plan

Trim and render

Trim by whole sentences

Click a clip, then use the buttons above the transcript:

• Start → Later sentence drops the first sentence. Great for cutting a slow lead-in so the hook hits sooner.
• End → Earlier sentence ends on a stronger line.
• The opposite buttons add a sentence back.

Trims always move by whole sentences, so you can't create a mid-word cut. If a trim would break a rule (say, the clip gets too short), ClipForge refuses it and tells you why. Nothing is lost.

Render

1. Tick the clips you want. New clips are ticked for you.
2. Optional: switch on Quick draft for a fast, low-quality preview when you're only checking content.
3. Click Render selected. Progress shows at the top of the page; you can keep reading other clips meanwhile.

Rendering is quick: on the test machine, 95 seconds of clips took about 14 seconds. Each clip is then checked automatically, and if you use an API key, Claude looks at its frames.

Review like an editor

Click Review on a rendered clip.

The 60-second review

1. Hook: watch only the first 3 seconds. Would you stop scrolling?
2. Standalone: would a stranger understand it with no context?
3. Payoff: does it end on an answer, a punchline or a lesson, not a setup?
4. Captions: scan for misspelled names. (Fix them next time with "Names and brands".)
5. Framing: is the face fully in frame and clear of the captions? Click the sampled frames to jump around.

The quality checks, in plain language

ClipForge runs 17 checks on every clip. You'll mostly see "All passed". Here's what to do when one doesn't:

Fix framing

If your source is wide (16:9), ClipForge crops a vertical window from the middle. When the speaker sits off to one side, drag the Framing slider toward them and click Apply and re-render. With an API key, Claude's frame check often suggests the right position; click to apply it.

Approve and export

At the bottom of the review page, fill in the approval form. ClipForge won't export until every field has an answer. That's deliberate: these are the details that cause takedowns and compliance problems after posting.

Click Approve and export. The clip appears on the Exports page, ready to upload.

Decode the file name

Each export has a matching .json file recording the source video, the recipe, the checks and your approval. If anyone ever asks "where did this clip come from and who signed it off?", the answer is right there.

Anatomy of a UGC ad

TikTok's own creative guidance says most of an ad's recall impact lands in the first seconds, and recommends a hook, body and close structure. ClipForge's ugc_ad_v1 recipe builds ads from five blocks:

Build ad variants from one shoot

Instead of cutting one ad, ClipForge has Claude find several hooks, bodies and CTAs in your footage, then renders every combination you ask for. Two hooks × two bodies × one CTA gives four ads, each with a label you can track.

Run a variant test

1. New video → choose the creator's footage → Recipe ugc_ad_v1.
2. Write a test brief, for example: "Audience: first-time small-business owners. Goal: trial sign-ups. 3 hooks (problem, surprising result, contrarian), 2 bodies, 1 CTA. Only use approved claims."
3. Plan, read the cards (each variant lists its blocks), render, review.
4. Approve the variants that pass. The variant label ends up in the file name, such as …_h2-b1-c1_…mp4.
5. Upload each variant with the same label in your ad manager's ad name. When results come in, you can see which hook won, not just which ad.

Claims and compliance

The approved claims list

The ad recipe points to a file called claims/approved_claims.yaml. It's a short list of facts your brand is allowed to say ("Free 14-day trial, no credit card"), with the evidence for each, plus things that are off-limits (guarantees, competitor comparisons, health outcomes). Claude may only use claims from this list, and flags anything else it hears.

Ask whoever owns the brand (or legal) to keep this file current. Open it from the Recipes page.

Before you approve an ad

Your house style: recipes

A recipe is your style guide, written down once and applied to every clip: length, caption look, loudness, how tight the cuts are, and what a reviewer must confirm. The Recipes page shows each one in plain language.

Common changes

How to edit safely

1. On the Recipes page, click Open file. It opens in your text editor.
2. Change the values. Keep the spacing at the start of each line; it matters.
3. Raise the version at the top, for example 1.0.0 → 1.1.0. Exports record the version, so you'll always know which style made which clip.
4. Save, then reload the Recipes page. If something's wrong, a red box tells you exactly which line.

Your weekly workflow, costs and fixes

A routine that scales

1. Batch your imports. Add the week's long videos in one go; they transcribe one after another while you do other things.
2. Brief and plan each video (5 minutes each).
3. Render everything that reads well in the transcript.
4. Review in one sitting with the 60-second routine. Use Previous/Next on the review page.
5. Upload from Exports and note which clips perform.

What it costs

The number that matters is cost per approved clip, including your review time. Keep an eye on how many rendered clips you actually approve; if it's low, sharpen your briefs before anything else.

Quick fixes

Under the hood (optional)

You can use ClipForge without ever reading this. If you're the technical person on your team, or just curious, here's how it fits together.

• ClipForge Studio is a small local web app. The black window runs a Python server on your computer, and the interface is a page in your browser at 127.0.0.1:8765. It only accepts connections from your own computer.
• Transcription uses Whisper (faster-whisper), running locally.
• The plan Claude writes is a short list of word ranges (an "edit decision list"). A checker validates it against the recipe before ffmpeg cuts anything.
• Rendering uses ffmpeg: cuts from the full-quality source, vertical crop, burned-in captions, and two-pass loudness normalization.
• Command line and Claude Code: the same pipeline runs as cf.py commands, and as a /edit-video skill for people who use Claude Code.

The builder's course

A separate 13-module technical course walks through building ClipForge from scratch: transcription, recipes, the checker, rendering, quality checks, the Claude Code skill, ad matrices, unattended batches and this app. It lives in the ClipForge project folder under course/, starting with 00-orientation.md. Ask whoever shared ClipForge with you for a copy.

Glossary

9:16

Vertical video, 1080 × 1920 pixels: the shape of TikTok, Reels and Shorts.

Recipe

Your saved house style: length, captions, sound, checks and approval fields.

Brief

What you tell Claude about this video: goal, audience, what to include, what to skip.

Plan

Claude's list of proposed clips, as ranges of words from the transcript.

Checker

ClipForge's rule check on every plan: full sentences, right length, no overlaps.

Hook

The first seconds of a clip, whose job is to stop the scroll.

Body / CTA

The middle of an ad (problem, demo, proof) and the closing call to action.

Variant

One combination of hook, body and CTA, labeled like h2-b1-c1.

Filler words

"Um", "uh" and similar sounds, removed automatically.

Draft render

A fast, low-quality render for checking content. It can't be approved.

Quality checks

17 automatic tests on every render: format, length, sync, loudness, captions, cuts.

LUFS

A loudness measurement. ClipForge targets −14 LUFS, a common social-video level.

Peak level

The loudest instant in the audio, kept below distortion.

Safe area

The part of the screen not covered by the app's buttons and captions.

Framing

Where the vertical window sits on a wide video, from left to right.

Frame check

Claude looking at a few stills from a render to spot cropping and caption problems.

Approved claims

The list of product facts an ad may say, owned by the brand.

API key

A secret code that lets ClipForge use Claude automatically, billed per use.

Model / Effort

Which Claude model plans (Opus for best judgment, Sonnet for lower cost) and how long it thinks.