1Upload every file you want combined — at least two of them.
2Drag the uploaded items into the order you want; the order is taken from the list, not from the filenames.
3Start the merge, which joins matching inputs without re-encoding them and reconciles mismatched ones exactly once.
4Download the single combined Video file.
Merge Video 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 Video join the files together?
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Concretely, matching clips are concatenated without re-encoding and mismatched ones are normalised to a common format first, so you get the fast path whenever the sources permit it. Upload everything you want combined and the result comes back as a single file.
Anything specific to Video when merging?
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Yes — the container and codec are probed before anything runs, so mixed uploads in one batch are handled per file. That is worth checking when the inputs did not all come from the same source.
How many files can I combine at once?
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On the free tier a merge accepts two files at a time, which is deliberately higher than the single-file limit on other tools because merging one file is meaningless. A pass removes the cap entirely.
Which video formats does Merge Video accept?
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MP4, MOV, MKV, WebM, AVI, WMV, FLV, 3GP, M4V, MPEG and MPG. Each file is probed for its real container and codec before anything runs, so a mixed batch is handled correctly file by file.
Is there a file size limit on Merge Video?
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Yes: free accounts process video up to 1 GiB per file whichever container you brought; ffmpeg with x264, x265 and libvpx does the encoding. It is high enough that upload speed is usually the binding constraint rather than the cap itself.
Will Merge Video lower the quality of my videos?
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Only if the operation requires re-drawing frames. Container-level and timeline-level work is done as a stream copy, which is bit-identical to the source and finishes in seconds. Anything that must re-encode does so at a quality level you choose.
Can I run Merge Video on several videos at once?
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Yes, and it matters here more than anywhere else — video jobs run in minutes, so queueing the batch in parallel is the difference between one wait and several.
Why does a EPUB site host Merge Video?
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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 Video 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 Video 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 Video means the conversion is made from the version you settled on, not from the one you were still fixing.
Is Merge Video 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, and nothing is kept: uploads are deleted from the workers shortly after the job finishes, nothing is read and nothing is indexed. Free accounts exist for history and batch size, not for access.
