Convert videos to MP4, WebM, MOV or MKV
Change a video’s format in seconds. When the codecs allow it, the streams are copied without re-encoding, so the quality stays exactly the same.
- No upload
- No watermark
- No file size limit
- Hardware accelerated
Drop videos here to convert them
MP4, MOV, WebM, MKV, AVI and more · no size limit or watermark
Processed on your device. Your videos are never uploaded.
Advanced: codec, frame rate, audio, trim
How to convert a video
- 1
Add your videos
Drop in MP4, MOV, WebM, MKV and other video files – as many as you like.
- 2
Choose the output format
MP4 plays everywhere, WebM is made for websites, MOV suits Apple editing apps and MKV is a flexible archive format. MP3 saves only the audio.
- 3
Keep “Original” quality
Original copies the video without re-encoding when the new format supports its codec. Pick a quality level instead if you also want a smaller file.
- 4
Convert and download
Converted files keep their names with the new extension. Download them one by one or together as a ZIP.
Lossless conversion when possible
A video file is a container (MP4, MOV, MKV, WebM) holding compressed streams (for example H.264 video and AAC audio). Many conversions only need a new container: the streams are copied into it bit for bit. This “remux” takes seconds even for long videos and loses no quality at all.
When the target format can’t hold the original codec – say, H.264 video going into WebM – Asset Compressor re-encodes with the best codec your browser supports, at high quality.
Which format should I choose?
MP4 with H.264 is the universal choice: it plays on every phone, computer, smart TV, social network and messaging app. WebM with VP9 or AV1 is designed for websites and is often smaller at the same quality, but some Apple and Windows apps won’t open it.
MOV is Apple’s QuickTime format and is handy for Final Cut Pro and iMovie. MKV can hold almost any codec and is popular for archiving. MP3 extracts just the soundtrack.
Older formats like AVI, WMV and FLV
Browsers can’t read some older formats natively. For these, Asset Compressor switches to a compatibility engine – FFmpeg compiled to WebAssembly – that still runs entirely on your device. It downloads once (about 30 MB, then cached) and is slower than hardware encoding, so it is only used when needed.
Frequently asked questions
Does converting a video reduce its quality?
Not when the streams can be copied, which is the case for most MOV, MP4 and MKV files with H.264 or HEVC video. If re-encoding is needed, the default high quality setting keeps the difference practically invisible.
Are subtitles and extra audio tracks kept?
Asset Compressor keeps the main video and audio track. Subtitle tracks, extra languages and chapters are not carried over.
Can I convert several videos at once?
Yes. Add as many as you like; they are processed one after another so your device stays responsive, and you can download them together as a ZIP.
Which browsers are supported?
Chrome, Edge, Opera and Samsung Internet, Safari 16.4 or newer and Firefox 130 or newer use fast, hardware-accelerated encoding. Other browsers fall back to a slower compatibility mode that still runs entirely on your device.
Are my videos uploaded?
No. Conversion happens in your browser tab and your files never leave your device.
Related tools
MOV to MP4
iPhones and QuickTime save videos as MOV. Turn them into MP4 files that play on Windows, Android and every website – usually without re-encoding.
WebM to MP4
WebM files from screen recorders and browsers often won’t open in editors, on iPhones or in PowerPoint. Convert them to universally compatible MP4 in your browser.
Video to MP3
Save the soundtrack, a podcast recording or a voice memo from any video as an MP3 file that plays everywhere – processed entirely on your device.
Last updated