Convert video to MP4, WebM, MKV, MOV or AVI
Upload any common video file, pick an output format and a quality level, and VideoBB re-encodes it with FFmpeg. MP4 is the safe choice for almost every device; WebM suits websites; MKV and MOV suit editing and archiving.
Free with a VideoBB account
Sign in with Google to use the video converter. Your uploads and results stay private to you and are deleted after 24 hours.
How it works
A video file is two things: a container (the .mp4 or .mkv wrapper) and the codecs inside it. Changing only the extension never converts anything, which is why a renamed file often refuses to play. This converter decodes the original and writes a new file with codecs that belong in the container you choose.
Output keeps the original resolution and frame rate. Choose High quality when the file is going into an editor, Balanced for everyday sharing, and Small file when size matters more than detail.
Options at a glance
| Output | Video codec | Audio codec | Best for |
|---|---|---|---|
| MP4 | H.264 | AAC | Phones, TVs, social apps, email, anything |
| WebM | VP9 | Opus | Websites and HTML5 players |
| MKV | H.264 | AAC | Archiving, media servers, multiple tracks |
| MOV | H.264 | AAC | Apple devices and editing apps |
| AVI | MPEG-4 Part 2 | MP3 | Old players and legacy hardware |
Step by step
Upload
Drop a file up to 4 GB. The upload resumes if your connection drops.
Choose
Pick the output format and quality.
Convert
FFmpeg re-encodes the file on our servers; the page shows live progress.
Download
Save the result, or publish it to your channel. Files are deleted after 24 hours.
When to use the video converter
Use the converter when a file will not open where you need it. The problem is the format, not the size or the length. The converter fixes that by writing new codecs into a new container.
If the file plays fine but is too big to send, the video compressor is the better tool, because it aims at a file size. You also do not need to convert before uploading to VideoBB. The list of upload formats and size limits shows what the site takes as it is.
A phone video will not play on a TV or PC
Many phones record HEVC, also called H.265. Some TVs, PCs and editors cannot decode it. Converting to MP4 writes H.264, which almost every device plays. Our comparison of H.264, H.265 and AV1 explains why the older codec still wins on compatibility.
A portrait clip shows up sideways in some players
Phones often save a rotation flag instead of turning the pixels. Some players ignore that flag. The converter applies the flag while it re-encodes, so the new file plays upright in every player. If the clip is wrong on the phone too, use the rotate and flip tool instead.
A website or HTML5 player asks for WebM
WebM with VP9 video and Opus audio is an open format. Pick it when a site or CMS asks for WebM. VP9 takes longer to encode than H.264, so a long file needs more time.
How the quality setting maps to the encoder
Each quality choice sets a constant quality value. A lower number keeps more detail and makes a bigger file. Each codec uses its own scale, so compare numbers down a column, not across a row.
| Quality | MP4, MKV, MOV (H.264 CRF) | WebM (VP9 CRF) | AVI (MPEG-4 scale) |
|---|---|---|---|
| High | 20 | 28 | 2 |
| Balanced | 24 | 33 | 4 |
| Small file | 28 | 38 | 7 |
What the converter keeps and what it changes
The converter aims for a clean file that plays almost anywhere. A few things change on the way.
- It keeps the resolution and the frame rate of the original. An odd width or height is rounded down by one pixel, and video with non-square pixels (DVDs, some camcorders) is stretched to the shape it is shown in.
- It keeps the first video track and the first audio track. Extra languages and subtitle tracks are left out.
- MP4, MKV and MOV get stereo AAC sound at 160 kbps. WebM gets Opus at 128 kbps (surround sound is mixed to stereo), and AVI gets MP3 at 192 kbps.
- MP4 and MOV files are set up for fast start, so playback can begin before the whole file arrives.
- The picture is written as standard 8-bit colour, which every player can show. HDR video is tone mapped to standard colour, interlaced video (DVDs, TV recordings, older camcorders) is deinterlaced, and transparent areas become black.
Fixing common conversion problems
Most problems come from the source file or from the settings. These are the ones people hit most often.
The new file is bigger than the original
This happens when the source was already small and efficient. The converter aims at a quality level, not a size. Pick Small file, or send the result through the compressor with a target size.
HDR video looks less bright than on the phone
The converter writes standard 8-bit video. HDR clips from phones (HDR10 and HLG) are tone mapped on the way, so colours and contrast stay close to the original instead of turning flat and grey. The brightest highlights are toned down, because standard video cannot be as bright as an HDR screen. Our guide to HDR video explains what HDR adds.
Surround sound or a second language is missing
Only the first audio track is kept, and surround sound is mixed down to stereo (AVI, MP4, MKV and MOV always get stereo). Keep the original file if you need 5.1 sound or several languages.
Privacy, limits and file retention
Your upload and the converted file are private to you. Results are kept for 24 hours and then deleted, so download what you need. A free account can run 10 tool jobs in any 24 hours, and Premium raises that to 100.
Frequently asked questions
Does converting reduce quality?
Every lossy re-encode discards some detail, but at the High setting the difference is very hard to see. If you only need a different container and the codecs already fit, the trim tool's fast mode copies streams without re-encoding.
Which format should I pick?
MP4 unless you have a reason not to. It plays on phones, browsers, TVs and editing software. Pick WebM for a website that serves open formats, and MKV when you want a flexible archive.
Why is my AVI or MKV not playing in the browser?
Browsers play a small set of codecs. Older AVI files often use DivX, Xvid or MP3 in ways browsers do not support. Converting to MP4 fixes it.
Does the converter change the resolution?
No. The output keeps the original size and frame rate (an odd width or height is rounded down by one pixel, which H.264 needs). To change the resolution, use the video resizer.
Can I convert several files at once?
No. Each job takes one file. Run the files one after another; each one counts as a job in your daily allowance.
Can I publish the converted video to my channel?
Yes. Publish sends the result to your channel as a private draft, so nobody sees it until you choose. It counts toward your daily upload allowance.
Related guides
More video tools
All toolsShrink a video to a quality level or an exact target size.
Trim videoCut a clip between two timestamps, instantly or frame-accurately.
Resize videoChange resolution from 4K down to 144p, keeping the aspect ratio.
Video to GIFTurn up to 30 seconds of video into a looping GIF.
Extract audioSave a video's soundtrack as MP3, M4A, WAV or Opus.
Mute videoRemove the audio track without re-encoding the picture.
Rotate or flip videoFix sideways or upside-down footage, or mirror it.