1Upload every file you want combined — at least two of them.
2Add the files in the order you want them joined; the first file you add comes first.
3Start the merge; the files are joined one after another into a single file.
4Download the single combined AVI file.
Merge AVI FAQ
Is the merge lossless?
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It is whenever the inputs already agree — the encoded data is copied straight through. It stops being lossless only when the inputs disagree and something has to be re-encoded to make them compatible, and even then it is one pass, not one per file.
How does Merge AVI join the files together?
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Concretely, clips with matching codec, resolution and frame rate are concatenated as a stream copy and the join is instant; anything mismatched is normalised to a common format first, which is the slow path but the only correct one. Upload everything you want combined and the result comes back as a single file.
Anything specific to AVI when merging?
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Yes — AVI has no modern index or B-frame-friendly structure, so accurate seeking usually requires a real re-encode rather than a copy. That is worth checking when the inputs did not all come from the same source.
What can I upload to Merge AVI?
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MP4, MOV, MKV, WebM, AVI, WMV, FLV, 3GP, M4V, MPEG and MPG. The container and codec are probed before anything runs, so a mixed batch is handled correctly per file rather than assumed to be uniform.
Is there a file size limit on Merge AVI?
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Yes: free accounts process video up to 40 MB per file, by far the most generous cap on the site; ffmpeg with x264, x265 and libvpx does the work, which is the same toolchain behind most desktop video software. Video is the one family where the cap is high enough that upload time, not the limit, is what you will actually notice.
Can I run Merge AVI on several AVI videos at once?
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Yes. Uploads queue in parallel, which matters more here than anywhere else because video jobs are minutes rather than seconds. Free accounts run one file at a time; a pass lifts that.
Why does a EPUB site host Merge AVI?
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EPUB.to is built around the open eBook format — XHTML in a zip, reflowable by design, and readable on hardware nobody has thought about the layout for. A book is a zip full of markup, images and fonts, so almost every job people bring to an eBook site is really a job on one of those things. Merge AVI runs on the same upload and the same account as the conversions because that is where it is needed.
What should I do with the result once Merge AVI is finished?
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The converter on this site moves books between EPUB, MOBI, AZW3, PDF and DOCX, so a title ends up on whatever hardware is actually going to read it. Doing that after Merge AVI means the conversion is made from the version you settled on, not from the one you were still fixing.
Is Merge AVI here the same tool the sibling sites run?
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The engines are shared — the same toolchain, the same workers, the same limits. What a EPUB site adds is a view on reflow: which of these operations a reflowable book genuinely supports, and which ones only make sense on the fixed-layout media inside it. It also starts from one fact about the format this site is named after: the book is a zip of XHTML with a manifest, so the text costs almost nothing and every decision that matters is about the embedded images and font subsets.
Do I need an account, and does anything get kept?
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No account is needed. Uploads and results are kept for about 24 hours, which leaves time to download the result, and are then deleted automatically; nobody reads, lists or indexes them. Several files in one job need a paid plan.
