HyperFrames Tutorial: Edit Videos With Codex in ChatGPT

1. Get the ChatGPT desktop app and open Codex

Download the ChatGPT desktop app for Mac or Windows and sign in. Since 9 July 2026, Codex is inside it on every plan, including Free. Switch from Chat to Codex, and start a new chat there.

Menu names can shift between app versions. If a label doesn't match, look for the closest one.

Why: the edit needs an agent that can work in a folder on your computer. The chat side of the app can't do that.

2. Set permissions before Codex touches your files

Check the permission menu in Codex before you give it any footage. Pick the option that asks for approval, and keep full access off. OpenAI's permissions docs describe a workspace profile that allows writes inside your project folder only, and a full-access profile that removes the sandbox and "should be used only when that broad access is intentional." Per the approvals docs, Codex asks before editing files outside the workspace or running commands that need the internet.

When it asks, read what it wants to run. Installing packages from npm needs the internet, so expect an approval request in step 4.

Why: your recordings and client footage live on this computer. The folder boundary keeps the agent inside the one project you chose. For more on setting limits, see AI agent guardrails.

3. Install Node.js 22 and FFmpeg (terminal step)

This is the only part that feels technical. You're installing 2 free programs: Node.js runs HyperFrames, and FFmpeg handles the audio and video. The HyperFrames README lists Node.js 22 or newer and FFmpeg as requirements. The starter in step 4 also uses Python 3 for its cutting script.

Node.js: download the LTS installer from nodejs.org and click through it like any app.

FFmpeg on a Mac: if you have Homebrew, run brew install ffmpeg. On Windows: run winget install ffmpeg, one of the options listed on gyan.dev.

Then paste the version checks below into the terminal in Codex, or ask Codex: "Check whether Node.js 22+, Python 3 and FFmpeg are installed, and tell me what's missing." Done when all 3 print a version number.

Why: if a tool is missing, every later step fails with a confusing error. Checking now saves you from debugging an edit that was never going to render.

node --version     # should say v22 or higher
python3 --version  # should say Python 3.something
ffmpeg -version    # should print a version, not "command not found"

4. Render a 6-second test before adding your footage

Get my free video-editing starter on GitHub. Use the green Code button and Download ZIP if you don't use git, then unzip it and open that folder in Codex. It includes a sample, a cutting script, a title preset, an editing brief and the workflow. Private footage, client media, soundboard files and credentials are left out.

Run the commands below from the starter folder, or ask Codex to run them. The sample is a 6-second silent title animation, so it needs no footage and no API key. The first install downloads the pieces it needs, and the first render may download a browser, so give it a few minutes.

Done when a new MP4 shows up in the renders folder and plays. If a command fails, paste the error into Codex and ask what's missing before moving on.

Why: a test with no footage proves your setup works. If something breaks later, you know it's the edit, not the install.

git clone https://github.com/drleadflow/aiceo-video-editing-starter.git
cd aiceo-video-editing-starter
npm install      # downloads HyperFrames and its helpers
npm run check    # checks the sample composition for errors
npm run render   # renders the 6-second sample into renders/

5. Keep one project folder per video

Inside the starter, create projects/my-reel and copy your recording in as source.mp4. Keep the untouched original somewhere safe too. Put any transcript in the same folder, B-roll and sound in an assets subfolder, and each revision in its own v01, v02 or v03 folder.

Why: the agent works from one folder instead of searching your whole computer, and a bad revision never overwrites a good one.

6. Write the direction before you ask for an edit

Fill in the template below and save it in your project folder as direction.md. This is the part the Reddit editors were right about: the agent can cut, but it can't decide what your video is for. One main point, one audience, and a short list of what must stay.

If you're unsure of the main point, work it out in a regular ChatGPT chat first, then paste the finished direction into Codex. For the prompt shape, see how to prompt like an operator.

Why: vague asks get generic edits. A written direction gives you something to judge the result against in step 12.

