M4V to MKV Converter

M4V vs MKV — Which Should You Convert To?

M4V is Apple's MP4-style container, built for the iTunes era and tied to the Apple ecosystem; MKV (Matroska) is an open container that VLC, MPV, Plex, and Jellyfin all read happily. If you are pulling DRM-free iTunes-era files into an open archival library, or you want to attach external subtitles and chapters, MKV is the better home. One honest caveat first: a DRM-protected iTunes purchase cannot be converted at all (see the FAQ), and if all you need is broader playback, a DRM-free .m4v can often just be renamed .mp4.

Side-by-side Comparison

When to Pick M4V (or just rename it)

• You stay inside the Apple ecosystem — QuickTime, the TV app, iPhone, iPad — where M4V plays without extra software.
• Your file is a DRM-protected iTunes purchase or rental: it must stay M4V, because no converter can decode FairPlay.
• You only need broader compatibility and the file is DRM-free: renaming .m4v to .mp4 is enough, since both use H.264 and AAC and are technically the same MP4 format. The M4V to MP4 converter does this cleanly if you would rather not rename by hand.

When to Pick MKV

• You are building an open, future-proof archive and want a container that open-source players and media servers read everywhere.
• You run a Plex or Jellyfin library and want one file to carry the video, several audio tracks, and chapters.
• You need to attach or keep external subtitle tracks alongside the video in a single file.
• You want a container that is never DRM-locked and is not tied to any one vendor's ecosystem.

Which Video Codec Should the MKV Use?

Because MKV is codec-agnostic, the Video Codec dropdown is a real decision rather than a formality. The source M4V holds H.264, so anything other than H.264 means a bigger change to the picture data:

The audio side is the same shape of choice: AAC is the compact default that matches the source, AC3 keeps a surround mix intact for a home-theatre setup, and FLAC stores the audio losslessly at a much larger size. If you are unsure, leaving both codecs at their defaults produces the file most media servers are happiest with.

How to Convert M4V to MKV

1. Upload Your M4V File: Drag and drop your file onto the page, or click "+ Add Files" to browse. You can queue several DRM-free M4V or MP4 videos and process them with the same settings.
2. Choose Video and Audio Codec: Open Advanced Options. Video Codec defaults to H.264 and Audio Codec to AAC, which match the source and keep the file small; switch Video Codec to H.265 for smaller files, or set Audio Codec to FLAC or AC3 if your library expects it.
3. Set Quality or File Size (Optional): Under File Compression, leave the Quality Preset on Very High, or use Specific file size, Constant Bitrate, or Constant Quality. You can also resize under Video resolution or cut a section with Trim.
4. Convert and Download: Click Convert and download your MKV. No sign-up, no watermark.

Frequently Asked Questions

Can I convert a DRM-protected iTunes M4V to MKV?

No. Movies, TV episodes, and rentals from the iTunes Store are often wrapped in Apple's FairPlay copy protection, which limits playback to devices authorized with the purchasing Apple account. A FairPlay-protected M4V cannot be decoded by any converter, so the job will fail. Only DRM-free M4V files — your own screen recordings, exports, camera footage, or downloads that were never encrypted — can be converted to MKV.

Is this a lossless conversion, or is the video re-encoded?

The video is re-encoded, not copied stream-for-stream. The output container defaults to H.264 video and AAC audio, and the file is decoded and re-encoded into the MKV container rather than remuxed bit-for-bit. Because H.264 and AAC are lossy codecs, a single pass at the default Very High quality keeps the result visually and audibly close to the source for normal viewing. If you only want the broader compatibility of an open file and not a true re-encode, renaming a DRM-free .m4v to .mp4 avoids any quality change at all.

Will the MKV play on my Mac or in QuickTime?

Not in QuickTime — Apple's built-in player does not support the MKV container, and neither do the TV app or the default iOS players. That is expected, not a fault of the file: MKV is an open container Apple never adopted. On a Mac, open the MKV in VLC or MPV, both free, and it plays fine. If you specifically need an Apple-native file, convert to MP4 instead, which QuickTime opens directly.

Does converting to MKV let me keep multiple audio tracks and subtitles?

MKV is the right container for that because Matroska can hold several audio, subtitle, and chapter tracks in a single file. What actually ends up in your output depends on what the source M4V contains — most iTunes-era M4V files carry one H.264 video and one AAC audio track, so a straight conversion produces a single-track MKV. The advantage of MKV is that the container is ready to carry more tracks if you later mux them in, where M4V is not built for that flexibility.

Why convert M4V to MKV instead of just keeping the file as-is?

MKV is an open, vendor-neutral container that VLC, MPV, Plex, Jellyfin, and most media servers read without plugins, which makes it a stronger choice for a long-term or shared library than Apple's M4V. If your only goal is to play a DRM-free file on more devices, you may not need a conversion at all — renaming .m4v to .mp4 works because both are the same underlying MP4 format with H.264 and AAC. Pick MKV when you want the open container, multi-track headroom, and media-server friendliness; pick the rename or MP4 when you just want it to play.

Will the MKV keep my chapter markers?

Matroska is one of the best containers there is for chapters — it stores them as structured entries with names, nested levels, and even per-language titles, which is why media servers display chapter menus for MKV files so reliably. What arrives in your output, though, depends on the conversion rather than on the container's capability: this page produces a fresh encode of the video and audio streams, so treat chapter markers from the source M4V as not carried across. That is easy to correct after the fact, because chapters are metadata rather than part of the picture. MKVToolNix is the free tool most people use for this, with builds for Windows, macOS, and Linux. Its mkvpropedit utility is documented as modifying the properties of an existing Matroska file "without a complete remux," and its --chapters option adds or replaces the chapter list outright — so you can fix chapters in seconds after the conversion, with no second pass over the video.

What is the actual difference between .m4v and .mp4?

Technically, very little — both are the same ISO base media file format, and a DRM-free M4V is an MP4 wearing a different extension. The differences are conventions Apple layered on top. Apple uses .m4v to mark video content in iTunes and the Apple TV app so those apps treat it as a movie or TV episode rather than as a generic file; the extension is also where FairPlay-protected purchases live, which is the one case where the difference genuinely matters, since no converter can decode them. Apple's variant has additionally been used for iTunes movies carrying Dolby Digital surround audio, which is occasionally why a strict player accepts a renamed file's video but not its sound. For an ordinary DRM-free export, renaming .m4v to .mp4 changes nothing about the bytes and is the fastest fix for a player that judges files by extension; M4V to MP4 does the same thing without you touching the filename.

How are my files handled, and how long are they kept?

In our testing, a short DRM-free 1080p M4V re-encoded to MKV at the default Very High quality produced a file within a few percent of the original size, with the picture indistinguishable at normal viewing distance. Your M4V is uploaded over an encrypted connection, processed on our servers, and the files are deleted automatically a few hours after the conversion. There is no sign-up, no watermark, and your files are never shared or made public. The practical limit on a large video is upload size and time, not your device.