Why didn't my video get much smaller?

If the source was already efficiently encoded at a similar quality, re-encoding can't remove much more without visible damage. Try the Smallest setting or the 720p cap — or accept that the file is already about as small as its content allows. The size numbers shown are always the truth.

Are my files uploaded?

No. The first time you use an audio/video tool, your browser downloads the open-source FFmpeg engine — a 32 MB file, roughly 10 MB once your connection compresses it — as a static file, and that is the only network traffic. Your media files are then processed entirely on your device and never reach a Filesvo server.

Why is processing slower than a desktop app?

The FFmpeg engine runs inside your browser's WebAssembly sandbox on a single thread, which is several times slower than a native install. Short clips finish quickly; re-encoding long videos can take minutes. The progress bar shows the honest state, and you can cancel at any time.

Does this work on phones?

Yes on recent devices, with limits: the engine is a 32 MB file (roughly 10 MB compressed in transit), and phones have less memory available to the browser, so large videos can fail on mobile. If a file fails on your phone, try a smaller file or a desktop browser. The 100 MB per-file limit applies everywhere.

Compress Video Online

Make a video small enough to email, message or upload. Your video is re-encoded to H.264 at the quality level you pick, optionally capped at 720p for extra savings — and the exact before/after sizes are shown, including the honest case where a video was already too efficient to shrink much.

or drag and drop a .mp4 / .m4v / .mov / .webm file here — up to 100 MB

This tool runs the open-source FFmpeg engine in your browser. First use downloads it once (a 32 MB file, roughly 10 MB compressed in transit); after that it loads from your browser cache. Your files are never uploaded. The engine is ffmpeg.wasm, distributed unmodified under the GPL-2.0-or-later.

Processed on your device — files are never uploaded to Filesvo.

How to use Filesvo

Select or drop an MP4, MOV or WebM video (up to 100 MB).
Choose a quality level, and optionally limit resolution to 720p.
Click Compress Video and compare the honest before/after sizes.

How video compression works

Video size is controlled by the encoder's quality setting (CRF): higher CRF numbers discard more detail and produce smaller files. The Balanced setting (CRF 28) typically halves the size of phone footage with little visible change; Smallest (CRF 33) shrinks harder with visible softening.

Resolution is the other lever — a 4K or 1080p video capped to 720p keeps far fewer pixels and compresses much further. If your source was already heavily compressed (screen recordings, downloads), there may be little left to save, and the result card will say so plainly rather than overwrite reality.

The FFmpeg command this runs

This tool is FFmpeg itself, compiled to WebAssembly and running in your browser. Below is the command it builds with the options set as they arrive — generated from the same code that performs the conversion, not written out by hand, so it cannot drift out of date. Paste it into a terminal with FFmpeg installed and it does the same job there.

ffmpeg -y -i input.mp4 -vf "scale=trunc(iw/2)*2:trunc(ih/2)*2" -c:v libx264 -preset veryfast -crf 28 -pix_fmt yuv420p -c:a aac -b:a 128k -movflags +faststart output.mp4

What each option on the tool changes in that command:

Quality

High quality — least savings — -crf 23

Balanced — recommended — -crf 28

Smallest file — visible quality loss — -crf 33

Resolution

Keep original resolution — -vf "scale=trunc(iw/2)*2:trunc(ih/2)*2"

Limit to 720p — saves more — -vf "scale=-2:2*trunc(min(720\,ih)/2)"

The input and output names are placeholders. Your own filenames are used inside the browser, and neither file leaves your device.

Private by design

Your files are processed directly in your browser using the open-source FFmpeg engine compiled to WebAssembly and are not uploaded to Filesvo. Nothing is stored on our servers, because nothing ever reaches them.

The engine is a static file your browser downloads once and then caches — the only network request this tool makes. It is used exactly as its authors published it; see the engines and their licences.

Frequently asked questions

Why didn't my video get much smaller?: If the source was already efficiently encoded at a similar quality, re-encoding can't remove much more without visible damage. Try the Smallest setting or the 720p cap — or accept that the file is already about as small as its content allows. The size numbers shown are always the truth.
Are my files uploaded?: No. The first time you use an audio/video tool, your browser downloads the open-source FFmpeg engine — a 32 MB file, roughly 10 MB once your connection compresses it — as a static file, and that is the only network traffic. Your media files are then processed entirely on your device and never reach a Filesvo server.
Why is processing slower than a desktop app?: The FFmpeg engine runs inside your browser's WebAssembly sandbox on a single thread, which is several times slower than a native install. Short clips finish quickly; re-encoding long videos can take minutes. The progress bar shows the honest state, and you can cancel at any time.
Does this work on phones?: Yes on recent devices, with limits: the engine is a 32 MB file (roughly 10 MB compressed in transit), and phones have less memory available to the browser, so large videos can fail on mobile. If a file fails on your phone, try a smaller file or a desktop browser. The 100 MB per-file limit applies everywhere.

Compress Audio

Shrink MP3, WAV, M4A, OGG and FLAC files to a bitrate you choose, with honest before/after sizes.

Video Trimmer

Cut a clip out of a video with a live preview — frame-exact re-encode or instant lossless keyframe copy.

MOV to MP4

Convert QuickTime MOV videos — including iPhone recordings — into MP4 files that play everywhere.