Free Online Video Converter

Convert between MP4, MOV, MKV and WebM in your browser. Streams the target format can hold are copied without re-encoding, so most conversions finish in seconds.

  • 免費
  • 無需註冊
  • 無水印
  • 在瀏覽器裏運行

Video Converter

轉換器是編譯成 WebAssembly 的 ffmpeg。你選第一個文件時它會下載一次（約 30 MB），之後就留在瀏覽器緩存裏。

目標容器裝得下的流會直接複製過去,不重新編碼,畫質不動、幾秒完成。只有目標容器裝不下的部分纔會重新編碼,每一行都會告訴你實際發生了哪種。

文件在你自己的瀏覽器裏處理，不會上傳。引擎本身有 30 MB，只在第一次使用時下載，之後都從瀏覽器緩存裏取。

Video Converter 怎麼用

  1. 1Pick the output format below, then drop one or more videos onto the box above.
  2. 2Each file is inspected first. Streams the target container can hold are copied unchanged; only incompatible ones are re-encoded, and the row says which happened.
  3. 3Download files individually, or grab everything as a zip.

Copy first, encode only when forced

A video file is a box of streams, and most "conversion" jobs only need a different box. This converter is built around that fact: it reads what is inside your file, checks it against what the target container accepts, and copies everything it can. A copied stream costs no time worth mentioning and no quality at all, because no frame is ever decoded.

Re-encoding happens only where it is genuinely forced, such as VP9 video heading into an MP4, or H.264 heading into a WebM. Those runs are slower than real time in a browser, and the interface treats that honestly: the row says re-encoding while it happens, shows a percentage, and the cancel button actually stops the work rather than just hiding it.

Choosing a target, practically

MP4 with H.264 is the least interesting and most correct answer for almost everyone: phones, TVs, browsers, editors and web forms all take it. MOV is worth choosing when an Apple-centric pipeline asks for it by name. MKV holds nearly any stream you throw at it unchanged, which makes it the fast target for archiving odd files. WebM is the open format the Chromium world favours; going to it always re-encodes here, so reserve it for when a platform requires it.

For pulling the soundtrack out of a video there is a dedicated audio converter, and the GIF pages handle animated output, each with the controls that job actually needs.

Limits, stated plainly

Files up to 500 MB are accepted. The first file triggers a one-time engine download whose size the page states up front. Everything runs locally: your footage never leaves your browser, whatever is in it.

常見問題

Which conversions are instant and which are slow?
Anything where the target container can hold the source's codecs is instant, because the streams are copied rather than re-encoded. MOV to MP4, MP4 to MOV and almost everything into MKV fall in that class. Conversions into WebM, and WebM into anything Apple-flavoured, genuinely re-encode and run slower than the clip's duration. The row for each file tells you which kind you got, while it runs and after.
Which output format should I pick?
MP4 unless you have a reason. It plays on effectively everything made in the last fifteen years. MOV matters when a specific Apple-centric workflow demands it, MKV is the archivist's box that holds anything, and WebM serves the open-web stack. If you just need the file to work somewhere, MP4 is the answer.
Does converting lose quality?
A copied stream loses nothing, and is bit-identical to the source. A re-encoded one is compressed again, which costs some quality by nature; the encoder matches its bitrate to the source's resolution and frame rate to keep that loss hard to see. The honest summary is that this tool loses zero quality whenever the formats allow it, and says so per file.
What happens to subtitles and extra audio tracks?
Subtitle and data tracks are dropped, and only the first audio track is kept. Containers disagree wildly about these, and carrying them across unreliably is worse than being clear. If multi-track material matters to you, a desktop tool is the right place for it.
Is there a GIF option?
GIF is deliberately its own page, because it is not really a video format; it needs different controls for frame rate and width. Use our video to GIF tool for that, and the GIF to MP4 page for the reverse.

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