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.
Will the AVI play smoothly on modern devices after converting to MP4?
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Yes. Legacy AVI files often fail to play in modern browsers and on iOS / Android. MP4 uses widely supported codecs that play natively on phones, tablets, smart TVs, and every modern browser.
Will the converted MP4 be a different size than the AVI?
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Modern codecs compress better, so MP4 from a legacy AVI is typically 30-60% smaller at equivalent quality. Conversions in the opposite direction can grow the file.
My AVI footage shows comb lines on movement — will that carry into the MP4?
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It will unless you deinterlace, and AVI content very often is interlaced because the format comes from the broadcast and DVD era. Interlaced frames store two half-height fields captured a fiftieth of a second apart; on a progressive-scan phone or monitor that reads as horizontal combing on anything that moves. Turn on the deinterlace option and the encoder weaves the fields into whole progressive frames before writing the MP4. 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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Not dependably. AVI stores multiple audio streams as first-class tracks, but MP4 playback support past the first track is inconsistent, so most players will only ever expose one. Choose the track you actually want before converting; the others are better extracted to their own files than left in a container that hides them. 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.
These AVI files came off an old camcorder — is anything special needed?
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Two things, both worth setting before you start. Tape-era cameras recorded interlaced fields and at a frame rate tied to the mains frequency where the camera was sold, so leaving deinterlacing off bakes comb lines into the MP4 permanently, and letting the converter guess the rate can introduce a subtle judder on panning shots. Set both explicitly and the transfer is otherwise clean — the picture is what the tape held, which is the ceiling regardless of what it is converted into.
Is there a file-size limit when converting AVI to MP4?
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Anonymous uploads are capped at a generous default; signed-in free accounts get a higher cap, and Pro accounts have no per-file limit. Browser memory is usually the practical constraint long before our server-side limits kick in.
Can I batch-convert several AVI files to MP4 at once?
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Yes. Drop or pick multiple AVI files in one upload — the converter processes them in parallel and returns a ZIP of the MP4 results. There is no need to repeat the upload step per file.
