PrepCut v1.0.1

macOS Gatekeeper Note

PrepCut v1.0.1 is unsigned. After moving PrepCut.app to Applications, if macOS blocks it and you trust the copy you downloaded, run:

xattr -dr com.apple.quarantine /Applications/PrepCut.app

PrepCut fixes videos that won’t import into Final Cut Pro.

Drop a file → get a working .mov.

• No re-encoding unless needed
• Fast remux when possible
• Emergency mode for stubborn files

PrepCut is a minimal macOS desktop app for preparing video files for Final Cut Pro and Logic. It uses ffprobe to inspect each file, then uses ffmpeg to remux compatible files or convert only the streams required by the selected settings.

PrepCut always outputs .mov files. By default, outputs are written to:

~/Movies/PrepCut

License

PrepCut is open source under the GNU General Public License version 3 or later. See LICENSE.

PrepCut uses PyQt6 and calls FFmpeg/ffprobe for media processing. FFmpeg and PyQt6 are licensed separately; see THIRD_PARTY_LICENSES.md.

Requirements

• macOS on Apple Silicon
• Python 3.11 or newer for source runs

What It Does

• Drag video files into the window.
• PrepCut processes files one at a time.
• Supported video is copied without re-encoding.
• Supported audio is copied without re-encoding.
• Incompatible audio can be converted to AAC or PCM 16-bit.
• Unsupported video can fail, convert to ProRes LT, or convert to ProRes 422.
• Emergency Mode forces ProRes 422 video and PCM 16-bit audio.

Output filenames use this format:

original_name - PrepCut.mov

If the output already exists, PrepCut appends _1, _2, and so on.

Run From Source

python3 -m venv .venv
source .venv/bin/activate
python -m pip install -r requirements.txt
python main.py

FFmpeg For Development

FFmpeg and ffprobe are not included in this repository.

Release DMGs may bundle FFmpeg and ffprobe. FFmpeg is licensed separately. See THIRD_PARTY_LICENSES.md.

For local development, install FFmpeg with Homebrew:

brew install ffmpeg

The standard Homebrew FFmpeg build may include GPL options. That is allowed for PrepCut releases because PrepCut itself is GPL-licensed, but release maintainers must still provide the required source and license notices for the exact FFmpeg binaries they distribute.

PrepCut looks for ffmpeg and ffprobe in this order:

1. Inside a packaged PrepCut app bundle.
2. ./vendor/ffmpeg/ next to the source code.
3. The system PATH.

If PrepCut cannot find them, place executable binaries here:

./vendor/ffmpeg/ffmpeg
./vendor/ffmpeg/ffprobe

The repository keeps vendor/ffmpeg/.gitkeep, but does not include actual binaries.

Usage

1. Open PrepCut.
2. Drop video files into the window.
3. Files are written to ~/Movies/PrepCut unless you change the output folder.
4. Use Settings to choose audio conversion and unsupported video behavior.
5. Enable Emergency Mode only when you want full ProRes 422 + PCM conversion.

Emergency Mode increases file size because it re-encodes both video and audio.

Settings

Audio conversion for incompatible audio:

• AAC, using the source bitrate when available and above 192k.
• Lossless PCM 16-bit.

Unsupported video handling:

• Fail.
• Convert to ProRes LT.
• Convert to ProRes 422.

Emergency Mode:

• Converts any input to ProRes 422 video and PCM 16-bit audio.
• Overrides all other processing logic.

Settings persist across launches.

Packaging

Do not commit FFmpeg or ffprobe binaries to this repository.

Recommended public release FFmpeg build:

• FFmpeg 7.1.1 from https://ffmpeg.org/releases/
• configured without --enable-nonfree
• configured with VideoToolbox and AudioToolbox support

This is enough for PrepCut's remuxing, AAC/PCM audio conversion, and ProRes VideoToolbox output without bundling extra codec libraries that PrepCut does not need.

The build used for release binaries should be documented in LICENSES/FFMPEG_BUILD.md.

To prepare a release build, make sure ffmpeg and ffprobe are available on PATH, then run:

./build_mac.sh

The build script copies those binaries into:

./vendor/ffmpeg/ffmpeg
./vendor/ffmpeg/ffprobe

Then it uses PyInstaller and outputs:

dist/PrepCut.app
dist/PrepCut.dmg

The script refuses FFmpeg builds that report --enable-nonfree. GPL-enabled FFmpeg builds are allowed because PrepCut is GPL-licensed.

Before publishing a DMG, verify the license terms of the exact FFmpeg and ffprobe binaries bundled in the app.

DMG Notes

The build script creates a DMG containing:

• PrepCut.app
• README.md
• README.txt
• VERSION
• LICENSE
• THIRD_PARTY_LICENSES.md
• LICENSES/

Troubleshooting

If video codec is unsupported, enable a ProRes fallback in Settings or convert the file with HandBrake.

If ffmpeg is missing, place ffmpeg and ffprobe in ./vendor/ffmpeg/ or install FFmpeg so both tools are available on PATH.