VIDEO: projects/my-reel/source.mp4
AUDIENCE: [who is watching, e.g. med spa owners]
MAIN POINT: [the one idea they should remember]
TARGET LENGTH: [e.g. 45 seconds, vertical]
MUST KEEP: [lines, pauses or repetition that are deliberate]
CUT: [mistakes, false starts, dead air, tangents]
HOOK: [the question or claim the video answers]
LOOK: two-line title, accent color on line one, white on line two, no big panel, face clear
B-ROLL I HAVE: [file names and what each one shows]
DON'T: invent speech, upload anything new that costs money, or overwrite earlier versions

7. Inspect the video and get word timings

Tell Codex to inspect your source file and report duration, orientation, frame rate, audio tracks, and whether the color metadata says HDR or SDR (ffprobe reports all of these). Then have it reuse your transcript or suggest a way to transcribe.

ElevenLabs speech to text is optional. If you use it, copy .env.example to .env and add your own key locally. The starter never calls a transcription service on its own. Done when you have checked word timings and no key was pasted into the chat.

Why: an iPhone HDR clip treated as normal video comes out washed out, and cuts are only as precise as the word timings behind them.

8. Make the clean cut first

Paste the edit prompt from Starter prompts below along with your direction. Ask for the clean talking-head cut before any effects. Review the sentences it wants to keep and protect any repetition you meant. Save the kept ranges in keep.json, then run the cutter once they make sense. It writes a time map next to the edited video.

Done when the cut is tight and means the same as your original. Listen at every join before moving on.

Why: if the talking head doesn't work on its own, no title or B-roll will save it.

python3 scripts/cut.py projects/my-reel/source.mp4 projects/my-reel/keep.json projects/my-reel/v01/cut.mp4

# keep.json uses ORIGINAL source seconds, for example:
# {"keep": [[0.2, 3.5], [5.1, 8.0]]}
# Replace these sample ranges with the reviewed ranges for your own video.

9. Make the hook readable

Tell Codex to apply presets/two-line-impact.json to a new composition for your cut. Ask for 3 short hook options and pick one the video answers. To choose between them, score the hooks before you post. Mine became STOP on line one and SELF-SABOTAGE on line two. Accent color on the first line, white on the second, both clear of your face.

Done when both lines read at phone size with no big rectangle covering you.

Why: most people watch on a phone. A title that looks premium on a laptop can be unreadable at phone size.

10. Swap decoration for B-roll that shows the point

Give the agent your local B-roll files and tell it which spoken idea each one should show. Have it log the source ranges it uses so no shot repeats by accident. For my accountability section we used partner exercise footage, then group curls later. Remove tiny stage labels and decorative rails.

Done when each visual explains the sentence being spoken. If it doesn't help, cut it.

Why: agents like adding graphics. Every extra element competes with your face and your point.

11. Give the sound a place to land

Start with one short opening effect in a gap in your speech. Ask for a gentle push-in to match, then watch the first few seconds. Say exactly what's wrong: the gap is too long, the effect cuts into a word, or the music is too loud. If a reaction beat gets inserted, have the agent shift every later track by the same amount. Use your own licensed assets.

Why: sound placed over a word makes you hard to understand, and one inserted beat can knock everything after it out of sync.

12. Review the file that will be posted

Ask Codex to run the HyperFrames check and render a new MP4. Open the export, not the editing preview. Watch it at normal speed and phone size, and listen to the cuts. Go through the review rules below, note each issue with a timestamp, then ask for a new version that fixes them. Give one concrete note at a time.

Done when you have a finished file, the editable project and a record of what was checked. A passing automated check doesn't prove the edit feels right.

Why: the export is what your audience sees. Previews can hide encoding problems, audio pops and color shifts.

REVIEW RULES (watch the exported MP4 at phone size)
[ ] Does the video make the MAIN POINT from direction.md?
[ ] Hook readable in the first seconds, clear of my face
[ ] Every cut: no clipped words, no audio pops
[ ] Captions in sync after the cuts
[ ] No important part of my face or hands cropped off
[ ] No repeated B-roll shot
[ ] No tiny unreadable labels
[ ] Color looks like the original, not washed out
[ ] Sound effects land in gaps, music under my voice
Each issue: timestamp + what's wrong + what I want instead