Stayput

↑↓ to move, Enter to open, Esc to close. Search runs on this page. Nothing you type is sent.

Convert M4V to MP4

Turn M4V videos into MP4s that play on Windows, Android, TVs and upload forms, without uploading them.

Converts M4V video files to MP4, copying H.264 video and AAC or MP3 sound across unchanged so most files finish in seconds with no quality loss. It is free, and your videos are not uploaded: the conversion runs in your browser tab. The size limit is your device’s memory (phones hold less), and after one visit and a short wait the page works offline.

Drop M4V files to convert to MP4or click to choose files. Batches welcome.
    Details

    H.264 video and AAC sound are copied as they are, so those files convert in seconds with no quality loss. Other formats are re-encoded.

    Working…

    Done

    Your files are processed on this device and never sent to a server. Reload the page to clear everything from memory.

    M4V is Apple’s name for an MP4-style video file. The two share a container design, so the picture and sound inside are often exactly the same; what differs is the extension. Some Windows players, TVs, editors and upload forms only take .mp4, and that is the only reason people convert.

    This page opens each M4V in your browser and writes an MP4. When the video is H.264 and the sound is AAC or MP3, both are copied across without being decoded, so the picture is untouched and a long file takes about as long as it takes to read it from disk. Anything else is re-encoded by your browser’s own encoder, and the result line says which happened.

    For example, a 45-minute episode of 700 MB comes out at about 700 MB: copying changes the wrapper, not the size. If you need it smaller afterwards, send the MP4 through Compress video and pick a size.

    One thing this page cannot do is remove copy protection. Films and shows bought or rented in the iTunes Store carry protection that stops a browser from reading the video, so those files will not convert here. Files you made yourself, or exported from an editor or camera app, convert normally.

    How it works

    1. Drop one or more M4V files, or tap to pick them.
    2. Tick Remove the sound if you want a silent clip.
    3. Convert, then use the MP4 anywhere. Several files download together as a zip.

    In your browser, not on a server

    Mediabunny (MPL-2.0), a media toolkit written in TypeScript, reads the MOV, MKV, WebM or MP4 container in your tab. H.264 video and AAC or MP3 sound are copied into the new MP4 packet by packet, which takes seconds and changes nothing in the picture. Other video (VP8, VP9, AV1) is decoded and re-encoded by your browser’s own video encoder through WebCodecs, H.264 where available, and other sound becomes AAC or Opus. The MP4 is written in memory.

    Compared with upload-based tools: Online converters upload the whole video just to rewrap it, which can take longer than the conversion itself, cap free files at 100 MB to 1 GB, and keep a copy on their server. Here the file never leaves your device, and a large MOV from your phone converts in seconds because nothing is re-encoded that does not need to be.

    Verify it yourself. Give the page a short while after one visit to save itself for offline use, then turn off Wi-Fi or switch to airplane mode and run the tool again. Or open your browser's developer tools (F12, or Cmd-Option-I on a Mac), pick the Network tab, and watch it while you convert. The panel above does the same count for you.

    Questions

    Can I just rename the file from .m4v to .mp4?

    Sometimes, because the container is so close, and a rename is worth a try for a single file. It fails when the file holds something the player cannot read, and a rename never changes the contents. Converting here checks the streams and copies or re-encodes them properly.

    Will it convert a movie I bought in iTunes?

    No. Purchases and rentals from the iTunes Store are copy protected, and a browser cannot read protected video. This page does not remove protection. It converts M4V files without it.

    How do I know whether it re-encoded my video?

    Each result line names the video codec and says either "H.264 copied, no quality loss" or "re-encoded to" a codec. Copied means the picture is untouched.

    There is no sound in the MP4. Why?

    AAC and MP3 sound is copied. Other sound, such as Dolby Digital, is re-encoded only if your browser can decode it, and otherwise the result line says the sound was left out. Chrome, Edge and Safari decode the most formats.

    Are subtitles, chapters and extra audio tracks kept?

    No. Only the main video and the main sound track are written. Extra audio languages and subtitle tracks are left out, so keep the original M4V if you need them.

    Are my videos uploaded?

    No. Each M4V is read from your disk and the MP4 is written back to your disk by code running in this tab, so a home video never reaches a server.

    More video and audio tools

    Video to MP4

    Turn MOV, MKV and WebM files into MP4s that play everywhere. Converted on this device, never uploaded.

    Change video speed

    Make a video faster or slower, with sound that stays at the right pitch. Done on this device, never uploaded.

    Merge videos

    Combine clips into a single video, in the order you choose. Done on this device, never uploaded.

    Add audio to video

    Put music or a voice-over on a video, or replace its sound. The picture is copied as it is, and nothing is uploaded.

    Other conversions

    Guides