Video Converter

Convert video between MP4, MOV, MKV, WebM, AVI, FLV, WMV, MPG, 3GP and OGV, or pick an iPhone, Android, console or PSP preset. Runs in your browser.

The interactive tool loads here when JavaScript runs.

About this tool

What is Video Converter?

This converter rewrites a video into another container and, unless you ask it not to, re-encodes the picture and sound with codecs that suit the target. Pick MP4 and you get H.264 with AAC audio; pick WebM and you get VP8 with Opus; pick AVI and you get MPEG-4 Part 2 (the Xvid flavour) with MP3. The note under the format menu always says exactly which codecs will be written, so there are no surprises when a TV or editor opens the file.

Instead of separate "convert for iPhone" or "convert for PSP" pages, the device presets live in one menu. Each preset fixes the container, the maximum resolution, a frame-rate ceiling and the encoder profile. For example, the PSP preset letterboxes to exactly 480x272 at 29.97 fps with H.264 Main profile, because that handheld refuses anything else.

The work is done by ffmpeg compiled to WebAssembly and running in your browser tab. The engine itself, about 32 MB, is downloaded from the jsDelivr CDN the first time you convert; your video is read straight from disk into that engine and the result is written back to memory, so the file is never uploaded anywhere.

  • 11 output containers with the codecs named up front
  • Device presets for iPhone and iPad, Android, Xbox, PS4/PS5, PSP, Wii Photo Channel and old 3GP phones
  • Fast remux mode for lossless container changes
  • Resolution, frame rate, quality, trim and remove-audio options
  • Batch conversion with progress, cancel and download all
  • Files stay on your device; only the ffmpeg engine is fetched from a CDN
Read the guide: Video Formats Explained: Containers, Codecs, Bitrate and CRF

How to use Video Converter

  1. Drop one or more videos on the upload area, or record the 3-second sample to try the tool without a file.
  2. Choose a device preset, or leave it on None and choose an output format. Read the note underneath to see the codecs.
  3. Optionally set a resolution, frame rate, quality, trim start and end, or switch off the audio. Turn on Fast remux to change only the container.
  4. Click Convert. The first run downloads the engine once; after that, each file shows a progress bar and can be cancelled.
  5. Preview the result (for formats your browser can play) and click Download, or Download all for a batch.

Worked examples

iPhone MOV to MP4 without re-encoding

Input

IMG_0412.MOV, H.264 + AAC, 1920x1080, Fast remux on, format MP4

Output

IMG_0412.mp4, same size within a few KB, ready in seconds

The streams are copied, not decoded, so quality is identical and the time taken depends only on how fast the file can be read.

Portrait phone clip for an old PSP

Input

1080x1920 portrait video, preset PSP

Output

clip-psp.mp4, 480x272 with black bars at the sides, 29.97 fps, H.264 Main

The PSP only accepts a few frame sizes, so the picture is shrunk to fit and padded instead of being stretched.

Background and insight

A video file is two layers. The container (MP4, MOV, MKV, AVI) is the box that interleaves streams and stores timing and metadata; the codec (H.264, HEVC, VP8, MPEG-2) is how the pictures inside were compressed. Most "my video will not play" problems are codec problems wearing a container name. An MKV with H.264 inside plays almost everywhere once it is rewrapped as MP4, while an AVI with an exotic codec stays stubborn whatever you rename it to.

That is why the Fast remux switch exists. An iPhone MOV usually holds H.264 or HEVC video and AAC audio, all of which MP4 is allowed to carry, so copying the streams into a new MP4 takes seconds and loses nothing. Re-encoding is only needed when the codecs inside are not allowed in the target (VP9 into AVI, say) or when you want to change size, frame rate or quality.

Some targets are historical. FLV was Adobe Flash's format and Flash Player reached end of life on 31 December 2020; WMV and 3GP survive in old software and phones; MPG here means an MPEG-2 program stream of the kind DVD players and broadcast tools expect. They are offered because people still have hardware that needs them, not because they are good choices for new work. For new files, MP4 with H.264 is the safe default.

