FFmpeg for Mac: install it for OneMacTools in one click
FFmpeg is the free, open-source engine behind OneMacTools’ video and audio tools. It isn’t bundled with the app, so the first time you open a tool that needs it, OneMacTools offers to install it through Homebrew with one click. You can also use a copy you already have. Image, PDF, file and on-device AI tools never need FFmpeg.
On this page
- What is FFmpeg, and why does OneMacTools use it?
- Which OneMacTools tools need FFmpeg?
- How to install FFmpeg on Mac from OneMacTools
- Using FFmpeg you already have (Homebrew, MacPorts or your own build)
- Formats and codecs FFmpeg unlocks
- Other helpers: yt-dlp, WebP tools and Ghostscript
- Updating FFmpeg
- FFmpeg not working? Fixes for common problems
- Tools mentioned on this page
- Questions
What is FFmpeg, and why does OneMacTools use it?
FFmpeg is a widely used open-source program for reading, converting and editing audio and video. It understands far more formats and codecs than macOS does on its own: WebM and MKV containers, the VP9 and Opus codecs, MP3 encoding, two-pass encoding to hit an exact file size, noise reduction filters and more. Most video apps and websites rely on it behind the scenes.
OneMacTools runs FFmpeg on your Mac, for your files only. Nothing is uploaded: FFmpeg reads the original, writes the result to a temporary folder, and OneMacTools moves the finished file into your output folder. FFmpeg also comes with ffprobe, which OneMacTools uses to read a file’s length, size and codecs when macOS can’t (for example an MKV or WebM file).
FFmpeg is a separate project under its own licence, so OneMacTools doesn’t include it. It’s installed from Homebrew only when you ask, as described in our third-party software terms and privacy policy.
Which OneMacTools tools need FFmpeg?
These tools show a Powered by FFmpeg line in their inspector and won’t run without it:
| Category | Tools that need FFmpeg |
|---|---|
| Video | Compress Video, Compress to Size, Convert Video, Trim Video, Resize Video, Crop Video, Rotate & Flip Video, Change Speed, Mute Video, Replace Audio, Watermark Video, Social Video Presets, Merge Videos, Video to GIF, Extract Frames, Loop, Reverse & Boomerang |
| Audio | Extract Audio, Convert Audio, Clean Up Audio, Trim Audio, Ringtone Maker, Merge & Level Audio |
| Images | GIF to MP4 |
| Download | Download Video (needs yt-dlp as well) |
Tools that use FFmpeg only for one option
- Screen Recorder: saving as GIF uses FFmpeg. Without it, the recording is never lost; it’s saved as an MP4 with the note “Saved as MP4 — GIFs need FFmpeg, which you can install from Settings”.
- Auto Subtitles: Subtitle track (can be switched off) needs FFmpeg. Burned into the picture works without it.
Everything else, including all image, PDF, file, utility and on-device AI tools, Record Audio, Fix HDR Video Colours and the Your Mac screens, uses macOS’s own frameworks and never needs FFmpeg.
How to install FFmpeg on Mac from OneMacTools
OneMacTools installs FFmpeg with Homebrew, the standard package manager for the Mac. If Homebrew is already on your Mac, it’s one click:
- Open any tool that needs FFmpeg, such as Convert Video. An orange banner at the top says This tool needs FFmpeg with “OneMacTools can install it for you with Homebrew.”
- Click Install. The banner shows Installing… while Homebrew downloads and installs FFmpeg. You can keep using other tools meanwhile.
- When it finishes, the banner disappears and the tool is ready. FFmpeg now works for every tool in the list above.
You can do the same from Settings › Helpers: next to FFmpeg, click Install with Homebrew. Once installed, the row shows a green tick and FFmpeg’s location, such as /opt/homebrew/bin/ffmpeg.
Where FFmpeg is stored, and how big it is
Homebrew puts FFmpeg in its own folder: /opt/homebrew on Apple silicon Macs, /usr/local on Intel Macs. OneMacTools doesn’t copy it into the app or your Library. Homebrew also installs the libraries FFmpeg depends on, so the download size depends on what you already have; the first install can take a few minutes on a slow connection.
Using FFmpeg you already have (Homebrew, MacPorts or your own build)
OneMacTools looks for an ffmpeg program in these folders, in order, and uses the first it finds:
/opt/homebrew/bin(Homebrew on Apple silicon)/usr/local/bin(Homebrew on Intel, and many manual installs)/opt/local/bin(MacPorts)
So if you installed FFmpeg yourself with brew install ffmpeg or MacPorts, there’s nothing to do: Settings › Helpers will already show the green tick.
Custom FFmpeg path
If your copy lives somewhere else, for example a static build in your home folder, type its full path into Custom FFmpeg path in Settings › Helpers and press Return. The path must point at the ffmpeg program itself (not its folder) and the file must be executable. A custom path takes priority over the folders above. To read file details, OneMacTools looks for ffprobe in the same folder as the FFmpeg it uses, so keep the two together.
