MPEG4 to MP4
Convert MPEG4 to MP4 that actually plays: MPEG-4 Part 2 video (DivX, Xvid, old cameras) is re-encoded to H.264. Free, no sign-up, no watermark.
- Free & unlimited
- No sign-up
- Files never uploaded
- No watermark
- Up to 2 GB per file
How to convert MPEG4 to MP4
Everything runs in this tab. The first visit downloads the converter (about 32 MB) once; later visits load it from cache.
- 1
Pick the old video
Drop a .mp4, .avi, .divx, .xvid or .mpeg4 file. Its size, duration and resolution show up at once, so you know you grabbed the right clip.
- 2
Keep Re-encode on
This page starts in Re-encode, which rebuilds the picture as H.264. Choose High, Medium or Small file, and optionally scale down to 1080p, 720p or 480p. Your choices are remembered for the next file.
- 3
Save the H.264 file
When it finishes you see the old and new size side by side. The download keeps the file name, ends in .mp4 and starts playing before it has fully loaded.
What this MPEG-4 converter fixes
The trouble with these files is the codec inside, not the extension, so that is what gets changed.
The codec changes, not just the label
Re-encode turns MPEG-4 Part 2 into H.264 (MPEG-4 Part 10, also called AVC). That is the step that makes an iPhone, a browser or an editor accept the file.
Usually smaller, too
H.264 packs more picture into fewer bytes than DivX-era encoders. In our test a 6-second Xvid AVI went from 329 KB to 144 KB. Your savings depend on the source.
Sound comes along
Re-encode writes AAC audio at 192 kbps, the format every MP4 player expects. Every audio track in the file is kept, and so are chapters.
Your camera roll stays put
There is no upload step, so a folder of old family clips never passes through someone else's server and never waits on an upload bar.
MPEG-4 Part 2 vs H.264 vs the MP4 container
Three different things share the name MPEG-4. This is how they line up.
| MPEG-4 Part 2 (ASP) | H.264 (Part 10, AVC) | MP4 (Part 14) | |
|---|---|---|---|
| What it is | A video codec | A newer video codec | A container that holds video and audio |
| Also known as | DivX, Xvid, MPEG-4 Visual | AVC (encoded here with x264) | MPEG-4 file, .mp4 |
| Where you meet it | 2000s movie rips, early digital cameras and phones | Most video made in the last 15 years | Almost every video download and phone export |
| Plays on current iPhones, browsers, editors | Often refused | Yes | Depends on the codec inside |
| What this page does with it | Re-encodes it to H.264 | Copies 8-bit 4:2:0 H.264 untouched in Fast Copy | Writes it, web-optimized |
Files that need an MPEG-4 to MP4 fix
Each of these usually means MPEG-4 Part 2 video, which an MPEG4 to MP4 re-encode fixes.
A DivX or Xvid movie folder
Rips from the early 2000s are usually .avi or .divx files with Xvid or DivX video. Re-encoding gives you files a smart TV app or tablet player accepts.
Clips from an early digital camera
Many point-and-shoot cameras recorded short MPEG-4 movies next to the photos. As H.264 they drop straight into a modern photo library.
Videos from an old phone
Pre-smartphone and early smartphone handsets often saved MPEG-4 Part 2 clips. Convert them once and they play in current messaging apps.
An editor that rejects the import
Editing apps tend to expect H.264. When a clip imports with no picture or an unsupported-format error, re-encode it and import the new file.
A browser upload that fails
Web players decode H.264, not Part 2. Convert before uploading to a site, a course platform or a shared drive preview.
An .mp4 that won't open
The extension says MP4, but the phone or browser won't play it. One common reason is Part 2 video inside.
Is MPEG-4 the same as MP4?
Not quite. MPEG-4 is a family of standards, and three parts matter here. Part 14 defines the MP4 file itself, the box that holds the streams. Part 10 is H.264, the video codec nearly everything plays. Part 2 is the older codec behind DivX and Xvid, also used by many digital cameras and phones of the 2000s.
So a file can end in .mp4 and still carry Part 2 video. Many current players, iPhones, browsers and editors refuse that combination even though the extension looks right. Converting MPEG4 to MP4 here really means swapping Part 2 for H.264 while keeping the MP4 container.
MPEG4 to MP4 mistakes to avoid
Mistake: Renaming .avi or .divx to .mp4.
Do this instead: The extension changes, the Part 2 video does not. Players that refused the file before will refuse it again.
Mistake: Switching to Fast Copy to save time.
Do this instead: Fast Copy puts the Part 2 stream into an MP4 untouched, in seconds, but it still won't play where it failed before. Use it only when the target device already handles DivX or Xvid.
Mistake: Squeezing decade-old clips with Small file.
Do this instead: Old low-resolution footage has little detail to spare, and CRF 28 removes more of it. Pick High (CRF 18) for anything you plan to keep.
Mistake: Bringing an .mpg file to this page.
Do this instead: MPG files hold MPEG-1 or MPEG-2 video, a different codec family. Use the MPG to MP4 converter for those.
Cost, privacy and limits of this converter
Free, unlimited conversions
No sign-up, no watermark, no cap on how many files you convert. Each file is converted on its own; there is no batch queue.
Nothing is uploaded
Your file is converted on your own device and is never uploaded to our servers. The only download is the converter program, delivered by jsDelivr.
A 2 GB ceiling per file
Browser memory sets the ceiling. A 1.6 GB file converted in our tests; a 2.1 GB file stopped with an out-of-memory message.
Standard FFmpeg underneath
The engine is FFmpeg 5.1.4 compiled to WebAssembly, unmodified, so it reads DivX and Xvid streams the same way desktop FFmpeg does.