One limitation is worth stating plainly: the WebM option writes VP8 rather than VP9. The VP9 encoder in the ffmpeg.wasm build this tool uses crashes on the first frame, so VP8, which every browser that plays WebM also supports, is used instead. The files are larger than VP9 would make at the same quality.

Common use cases

  • Editing software that refuses MKV or WebM

    Rewrap or re-encode screen recordings and downloads as MP4 so Premiere, iMovie or DaVinci Resolve import them.

  • Playing videos on a TV, console or old handheld

    Use the Xbox, PlayStation, PSP or Wii presets to get a file the built-in media player accepts from a USB stick or SD card.

  • Opening legacy archives

    Turn FLV, WMV, 3GP or MPG files from old cameras, phones and websites into MP4 that current devices play.

  • Feeding tools that want a specific format

    Produce OGV for a wiki that only accepts free formats, or MPEG-2 for a broadcast or DVD authoring workflow.

Tips and limitations

  • Single-threaded WebAssembly is several times slower than desktop ffmpeg. Expect roughly real time or slower for 1080p H.264; drop to 720p or 480p if you are in a hurry.
  • Files over about 500 MB may run out of browser memory, especially on phones, and the engine cannot address more than about 2 GB. Use desktop ffmpeg or HandBrake for long recordings.
  • Fast remux only works when the codecs are allowed in the target container. If ffmpeg refuses, switch the remux off and let it re-encode.
  • With remux on, trims snap to the nearest keyframe before your start time, so the clip may start a second or two early. Re-encoding trims precisely.
  • Converting between lossy formats always loses a little detail. Convert from the original recording when you can, not from an earlier conversion.
  • AVI, WMV, FLV, MPG and 3GP will not preview in the browser; the download is still a normal file that VLC and the target devices play.

Frequently asked questions

Is my video uploaded when I convert it here?

No. The page downloads the ffmpeg engine (about 32 MB of WebAssembly) from the jsDelivr CDN, and your file is passed to that engine inside the browser tab. The converted file is created in memory and saved with a normal download. No video data goes to a server.

Why is converting MOV to MP4 so fast with Fast remux on?

Because nothing is re-encoded. MOV and MP4 are close relatives, and the H.264 or HEVC video and AAC audio in a phone recording are allowed in MP4, so the tool copies the compressed streams into a new container. It is lossless and limited only by read speed.

Which device presets are available and what do they write?

iPhone/iPad (MP4, H.264 High, up to 1080p), Android phone (MP4, H.264 Main, up to 720p), Xbox and PS4/PS5 (MP4, H.264 High, up to 1080p at 60 fps), PSP (480x272 MP4), Wii Photo Channel (Motion JPEG AVI, approximate) and old phones (3GP, 320x240). The exact settings are shown under the menu.

Why does WebM output use VP8 instead of VP9?

The VP9 encoder in the ffmpeg.wasm 0.12 build crashes on the first frame, so the tool writes VP8, which every browser that plays WebM also supports. Files come out somewhat larger than VP9 at the same quality. Desktop ffmpeg can make VP9 or AV1 if you need them.

How large a video can the browser converter handle?

Files up to a few hundred megabytes are fine on a desktop. Above about 500 MB the tool warns you, because the engine holds data in browser memory, and above about 1.9 GB it refuses the file. Trimming first or lowering the resolution helps.

Can I convert several videos at once?

Yes. Drop several files and they are converted one after another with the same settings, because the engine runs one job at a time. Each row shows its own progress, error message and download button, and Download all saves every finished file.

Does converting improve the quality of a video?

No. Re-encoding can keep quality close to the source at a high setting, but it cannot add detail that is not there, and upscaling only makes the file bigger. Choose the High quality setting or Fast remux when keeping quality matters.

Is there an in-depth guide to Video Converter?

Yes. “Video Formats Explained: Containers, Codecs, Bitrate and CRF” covers the background, how it works, common pitfalls and worked examples. Read the full guide.

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