1Upload the FLV videos you want resized — work from the largest original you have rather than from a copy you already shrank once.
2Set the new size: for an image, a width and height in pixels with an optional aspect-ratio lock; for a video, one of the preset sizes from 1920x1080 down to 640x360.
3Start the resize; the picture is scaled to the size you chose.
4Download the resized FLV file.
Resize FLV FAQ
Is there anything specific to FLV I should watch for?
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Yes — nothing plays FLV natively any more, so the practical end of any FLV job is a modern container. Worth checking before you resize a file you will not be able to regenerate.
What dimensions should I actually target?
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Match the slot it will live in. A full-width web hero rarely needs more than 1920 pixels wide, a content image 1200, a thumbnail 400, and doubling those numbers covers high-DPI screens. Anything beyond that is bytes nobody sees.
Can I keep the aspect ratio, or force exact dimensions?
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Both. Lock the ratio and one dimension is derived from the other, which is what you want almost always. Unlock it and you get exactly the numbers you typed, at the cost of stretching — useful for a fixed slot, wrong for a photograph.
Does Resize FLV cost anything?
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No. Resize FLV is free without an account, and the output has no watermark, corner logo or intro card. The upload and the result are deleted automatically about 24 hours after the job, which leaves time to download the result.
What can I upload to Resize FLV?
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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 Resize FLV?
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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.
Why does a MP3 site host Resize FLV?
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MP3.to is built around the format that made portable audio ordinary: universally playable, small enough to ignore, and lossy in a way that only matters if you keep re-encoding it. Audio jobs cluster: the same person who needs a format changed usually needs the file cut, levelled or made smaller in the same sitting. Putting Resize FLV behind the same upload, the same caps and the same account is what turns three tabs into one.
What should I do with the result once Resize FLV is finished?
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The converter on this site moves audio between MP3, WAV, FLAC, M4A, OGG and Opus, so the output format is a decision you can leave until the end rather than commit to at the start. Doing that after Resize FLV rather than before means the encode happens once, on the file you actually settled on, instead of twice.
Is Resize FLV here the same tool the sibling sites run?
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The engines are shared — the same ffmpeg build, the same workers, the same limits. What a MP3 site adds is a point of view about bitrates, about what survives an encode and about when a lossless intermediate is worth the upload time. It also starts from one fact about the format this site is named after: MP3 frames are fixed-size blocks, so a cut lands on a frame boundary and gapless playback markers do not survive a re-encode.
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.
