People type mp4 trimmer when the file already ends in .mp4 and they want a shorter mp4, not a lesson on every container on earth. Phone clips. Screen recordings. Camera cards that already wrote mp4. This page is that box: open the file, cut time, keep mp4 if that is what the player needs. A generic start/end walk with no container talk sits on Trim video. Cutting a middle ad or splitting into several files sits on Video cutter. Picture edges sit on Video cropper.

This is LosslessCut. Mikael Finstad (mifi) publishes it under GPL-2.0. We did not make it. Official files live on GitHub Releases. The repo is mifi/lossless-cut. This site does not host the file. Skip Softonic, CNET, and unofficial sites that wrap the name. There is no winget command. The author does not maintain one.

The button on this page goes to Install on the home page. Home is Open Source Video Trimmer. Releases on home is the live file list and the copy box. Trust notes sit on Video Trimmer Download Safe.

Get the Windows 7z so an mp4 trimmer can run

Copy the filename from the box. It is the same name as home:

LosslessCut-win-x64.7z
Copy

Open the latest GitHub release. Pick that 7z. Skip APPX. The author labels APPX as a file you should not use. Extract with 7-Zip into a folder you control. Run LosslessCut.exe. There is no installer. Arm64 Windows has its own 7z on the same release page if that is your machine. macOS takes a dmg. Linux takes tar.bz2 or AppImage. This page stays on the Windows mp4 path most people mean.

More of the live file list sits on Open Source Video Trimmer Releases. LICENSE and the repo sit on Open Source Video Trimmer GitHub. Latest live tag observed on this site is V3.69.0. Take the newest they published unless you have a reason to pin.

How to use an mp4 trimmer on this PC

  1. Open GitHub Releases, take LosslessCut-win-x64.7z, extract with 7-Zip, and run LosslessCut.exe.
  2. Open the mp4 you already have. Drag it into the player, or press Ctrl+O. Wait until the preview and timeline load. If the player looks blank, try FFmpeg-assisted playback from the File menu. The cut still runs on the original file.
  3. Seek to the new start. Press I. Seek to the new end. Press O. Play that window once so you know the keep range is right.
  4. Set the output format to mp4 if the export should stay an mp4. That is remux: same tracks, different box, when the source was something else. If the source is already mp4 and you leave the format alone, the export stays in that family.
  5. Press Export (or E), check the overview, then confirm. The original file is not modified. A new file lands next to the source, or in the working directory you set.

That list is the mp4 trimmer path. You are not uploading the clip. You are not opening a website encoder. The bytes stay on this PC.

Mp4 is the box, the codec sits inside

An mp4 trimmer works on a container, not on a magic codec named mp4. Mp4 is the box. Inside it you usually find a video track (often H264, sometimes H265) and an audio track (often AAC). The file name can say .mp4 while the real box is MOV. LosslessCut reads the file, not the extension. If you rename a mkv to .mp4, the player and this app still see Matroska.

Remux means pour the same tracks into a different box. H264 plus AAC inside mkv can often become H264 plus AAC inside mp4 without encoding the picture again. That is the usual reason to pick mp4 on export: a phone, a TV, or an editor that opens mp4 and shrugs at mkv. Matroska holds more kinds of tracks. Mp4 is pickier. If a subtitle or an odd audio codec will not fit in mp4, the export can fail or drop that track. Then either keep mkv, or drop the extra track in the Tracks panel and export mp4 again.

LosslessCut has a short primer on this: format versus codec. Changing the output format is remux. Cutting time is a copy of packets. Neither step is a quality slider. If you wanted a smaller file by crushing the picture, that is a different program (HandBrake is the one the docs name). An mp4 trimmer here makes a shorter mp4, or an mp4 from a compatible source, by throwing away time or by changing the box.

Why people ask for an mp4 trimmer

iPhone and QuickTime like mp4 and MOV. They do not like mkv. A GoPro or a phone already wrote mp4, so the job is only to cut the take. A TV capture might be TS. Cutting that and remuxing to mp4 is a documented lossless use: drop the ads, land an mp4. A desktop mkv from OBS can be remuxed to mp4 after you trim, if the tracks fit.

VP8 and VP9 in a webm often will not sit in mp4. If the source is webm, do not force mp4 and then wonder why export errors. Keep webm, or transcode in another tool. This page will not pretend every file becomes a happy mp4. The honest mp4 trimmer path is: mp4 in, shorter mp4 out, or a compatible remux into mp4.

Output file names include from/to times by default. That is useful when you cut three takes from one camera card. Do not export over the source. The app refuses in-place replace on purpose. Pick a folder you control. Play the new mp4 in the player you actually use (VLC, the phone, the editor) before you delete the long original.

Skip APPX, skip wrappers, keep GitHub

The Windows storefront file on GitHub is APPX. Skip it. The author says it does not work. The working Windows fetch is the 7z. Extract. Run the exe. A video trimmer free download in this sense is that 7z on GitHub Releases, GPL-2.0, no storefront unlock. Softonic and CNET wrap the name. You do not need them.

If a page offers losslesscut.exe as a direct installer from a blog, walk away. The release assets look like LosslessCut-win-x64.7z. Copy that name from the box on home if you want a check. Fetch notes sit on Video Trimmer Download Safe.

Tracks, chapters, and what stays in the mp4

Most mp4 files have one video track and one audio track. Both get cut together. If you only wanted the picture, disable the audio track before export. If you only wanted the sound, disable the video track. The Tracks panel is the list. Advanced view (baby icon) shows more of that UI if a control is hiding.

Chapters inside an mp4 can be used as cut points. If the file already has chapter marks, you can cut by chapter instead of hunting with I and O. That is handy on a downloaded talk that shipped chapters. CSV import exists if another tool already wrote the times. This page still exports an mp4 when you set that format. It does not become a timeline editor with titles and fades. Fades would re-encode. An mp4 trimmer here copies.

Rotation metadata is a flag, not a crop. If the phone stored the clip on its side, the rotation button can write the flag so players stand it up. That is not the same as Video cropper, which changes the picture rectangle. Keep those jobs apart.

How do I use an mp4 trimmer?

Install from GitHub Releases with LosslessCut-win-x64.7z. Skip APPX. Extract with 7-Zip. Run LosslessCut.exe. Open the mp4. Press I and O for the keep range. Set output to mp4 if you need that container. Export. The original stays. Details are in the numbered list on this page. The install pointer is Install on the home page.

Is mp4 the codec or the file type?

Mp4 is the container, the box. The codec is the recipe inside, usually H264 or H265 for video and AAC for sound. An mp4 trimmer copies those tracks and can remux them into an mp4 box. It does not rename the codec. If a player needs mp4, you change the box. If a player needs a smaller picture, you need a different tool that re-encodes.

Will an mp4 trimmer work on my iPhone file?

Often yes, because phones already write mp4 or MOV, and this app treats those as first-class. Open the file on the PC, cut, export mp4. Copy the new file back to the phone if that is where you watch it. App Store vs GitHub builds differ on some sandbox rules. This site points at GitHub Releases, not a store listing.

Did you make this mp4 trimmer?

No. Mikael Finstad publishes LosslessCut under GPL-2.0. Official files live on GitHub Releases. This site only points at that page. We do not host the 7z.

Related jobs: Video cropper, Video cutter, Trim video, Video Trimmer Download Safe. File host: GitHub Releases. Install button on the home page.