Web video workflow
Convert MP4 to WebM on Mac
Neocodec turns a supported MP4 into a WebM file with VP9 video and Opus audio. Run it from the app, a Finder Quick Action, or the bundled command-line tool.
The short answer
Use the WebM VP9 preset
Choose WebM Efficient VP9, add the MP4, and convert. The output uses VP9 video and Opus audio and lands beside the source unless you choose another destination.
Container
WebM
Video codec
VP9
Audio codec
Opus
Preset ID
webm-vp9
App workflow
Create the WebM
Select WebM Efficient VP9
Choose the built-in WebM preset in Neocodec.
Add the MP4
Drop in one file, several files, or a folder. Trim in the app if needed.
Convert and test
Run the job, then play the WebM in the browser or application where you plan to use it.
Terminal option
Put repeat conversions in a script
Install Neocodec's bundled command-line tool from Settings, then run:
neocodec convert --preset webm-vp9 demo.mp4
Add --output-dir ./Converted when you want the result in a specific existing folder. The terminal tool takes files rather than folders, so use a shell pattern for a batch.
Tune WebM
Set VP9 quality, scale, and frame rate once
In Settings ▸ Presets, select WebM Efficient (VP9) and edit CRF, output scale, or the optional frame-rate cap. The saved version is used by the app chip, the Neocodec: VP9 Finder action, and the webm-vp9 command-line preset.
An edited built-in is clearly marked (edited) and can be returned to its original values with Revert to Default.
Before delivery
Keep an MP4 fallback when the audience is unknown
WebM works well in compatible browsers and applications, but native editors and older delivery systems vary. Test the actual destination. For a public website, keeping an H.264 MP4 fallback is a sensible compatibility choice.
Check the codec inside the MP4. Neocodec 1.0.4 does not accept H.265 or HEVC input, even when the filename ends in .mp4.
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