Transparent WebM to ProRes 4444.
Editing software prefers ProRes 4444 for footage with transparency. Upload a WebM with an alpha channel and download a MOV your editor reads without a black background.
Good to know.
Will the transparency survive?+
Yes: the output is ProRes 4444 with an alpha plane, and every file is checked for real transparent pixels before you can download it. Import it in After Effects with Alpha set to Straight.
Why is the MOV so much bigger?+
ProRes is an intra-frame editing codec. Expect roughly 10–20 MB per second at 1080p (12.5 MB/s in our test), so a 15-second clip is around 200 megabytes. Keep the WebM for the web.
What is the FFmpeg equivalent?+
ffmpeg -c:v libvpx-vp9 -i input.webm -c:v prores_ks -profile:v 4444 -pix_fmt yuva444p10le -qscale:v 4 output.mov. The -c:v libvpx-vp9 before -i matters: FFmpeg’s default VP9 decoder silently drops the alpha channel.
What if my video has no transparency?+
Then there is no alpha to keep: converting an ordinary MP4 only produces an opaque file. The converter says so instead of guessing. Use the AI video background remover first, then convert the result.
Is it really free?+
Yes. Sign in with Google and convert up to 10 files a day without credits. Files up to 15 seconds, 1080p, 30 fps and 100 MB. Results stay in My videos for 7 days.