AVI to MP4 Converter

Convert AVI video to MP4 for easier playback on iPhone, Android, Mac, Windows, browsers, TVs, editors, and upload forms. Free, no signup, and files up to 1 GB.

Or drop files here. Max file size 1GB.

Input format

AVI video container

AVI is a container, not a video codec. An .avi file can contain DivX, Xvid, MJPEG, H.264, or other video alongside PCM, MP3, AAC, or no audio, so the extension alone does not determine playback support.

Output format

MP4 video container

MP4 is also a container. For broad browser, phone, and Apple playback, the most useful combination is usually H.264 video with AAC audio inside the MP4 file.

How to convert AVI to MP4 online

Upload an AVI when its older container or codec combination will not play, import, share, or upload where you need it. Convertr starts the conversion immediately after upload on a healthy compatible worker.

The converter keeps the source resolution and frame rate by default. You can open the existing settings before conversion if you intentionally want to change quality, bitrate, resolution, frame rate, video codec, or audio codec.

1 Upload your AVI video or drag it into the converter.
2 Keep MP4 selected as the output format.
3 Open settings only if you want to change quality, bitrate, resolution, frame rate, or codecs.
4 Start the AVI to MP4 conversion.
5 Download the MP4 when processing is complete.

Each AVI upload can be up to 1 GB. Full HD and larger source dimensions remain available; Convertr does not lower resolution merely to reduce server load.

AVI to MP4 conversion for playback problems

Use the direct converter for an .avi file, or open the codec guidance when a media-inspection tool identifies the codec inside another container.

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What happens to the codecs inside an AVI?

The container can change without every stream being treated the same way. The source codecs and your selected settings determine whether Convertr can remux or needs to re-encode.

DivX, Xvid, and MJPEG AVI files

These older AVI video codecs are re-encoded to H.264 for the MP4 output. PCM and other audio that is not suitable for the compatibility path is encoded to AAC; an AVI with no audio remains a video-only MP4.

AVI files already using H.264

When an AVI already contains browser-safe H.264 video and compatible AAC or MP3 audio, and you have not requested a transform, Convertr can remux the streams into MP4 without re-encoding them.

Compatibility is not a compression promise

Converting to MP4 does not guarantee a smaller file. Size can increase or decrease according to the source codecs, duration, resolution, motion, and the quality, bitrate, and codec settings you choose.

Quality depends on remuxing or re-encoding

Remuxing compatible streams does not recompress their picture or sound. Re-encoding DivX, Xvid, MJPEG, or incompatible audio is lossy, so keep the source resolution and choose a higher quality or bitrate when preservation matters.

AVI to MP4 FAQ

Are AVI and MP4 video codecs?

No. AVI and MP4 are containers that can hold different video and audio codecs. Playback depends on both the container and the codecs inside it.

Why does an AVI file not play on my phone, browser, or Mac?

Many AVI files contain older DivX, Xvid, or MJPEG video, PCM audio, or a stream combination that modern browsers, phones, QuickTime, and Apple apps do not accept. An MP4 with H.264 video and AAC audio is a more broadly supported playback target.

Does converting AVI to MP4 reduce quality?

It depends. A compatible H.264 AVI can be remuxed without recompressing the streams. DivX, Xvid, MJPEG, and incompatible audio require lossy re-encoding, so output quality depends on the source and your selected quality or bitrate settings.

Will the converted MP4 always be smaller than the AVI?

No. AVI and MP4 are containers, so file size is controlled mainly by the codecs, bitrate, resolution, frame rate, duration, and content. Converting for compatibility can produce a smaller or larger file.

Can I convert AVI files with PCM, MP3, or no audio?

Yes. AVI files with PCM audio, MP3 audio, and no audio can produce playable MP4 output. Incompatible audio is encoded to AAC, while a source without audio remains without audio.

Does AVI to MP4 conversion keep the frame rate and resolution?

By default, the converter keeps the source frame rate and full source resolution, including unusual rates such as 23.976 or 29.97 fps. Use the existing settings only when you want to change them.

Can I convert a large AVI file online?

Yes. The upload limit is 1 GB per file. Conversion starts after upload without registration, and full-resolution output remains available for Full HD and larger videos.