ffmpeg & codecs

The engine renders every frame itself; FFmpeg is the separate program that encodes those frames into MP4, WebM, MOV and GIF files. Since 1.0.1 every installer ships it, so video export works out of the box — there is nothing to install. (Before 1.0.1 it had to be on your PATH.)

Which formats use it

So if FFmpeg is ever unavailable, stills, image sequences and WAV audio still export.

The copy that ships

Each installer carries one pinned build of FFmpeg 9.0.2 in <app resources>/ffmpeg/ — for Windows x64, and for macOS on Apple silicon and Intel. Packaging checks it against a SHA-256 pin, runs it, and confirms it has every encoder export uses; a package without it is refused, and the release build checks that it is in every installer and matches the engine’s processor.

When video export needs a repair

A shipped copy can still go missing or stop working on a particular machine — security software quarantines or blocks it, a disk error damages it. Premation does not wait for an export to find that out:

• It checks at startup, and before every export that encodes. Each check actually runs FFmpeg rather than only looking for the file.
• If the copy that should work does not, a notice says Video export needs a quick repair, once per session, with a Fix button.
• When you export a format that needs FFmpeg and it is not ready, the Fix video export dialog opens before you choose where to save. Once it is fixed, Continue carries on with the export; Cancel export stops.
• Window ▸ Customize… ▸ Appearance ▸ Video Export shows the state any time: Working with the copy in use (Built in, Repaired copy, Your FFmpeg, FFMPEG_PATH or System FFmpeg), Check again, and Fix… when it is not working. Some video formats unavailable means a copy runs but lacks an encoder some formats need.

The Fix video export dialog

It says what is wrong in plain terms — the file is missing, security software is stopping it, it was built for a different processor, it is damaged, it did not respond, or it was built without what a format needs — and offers one main action: Download and fix, with the download size on the button.

That downloads the same pinned build the installer ships, checks the free disk space and the SHA-256, installs it into Premation’s own user-data folder (tools/ffmpeg/), and runs it to make sure it works, ending with Video export works again. You can keep working while it runs. The download goes through your system’s proxy settings, and an interrupted download continues where it left off on Try again.

If the download cannot happen, the dialog says why in one sentence and offers the next step:

Choose file… accepts an ffmpeg executable (ffmpeg.exe on Windows) or the pinned .zip. A copy you chose shows as Your FFmpeg in Settings, with Use built-in to go back. Technical details at the bottom of the dialog holds the raw reasons, for a support request.

Failed exports say what to do

When an export does fail, the failed job says why in one sentence, with the button that helps:

Which copy is used

The check tries these in order and uses the first that runs with every encoder export needs (failing that, the first that runs at all):

1. $FFMPEG_PATH, if set.
2. A copy you chose with Choose file….
3. The copy shipped with the app, <app resources>/ffmpeg/ffmpeg[.exe].
4. A repaired copy the app downloaded.
5. ffmpeg on your PATH.

Proxy generation uses the same copy as export. The command line uses $FFMPEG_PATH if set, then the copy shipped with the app, then PATH.

Pointing at a specific build

export FFMPEG_PATH=/path/to/ffmpeg

FFMPEG_PATH takes priority over everything else, provided it runs.

Building from source

A development run (npm run electron:dev:local) has no shipped copy, so export uses FFMPEG_PATH, a copy you chose, a repaired copy or ffmpeg on your PATH — Video Export ▸ Fix… works here too. To put one on your PATH:

winget install Gyan.FFmpeg

brew install ffmpeg

Packaging fetches the pinned build itself. npm run dist:local (and the other packaging scripts) download the archive pinned in electron/ffmpegManifest.json for each platform and architecture into build/.cache/ffmpeg/, check its SHA-256, extract the executable, run it to check its encoders (where the build machine can run it), and stage it with its licence into the package. A failure stops the build. PREMATION_PACKAGE_WITHOUT_FFMPEG=1 allows an offline local rehearsal without it — the packaged app then offers the repair download on first export; the release build ignores that setting.

Licence

The shipped FFmpeg is a GPL build, chosen because export uses libx264, libvpx-vp9 and libopus, which an LGPL build does not have. It runs as a separate program, and its licence text and a pointer to its source (LICENSE.txt, NOTICE.txt) ship beside it in <app resources>/ffmpeg/. If you distribute your own package of Premation, those terms travel with the binary.

Why a separate process

The engine renders each frame and pipes it straight into an FFmpeg child process. Two things follow:

• The encode never competes with the editor’s interface, so a long export leaves the app usable.
• Only a few frames are in memory at once. The finished file is moved into place, so a multi-gigabyte export never passes through the app’s memory.

Related

• Export formats
• Render queue
• System requirements