Step 1: Supply your AVI files using the button above or by haul and lay.
Step 2: Click the 'Convert' button to start the conversion.
Step 3: Get your converted MP4 files.
AVI to MP4 Conversion FAQ
What does the AVI to MP4 converter do?
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AVI is a legacy container, often poorly supported on modern devices. Converting to MP4 rewraps the video with a current codec (H.264 / H.265 / VP9) for broad browser, phone, and TV compatibility.
Will resolution and frame rate be preserved in the MP4?
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Yes. AVI → MP4 keeps resolution, frame rate, and aspect ratio unchanged by default. To change them, use the Resize or Speed tool on the result.
My AVI footage shows comb lines on movement — will that carry into the MP4?
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Yes. AVI content is often interlaced, because the format comes from the broadcast and DVD era, and this converter has no deinterlace option, so the combing carries into the MP4. If it matters, deinterlace the AVI first in a desktop tool such as HandBrake or ffmpeg (the yadif filter). AVI is Microsoft’s Audio Video Interleave, introduced in 1992 on top of the RIFF chunk format — one of the oldest containers still in circulation.
My AVI recordings are split into numbered parts — does MP4 have the same limit?
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No, and that is one of the better reasons to move. The AVI container has a practical single-file ceiling that long or high-bitrate recordings run straight into, which is exactly why old captures arrive as part1, part2, part3. MP4 has no equivalent limit, so the pieces can be rejoined into one continuous file. AVI has no native support for modern codecs, variable frame rate, soft subtitles or files over 4 GB without hacks, and its per-chunk overhead bloats the file.
Can I add selectable subtitles once the file is MP4?
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Yes. AVI has no usable soft-subtitle track, so subtitles for AVI content had to be burned into the picture or shipped as a separate sidecar file. MP4 carries subtitles as their own selectable stream, so after conversion you can attach an SRT track the viewer can switch on, switch off or restyle. Almost every MP4 in the wild is H.264 video with AAC audio; the container also legally holds HEVC, AV1 and VP9.
Will the MP4 play on a phone without anything installed?
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That is the whole argument for it. MP4 is what phones record to and what every phone, tablet, console, television and browser built in the last decade decodes in hardware, so a file in it opens on whatever the recipient happens to own. Hardware decoding is the part people underestimate: it is why an hour of video plays on a phone without draining the battery, and why nothing else is a safer choice when you do not know what the file will land on. MP4 is the safest possible delivery target — every phone, browser, console, editor and Smart TV built in the last decade plays it without extra software.
My AVI has several audio tracks — do they all survive into the MP4?
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No. The converter keeps one audio track, the one with the most channels (normally the main mix), and drops the rest; there is no setting to pick a different one. To keep another track, remux the AVI with that track first (VLC or ffmpeg can do this), then convert it. AVI is trivially simple, which is exactly why ancient camcorders, capture cards, DVD ripping tools and Windows-era software all still emit it. MP4 only supports one widely-honoured subtitle format (mov_text), and multi-track audio is unreliable outside desktop players.
Will the MP4 play in a browser when the AVI would not?
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Yes, and that is usually the whole reason for the conversion. An AVI embedded in a web page either shows a broken player or forces a download, because browsers ship no decoder for it. MP4 plays inline through the native HTML5 video element with no plugin and no external application.
Is there a file-size limit when converting AVI to MP4?
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Free conversions have a size limit per file, set by the type of file, and the page tells you when a file is over it. A paid plan removes that limit, so much larger files can be converted.
Can I batch-convert several AVI files to MP4 at once?
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Several files in one job need a paid plan. Free use is one file per conversion, one conversion an hour. On a paid plan you can add several files to one job, then download each result on its own or all of them in one ZIP.
What happens to my AVI files after the conversion?
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Uploaded files are processed on our own conversion servers, nobody looks at them, and they are not shared. The upload and the converted file are both deleted automatically about 24 hours after the conversion, which leaves time to download the result. See /privacy/ for the full policy.
Will my MP4 play on phones, tablets, and TVs?
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Yes — MP4 uses modern codecs that play natively on iOS, Android, Smart TVs, game consoles, and every modern browser.
