Advibly LogoAdvibly
Free tool

Convert video without handing it over

MOV to MP4, MKV to MP4, MP4 to WebM, or strip the audio out to MP3 or WAV. Codecs your browser cannot encode are shown greyed out rather than failing halfway through.

Your file never leaves this tab. It is read, edited and written by your own browser, so nothing is uploaded and nothing is stored.

Why this one

What this tool gets right

The containers people actually need

MP4, WebM, MOV and MKV for video; MP3, WAV and OGG when you only want the sound. Each one says what it is good for.

Honest codec choices

H.264, HEVC, VP9, AV1, AAC, Opus and the rest, each checked against your browser at your output size. If it cannot be encoded here, it is disabled with the reason.

Container swaps stay fast

Moving an H.264 track from MOV into MP4 changes the wrapper, not the video. Nothing is decoded and the quality is untouched.

Drop a track

Turn the audio off for a silent background loop, or turn the video off and keep the sound. Both are one toggle.

How it works

Three steps, about thirty seconds

01

Drop the file in

Choose a file or drag it onto the page. It opens straight away, because there is nothing to upload.

02

Set it up

Drag the handles or type exact numbers. The preview applies the same operations in the same order the encoder will.

03

Export and download

Your machine does the encoding, with a real progress bar. The file lands in your downloads folder, unmarked.

Containers and codecs are different things

MP4, MOV, MKV and WebM are containers: boxes that hold tracks and describe how they line up. H.264, HEVC, VP9, AV1, AAC and Opus are codecs: the compression inside those tracks. 'Converting to MP4' can mean either putting existing tracks into a new box, which is instant and lossless, or compressing them again with a different codec, which is neither. This tool does the cheap one whenever it can. Leave the codecs on Automatic and it will keep what it can keep, and re-encode only what the target container cannot hold.

What a browser can encode, and what it cannot

WebCodecs gives a page the same encoders the browser itself uses, which usually means hardware H.264 and often HEVC on Apple hardware, plus software VP8, VP9 and AV1. It does not give a page ProRes, DNxHD or any other production intermediate, and it does not give you every profile of every codec. So this suite is excellent at everyday formats and is not a replacement for FFmpeg on a workstation. When something is beyond it, the picker says so before you start rather than after.

What this tool will not do

  • It will not fetch a video from YouTube, TikTok, Instagram or any other platform. You have to have the file.
  • It will not repair a corrupt or partially downloaded file. If a player cannot open it, neither can this.
  • It will not add anything to the picture: no captions, no logos, no filters. It edits the file you brought.
  • Speed is your hardware. A long 4K clip on a phone will take minutes where a laptop takes seconds.

Questions, answered

MP4 unless you have a reason. It plays everywhere and every platform accepts it. WebM is smaller at the same quality and is the only choice here that keeps transparency, but Safari support is patchier and most ad platforms will not take it. MOV is for handing footage to an editor on a Mac. MKV is for keeping unusual codec combinations without re-encoding.
It is when the video track can be carried over as it is, which is the common case for MOV and MKV files holding H.264. It is not when the codec has to change, for example VP9 into MP4: then every frame is decoded and compressed again, and some quality goes. The export button tells you which one is about to happen.
Yes. Pick MP3, WAV or OGG as the container and the video track is dropped automatically. WAV is uncompressed, so it is large but adds no further loss on top of what the source already had.
Because your browser has no encoder for it at the size you are exporting. Encoder support varies by browser, by operating system and sometimes by resolution, so the list is checked against your actual machine rather than assumed.
No. The file is opened by your browser with the File API and rewritten with WebCodecs, the same video machinery your browser uses to play a video. Nothing is sent to a server, so there is no upload wait, no queue and no copy of your file sitting in someone's storage bucket.
There is no limit we impose. The practical ceiling is your machine: the file is read in small pieces rather than loaded whole, so multi-gigabyte sources open instantly, and if you turn on 'write straight to disk' the result never has to fit in memory either. On a phone, expect long clips to be slow.
None of the three. Because the work happens on your machine, this costs us nothing to run, so there is nothing to gate. You get the file you made, unmarked.
Anything current: Chrome, Edge, Safari 17 and up, and Firefox 130 and up. The tools use WebCodecs, so a very old browser will report that it cannot encode, rather than producing a broken file.
Keep going

More free tools

Video metadata viewer

Codec, resolution, bitrate, frame rate and rotation, instantly.

Open tool

Video resizer

Scale a video to an exact width and height, or down to 1080p.

Open tool

Video trimmer

Cut a clip down to the part that matters, on the exact frame.

Open tool

Words are the easy part. Advibly makes the creative.

Advibly turns your brand into finished ads: product-in-hand UGC videos, static image ads, carousels, and explainers. Same thinking as this free tool, pointed at the thing that actually takes time.

Start freeSee pricing