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# Convert MOV to WebM with VP9 and Vorbis (royalty-free, browser-ready)
- URL: https://ffmpeguru.com/convert-mov-to-webm-with-vp9-and-vorbis-royalty-free-browser-ready/
- Published: 2026-10-15T09:00:00.000Z
- Updated: 2026-10-15T09:00:00.000Z
- Author: FFmpeguru
- Tags: ffmpeg

WebM is the format to reach when the destination is a browser and you want to avoid H.264 licensing entirely. VP9 video and Vorbis audio play in every modern browser, the container is royalty-free, and quality at a given bitrate is excellent.

## The command

```
ffmpeg -i input.mov -c:v libvpx-vp9 -c:a libvorbis output.webm
```

## What it does

FFmpeg decodes the MOV (typically ProRes or H.264 + AAC on macOS), re-encodes the video to VP9 via libvpx, re-encodes audio to Vorbis, and muxes both into the WebM container. Defaults are reasonable but conservative; for production you almost always want to set a target bitrate or CRF.

## When to use it

Whenever the target is a browser and you want a fully open pipeline. WebM/VP9 is also a good archival format because it is patent-unencumbered. For a balance of quality and size, add `-b:v 0 -crf 30 -b:a 128k` for a constant-quality encode.

## Video and audio requirements

VP9 is a software codec, so encoding is slow without hardware acceleration. Audio can stay Vorbis or be transcoded to Opus for better speech quality. VP9 supports 8-bit and 10-bit; specify `-pix_fmt yuv420p10le` for 10-bit HDR sources.

## Things to avoid

- Expecting real-time encoding on a CPU. VP9 is roughly an order of magnitude slower than H.264; budget accordingly or use a GPU (NVENC VP9 exists on recent NVIDIA hardware).
- Leaving the default quality. The default CRF 32 is blocky; 24 to 28 is the sweet spot for delivery.
- Forgetting `-row-mt 1` for multi-threaded encoding on large frames. Without it libvpx uses a single thread and encodes crawl.
- Using WebM for iOS delivery. Safari supports it but not in all contexts, and AirDrop and many iOS video apps do not.