Formats and codecs FFmpeg unlocks
With FFmpeg installed, these are the formats OneMacTools’ conversion tools write:
| Output | Video codec | Audio codec |
|---|---|---|
| MP4 and MOV | H.264 (yuv420p, plays everywhere), optimised for streaming | AAC 160 kbps |
| MKV | H.264 | AAC 160 kbps |
| WebM | VP9 | Opus 128 kbps |
| MP3 | MP3 (LAME, high-quality VBR) | |
| M4A | AAC 192 kbps | |
| WAV / AIFF | 16-bit PCM | |
| FLAC | FLAC (lossless) |
Convert Video takes MP4, MOV, WebM, MKV and M4V files in and writes MP4, MOV, WebM or MKV. Convert Audio writes MP3, M4A, WAV or FLAC. Compress to Size uses two-pass encoding so the result lands under the size you choose. For walk-throughs, see MOV to MP4 on Mac and compress a video for email.
Other helpers: yt-dlp, WebP tools and Ghostscript
Settings › Helpers lists three more open-source programs that a handful of tools rely on. They install the same way, from the tool’s banner or Install with Homebrew:
| Helper | Needed by | Why |
|---|---|---|
| yt-dlp | Download Video | Fetches the video from the link you paste. |
| WebP tools | Convert to WebP | macOS can read WebP but not write it. |
| Ghostscript | PDF to PDF/A | Writes archival PDF/A files. |
Updating FFmpeg
OneMacTools doesn’t update FFmpeg on its own; Homebrew owns it. To update, open Terminal and run brew upgrade ffmpeg. OneMacTools picks up the new version the next time a tool runs, with no restart needed. The same goes for yt-dlp: if Download Video says a site refused the download or a file came down without a picture, its message suggests running brew upgrade yt-dlp.
Updating OneMacTools itself (OneMacTools › Check for Updates…) never removes or replaces FFmpeg.
FFmpeg not working? Fixes for common problems
| What you see | What to do |
|---|---|
| “FFmpeg isn’t installed. Install it from the banner above or in Settings.” | Click Install on the banner, or Settings › Helpers › Install with Homebrew. |
| “Homebrew isn’t installed…” | Install Homebrew from brew.sh, or enter a Custom FFmpeg path. |
| “Couldn’t install FFmpeg: …” | Homebrew reported an error. Run brew doctor in Terminal, fix what it lists, then try again; or run brew install ffmpeg yourself to see the full output. |
| Custom path entered but no green tick | Check the path ends in ffmpeg, the file exists, and it’s executable. Press Return in the field to re-check. |
| “A switchable subtitle track needs FFmpeg…” | Install FFmpeg, or choose Burned into the picture in Auto Subtitles. |
| A screen recording saved as MP4 instead of GIF | FFmpeg wasn’t found, or making the GIF failed. Install FFmpeg, then convert the MP4 with Video to GIF. |
If a job fails for another reason, the message appears in the tool and in History. The troubleshooting guide covers every other error by symptom.
Tools mentioned on this page
Questions
Is FFmpeg free and safe to install on a Mac?
Yes. FFmpeg is free, open-source software used by countless apps. OneMacTools installs the standard Homebrew package from Homebrew’s official source, and FFmpeg only ever runs on your own files, on your Mac.
Does OneMacTools work without FFmpeg?
Yes. Image, PDF, file, utility and on-device AI tools never need it, and neither do the Your Mac screens. Only the video and audio tools listed on this page, GIF to MP4 and Download Video require FFmpeg.
Can I use FFmpeg without Homebrew?
Yes. Download or build FFmpeg any way you like, then enter the full path to the ffmpeg program in Settings › Helpers › Custom FFmpeg path. OneMacTools also finds MacPorts copies in /opt/local/bin automatically.
How do I uninstall FFmpeg?
Run brew uninstall ffmpeg in Terminal. OneMacTools will show the install banner again next time you open a tool that needs it. Uninstalling doesn’t affect results you’ve already made.
Why does OneMacTools still say FFmpeg is missing after I installed it?
It only looks in /opt/homebrew/bin, /usr/local/bin and /opt/local/bin, plus your custom path. If your copy is elsewhere, enter its full path in Settings › Helpers and press Return.
Can OneMacTools convert MKV or WebM to MP4?
Yes, once FFmpeg is installed. Drop the MKV or WebM files on Convert Video and choose MP4; the result uses H.264 video and AAC audio, so it plays in QuickTime, Photos, iPhone and nearly every app and website. A batch of files converts one after another into one dated folder.
Do I need ffprobe as well as FFmpeg?
Homebrew installs ffprobe alongside FFmpeg automatically. OneMacTools uses it to read the length, size and codecs of files macOS can’t open itself, such as MKV, so progress and time left are accurate. If you use a custom path, keep ffprobe in the same folder.
Does OneMacTools bundle FFmpeg?
No. FFmpeg is a separate open-source project with its own licence, so it’s installed from Homebrew only when you ask, and kept up to date by Homebrew rather than the app.
