HermitFile Pro

Swap a green screen for a solid colour

Classic chroma key, not an AI guess — pick the key colour, pick what replaces it, tune the edge, and this decodes each frame, keys it and re-encodes an MP4, on this device. The original audio comes along unchanged if it's AAC.

Drop a video hereTap anywhere in this box
MP4, MOV, MKV, WebM — anything your browser can read. Any length: there is no upload, so there is no limit.

Nothing is uploaded. Open your browser’s Network tab while you convert — you will see the file go nowhere.

Key settings

Preview updates live as you adjust these — tune it before converting the whole clip.

What you'll get back

Worked out from this actual file and this actual browser, before anything is written.

Range and size

Your video

This is chroma key, not AI

Every pixel is compared to the key colour by hue, saturation and brightness, and the ones close enough become the replacement colour — the same math video software has used for decades, running entirely in this page. It needs a real green or blue screen behind the subject; it has no idea where a person is in an ordinary room, and it will not pretend to. That trade is deliberate: the AI version of this tool needs a model and a server bill neither of which HermitFile has to pass on to you, which is why this one is free to run — one file at a time, any size, forever, and no account. Pro only changes how many clips go through it in a single pass.

Tuning the edge: tolerance and spill

Tolerance controls how far a pixel's colour can drift from the key colour and still count as background — low keeps only a near-perfect match, high catches more of an unevenly lit screen but risks eating into the subject too. Watch hair and fabric edges in the preview: a thin green or blue tinge there is called spill, and this tool pulls it out automatically near the cutoff without touching colours that are nowhere near the key.

Why the audio sometimes doesn't survive

The video is genuinely re-encoded, because keying a frame means changing its pixels — there is no wrapper trick for that. Audio doesn't need to be, so it is copied across as compressed packets exactly like the site's other video tools do, provided it's AAC. Anything else would need a decoder and an encoder this tool doesn't carry, so it's dropped rather than silently guessed at, and the plan says so before you convert anything.

Nothing is uploaded

Decoding, keying and video encoding all happen in this page. There is no server here to send the video to, and the page's security policy blocks any connection to anywhere but this site. Here is how that is enforced.

How to swap a green screen

  1. Drop the video in. Nothing is sent anywhere — the whole file stays on this device.
  2. Pick the key colour and a replacement, and adjust tolerance until the live preview looks clean.
  3. Set the range, frame rate and size, then press Convert and download.

All 39 HermitFile tools

Every one of them runs in your browser. Nothing you open is uploaded, and nothing is stored.

Show all tools

Image tools

Make a passport photoFinds the face and frames it to a passport specification, then saves at the exact pixel size and under the KB limit. Check my passport photoCheck a passport or visa photo against the rules the authority actually publishes, before you submit it. Check my document uploadCheck a document against a portal’s published format list and size ceiling, before it is silently rejected. Resize to an exact KBHit a pixel size and a KB limit at the same time, without the picture being shrunk behind your back. Crop & rotateCut an exact rectangle by dragging or by typing the numbers. Rotate, flip, and never enlarge. iPhone HEIC to JPGConvert iPhone photos into a format every upload form accepts. Convert formatWebP, AVIF, PNG, JPG and more. Transparency gets the colour you choose instead of turning black. Compress an imageMake the file smaller while the picture stays exactly the same width and height. Clean a fileSee what a file says about you, then remove it — including text under a redaction box. View & remove EXIFSee the camera, timestamp and GPS coordinates hidden in a photo, then save a clean copy. QR code generator & readerEncodes exactly the link you type, with no redirect through anyone else’s domain. Reads codes from an image too. Read text from a scanPull selectable text out of a scanned PDF or a photo of a page, without the scan leaving your device.

Video tools

MOV to MP4Turn an iPhone .mov into an .mp4 by swapping the wrapper, with the video copied across and nothing re-encoded. Trim a videoKeep the part you want. The clip is copied rather than re-encoded, so no quality is lost. Split into partsCut a long recording into pieces short enough to post, without re-encoding any of them. Rotate a videoChange the rotation flag a phone wrote instead of re-encoding the picture. Seconds, not minutes. Remove the soundDrop the audio track and copy every frame across untouched — same quality, same size. Video to MP3Convert a video’s sound to MP3, or lift the original audio out byte for byte with nothing re-encoded. Video to GIFPick a range, a frame rate and a size, and get an animated GIF back with nothing uploaded. Green screen swapSwap a green or blue screen for a solid colour with a live preview, no AI model and no watermark. Silence removerFinds the quiet stretches by listening to the audio and cuts them out, with a timeline showing every cut first. Blur pad to a new ratioFit a video into 9:16, 1:1 or another shape with a blurred background instead of black bars. Compress a videoAim at a Discord, email or WhatsApp limit — or your own — and get an MP4 checked afterwards, not just promised. Noise removerLearns your recording’s own background hiss or hum from a quiet stretch, then subtracts exactly that. Auto-reframeCrops a landscape clip to a new shape and pans the crop to follow the motion, instead of a fixed centre. CaptionsBurns an .srt or .vtt subtitle file into the video as styled, timed on-screen text. Beat syncFinds the beats in the clip's own audio and lands a flash or a zoom-punch on each one. Highlight finderScores a clip by loudness and movement, and ranks the best stretches to cut out, losslessly.

PDF tools

Merge PDFsJoin several PDFs into one, in the order you choose, and rotate pages losslessly. Split PDFPull out a page range, or break a document into one file per page. Compress a PDFShrink the pictures inside the file and leave the text selectable. Refuses to hand back a bigger file. PDF to imagesRender each page to a JPG or PNG at the resolution you choose. PDF to textPull the words out of a PDF and copy them or save a .txt file. Says so when a PDF is a scan. Remove a PDF passwordSave a copy that opens with no password, using the password you already know. Rotate PDF pagesTurn some pages or all of them, permanently, with no loss of quality. Remove PDF pagesName the pages you want gone and get everything else back as one document. Redact a PDFSearch every page for a name or a number, remove the text itself, then check the finished file. Images to PDFCombine photos into one PDF that lands under the KB limit the portal demands. Bank statement to CSVEvery transaction out of a statement PDF as a spreadsheet, and it checks its own total against the closing balance.