Step 1: Provide your AVI files using the button above or by toss and let go.
Step 2: Click the 'Convert' button to start the conversion.
Step 3: Fetch your converted MP4 files.
AVI to MP4 Conversion FAQ
How do I convert AVI to MP4 without re-encoding the video stream?
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There is no stream-copy switch on this page. A few pairs copy a compatible video stream into the MP4 container without re-encoding it, MKV to MP4 among them, which is quick and loses no quality. Most pairs re-encode the video. AVI files predate modern codecs: expect MPEG-4 Part 2 (DivX/Xvid), Motion JPEG or raw uncompressed frames rather than H.264. Almost every MP4 in the wild is H.264 video with AAC audio; the container also legally holds HEVC, AV1 and VP9.
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.
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. 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.
Is it worth converting old AVI recordings to MP4 at all?
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For anything you intend to keep, yes. AVI belongs to an earlier generation of video tooling and the software that reads it is steadily disappearing from phones, browsers and operating systems. Moving the footage to MP4 now, while a clean decoder still exists, is the difference between an archive you can open in ten years and one you cannot.
Will multi-track audio survive AVI to MP4 conversion?
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Usually not. Most conversions keep one audio track, the one with the most channels (normally the main mix), re-encoded for the MP4 container, so commentary and alternate-language tracks are dropped. AVI, WMV, MPEG, FLV, VOB and M4V to MKV keep every track, and so does MP4 to MOV. To keep a different track, remux the AVI with that track first (VLC or ffmpeg can do this), then convert it. MP4 is ISO/IEC 14496-14, standardised in 2001 and derived from the same QuickTime box layout MOV uses.
Are subtitle tracks preserved when converting AVI to MP4?
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On some pairs. MP4 to MOV keeps every text subtitle track. AVI, WMV, MPEG, FLV, VOB and M4V to MKV keep every subtitle track: text subtitles are copied or converted to SRT, and picture-based subtitles such as DVD or Blu-ray ones are copied as they are. MP4, MOV and WebM to MKV keep only the first subtitle track (as ASS), and MP4 to WebM keeps the first one as WebVTT. Other pairs, including MKV to MP4 or MOV and WebM to MP4, drop subtitle tracks, and the converter does not burn them into the picture. Subtitles that are already burned in stay, because they are part of the video frames.
What about MKV attachments (fonts, cover art) when going AVI to MP4?
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MKV is the only mainstream container that stores arbitrary attached files (TTF fonts for ASS subs, JPG cover art, fan-translated PDF inserts). Going from AVI to MP4 drops these attachments when MP4 is not MKV — the elementary streams convert, but the attached payload stays in the source. Keep AVI as a backup if you depend on attached fonts.
Which codec does the MP4 output use by default?
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It depends on the MP4 container. MP4, MOV and MKV output use H.264, which plays on practically every phone, browser and TV. WebM output uses VP9. AVI, WMV and MPEG output use the older codecs those formats were designed for.
