Video format convert — MP4 / MOV / WebM stream copy
Change the video container (e.g. mov → mp4) without re-encoding by using ffmpeg.wasm stream copy. Works for codec-compatible combinations only. Supports batch processing and a single ZIP download.
How to use
Drop videos whose container you want to change (mov / mp4 / mkv, etc.). Pick the target extension and click Convert — ffmpeg.wasm stream-copies the video / audio into the new container, finishing almost instantly. Codec / container combinations that aren't compatible (e.g. VP9 in mp4) will fail. Batch processing and a single ZIP download are supported.
FAQ
- Are videos uploaded?
- No. ffmpeg.wasm runs inside your browser; videos never leave your device.
- Does quality drop?
- No. Stream copy preserves the video / audio bytes exactly.
- Why does it fail sometimes?
- The codec may not be valid for the target container (e.g. VP9 in mp4), or the file's MOOV atom is corrupt. Use a re-encoding tool instead in those cases.
- WebM ↔ MP4?
- WebM (VP8 / VP9 + Opus / Vorbis) and MP4 (H.264 + AAC) usually use incompatible codecs, so stream copy fails. You'll need re-encoding.
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