What does Video Converter do?
Convert video files in your browser between MP4, WebM, MOV, MKV and AVI. Re-encode or copy streams without quality loss, and optionally remove audio.
- Price
- Free
- Account
- Not required
- Processing
- Entirely in your browser; your data and files are not uploaded
- Works on
- Any modern browser on desktop, tablet or phone
- Category
- Video and Audio Tools
How to use the video converter
- Drop a video (MP4, MOV, WebM, MKV or AVI, up to 300 MB).
- Choose the output format: MP4, MOV or MKV (H.264 and AAC), WebM (VP8 and Opus) or AVI (MPEG-4 and MP3).
- Turn on "Keep original streams" to remux without re-encoding when the new container supports the original codecs.
- Optionally remove the audio, then click Convert and download the result.
How it works
FFmpeg reads the first video stream and first audio stream. MP4, MOV and MKV are encoded with libx264 (-preset veryfast -crf 23, yuv420p) and AAC at 160 kbps. WebM uses libvpx (VP8) with the realtime deadline, and Opus audio at 128 kbps. AVI uses MPEG-4 Part 2 (Xvid tag) with MP3 audio. With "Keep original streams", FFmpeg runs -c:v copy -c:a copy, which rewrites only the container.
Assumptions
- Stream copy works only when the target container supports the source codecs (for example H.264 into MKV or MOV). Otherwise it fails and you should re-encode.
- Re-encoding is lossy; the Quality setting maps to CRF 20, 23 or 28 for H.264 and to comparable settings for the other encoders.
- Subtitles, chapters and extra audio tracks are not carried over.
Frequently asked questions
Are my files uploaded?
No. The file is processed by FFmpeg compiled to WebAssembly, running inside your browser. Only the engine itself is downloaded (once, from cdn.jsdelivr.net); your video, audio or images never leave your device.
What is the difference between converting and copying streams?
Converting decodes every frame and encodes it again in the new codec, which is slow and slightly lossy. Copying streams keeps the compressed video and audio exactly as they are and only changes the file container, so it is fast and lossless, but only works when the new container supports the original codecs.
Why VP8 and not VP9 for WebM?
The VP9 encoder in the WebAssembly build of FFmpeg used here crashed in our tests, so WebM output uses VP8, which every browser that plays WebM supports. VP9 files are smaller at the same quality; use a desktop tool if you need them.
How do I make a GIF?
Use the Video to GIF tool, which builds an optimised colour palette for better looking GIFs.
Why does the first run take longer?
The first time you use any of the video and audio tools, your browser downloads the FFmpeg engine, about 31 MB. It is stored in your browser, so later runs on this device start without downloading it again unless you clear site data.
Limitations
- FFmpeg runs as single-threaded WebAssembly in the browser, which is much slower than desktop FFmpeg. Processing time depends on the file length, resolution and your device; long HD videos can take many minutes.
- Browsers limit how much memory a page can use. Very long or high resolution files can fail with an out of memory message, especially on phones and tablets.
- Files up to 300 MB are accepted.
- Your browser may not be able to preview MKV or AVI files; download them to play in a desktop player.