2Choose the axis — horizontal gives you a mirror image, vertical an upside-down reflection.
3Apply the flip, then check any text, logos or numbers in the preview, because those mirror along with everything else.
4Download the flipped MP4 file.
Flip MP4 FAQ
How does Flip MP4 mirror the file?
+
Concretely, a horizontal or vertical flip is applied as a filter, which needs a re-encode because the coded frames themselves change; the audio stream is copied through untouched. You choose the axis — horizontal produces a mirror image, vertical produces an upside-down reflection — and the whole file is transformed on it.
What is the difference between flipping and rotating?
+
A flip reverses the content across an axis and produces a mirror image; a rotation turns it without reversing anything. Text is the giveaway: it reads backwards after a flip and stays readable after a rotation.
Does the source format matter when flipping?
+
It does. MP4 is the safest delivery container: H.264 video with AAC audio plays on effectively every phone, browser and TV without a codec pack. That is what decides whether the mirror can be done by rewriting the file or requires decoding it first.
Anything specific to MP4 to be aware of?
+
Yes — MP4 keeps its index in a moov atom, so a stream-copy edit is near-instant and the result still seeks properly in a browser. Worth a moment before you flip something you cannot easily recreate.
When would I actually want to flip rather than rotate?
+
Correcting a scan or a webcam capture that came out mirrored, making a symmetrical pair from a single asset, or matching the direction a subject faces to a layout. If the content contains text, logos or numbers, check the result — those mirror too.
Can I flip several files at once?
+
Yes. The same axis is applied to every file in the batch, which is how you fix a whole folder of mirrored captures in one pass instead of one at a time.
What can I upload to Flip MP4?
+
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 Flip MP4?
+
Yes: free accounts process video up to 1 GiB 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.
Will Flip MP4 lower the quality of my MP4 videos?
+
It depends on whether the job needs a re-encode. Operations that only touch the container or the timeline are done as a stream copy and the picture is bit-identical to the source. Anything that has to redraw frames goes through x264/x265 at a quality level you set, where CRF 23 is visually transparent on most footage.
Can I run Flip MP4 on several MP4 videos at once?
+
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.
What happens to audio, subtitle and chapter tracks?
+
They are carried across. Multi-track audio, embedded subtitle tracks and chapter markers survive wherever the target container can represent them — that is the main thing that separates a proper job from a naive re-encode that silently keeps only track one.
Does Flip MP4 cost anything?
+
No. Flip MP4 is free without an account, and the output carries no watermark, no corner logo and no intro card. Uploaded video is deleted from the workers shortly after the job completes.
