AVI to MP4 Converter
Turn old AVI videos into MP4 that plays on iPhone, Mac, in browsers, on TVs and in social apps. Free, with no account and no watermark.
Output: MP4 with H.264 video and AAC audio, the most widely supported combination.
Need more changes? Continue in the full editor after downloading or processing the converted file.
How to convert AVI to MP4
The converter re-encodes the video into a standard MP4 file. You do not need to choose a codec, quality or resolution.
Step-by-step
- Choose an AVI file or drag it onto the upload area.
- Wait for the upload to finish, then click Convert to MP4.
- Wait while the video is converted. Long videos take longer.
- Download the MP4 and play, edit or share it where the AVI did not work.
What you get
The result is built for compatibility with today's devices:
- H.264 video with 8-bit 4:2:0 color, converted from DivX, Xvid, Motion JPEG, DV or another codec inside the AVI. Practically every phone, computer, TV and browser can play it.
- AAC audio, the standard audio format for MP4, converted from MP3, uncompressed PCM or other audio formats common in AVI.
- The correct shape of the picture. DV and DVD video stores non-square pixels, and the MP4 keeps that information, so a 4:3 or 16:9 picture is not stretched or squeezed.
- The original resolution and frame rate. An odd width or height is rounded down by one pixel, because H.264 needs even dimensions.
- Fast start for the web: the MP4 can start playing in a browser before it has fully downloaded.
Why an AVI file may not play
AVI is a container Microsoft introduced in 1992, long before smartphones and online video. On Apple devices, support depends on the app and the codec inside: the iPhone Photos app does not play AVI, and QuickTime Player and iMovie usually reject DivX and Xvid files. Browsers cannot play AVI at all, so a website or online course cannot show it, and many upload forms and social apps reject the file.
Even where AVI is supported, the codec inside can be the problem. Many AVI files from the 2000s use DivX or Xvid, which most phones, browsers and modern TVs do not decode, so the player shows an error, a black screen or only plays the sound. Renaming the file to .mp4 does not change the codec. The video has to be re-encoded, which is what this converter does.
Where AVI files come from
Typical sources are digital cameras from the 2000s, which recorded clips in Motion JPEG; MiniDV camcorders, whose tapes were transferred to a computer as DV AVI files; DivX and Xvid videos from the same era; old screen and game recorders; and some dashcams and security cameras.
Motion JPEG, DV and uncompressed AVI files use very simple compression, so they are large: DV takes about 13 GB per hour. In MP4 with H.264 the same video is usually several times smaller with little visible difference, which makes old family videos much easier to store, send and watch on a phone.
When to convert AVI to MP4
Convert when the AVI has to work on a current device or service:
- Watching an old video on an iPhone, iPad, Mac or smart TV that does not open the file or plays it without picture.
- Uploading to a social app, website, LMS or cloud service that accepts only MP4 or plays only MP4 in the browser.
- Editing in iMovie, Final Cut Pro or other software that does not import AVI or its codec.
- Sharing digitized family videos with relatives in a format that opens on any phone.
Quality, file size and limits
DivX and Xvid files are already compressed, so convert once from the original AVI and keep it. Video from DV camcorders and TV captures is often interlaced; the converter does not deinterlace it, so fast motion can show thin horizontal lines, just as in the original on a computer screen.
Files can be up to 200 MB. That covers camera clips and short videos, but DV reaches 200 MB in about a minute, and a typical DivX film is around 700 MB. For longer recordings, open the video in the full Deus Video online editor: it accepts files up to 1 GB, with no size limit on the Maxi plan, and exports MP4.
Compress, trim or convert the MP4
WMV to MP4 Converter
Turn a WMV video into an MP4 that plays on Mac, phones and in browsers.
Compress Video
Make the MP4 even smaller for sending by email or messenger.
Trim Video
Keep only the part of an old recording you want to share.
Convert Video Format
Choose MOV, WebM, MKV or another output format instead of MP4.
Need to Edit Your Video?
Continue with trimming, resizing, cropping, text, subtitles, audio, and other edits in the full editor.
Learn more about AVI and MP4
Frequently Asked Questions
Common questions about converting AVI files to MP4.
Is the AVI to MP4 converter free?
Yes. It is free, you do not need an account, and the MP4 has no watermark.
Will converting AVI to MP4 reduce quality?
The video is re-encoded, so it is not lossless, but the settings keep the original resolution, frame rate and picture shape and aim to keep the difference hard to see. Keep the original AVI and convert from it rather than from an already converted copy.
Why is the MP4 so much smaller than the AVI?
Many AVI files, especially from cameras and camcorders, use Motion JPEG or DV, which compress each frame separately and take a lot of space. H.264 compresses far more efficiently, so the MP4 is often several times smaller with little visible loss.
Can I convert a DivX or Xvid video?
Yes. DivX and Xvid inside an AVI are converted to H.264, which plays on phones, browsers and TVs without extra codecs. This page accepts files up to 200 MB; for a full-length film, use the full online editor, which accepts up to 1 GB, or files of any size on the Maxi plan.
Can I play an AVI on an iPhone or Mac?
Usually not with the built-in apps: the iPhone Photos app does not play AVI, and QuickTime Player and iMovie on a Mac open only some AVI files, depending on the codec; DivX and Xvid usually fail. Convert it to MP4 here, in Safari or any other browser, and the video opens in the standard apps.
Is there a file size limit?
Yes, files can be up to 200 MB. For larger recordings, such as long DV tapes or full-length films, use the full Deus Video online editor: it accepts files up to 1 GB, with no size limit on the Maxi plan, and exports MP4.