Convert MKV to MP4: 5 Methods Compared (Fastest First)

Which method should you pick?

VLC also converts MKV → MP4 (Media → Convert/Save) but it's buried, single-file, and slow — fine for a one-off, not recommended otherwise.

Converting MKV to MP4 in Formatif Pro

With the Video Codec and Audio Codec COPY option, you can remux a batch of MKV videos to MP4 in seconds, or re-encode fully.

FFmpeg remux MKV to MP4 (no re-encoding)

One command copies the video and audio streams untouched into a new MP4 container. Seconds per file, bit-for-bit identical quality. If you don't have FFmpeg yet: Windows — winget install ffmpeg; macOS — brew install ffmpeg; Linux — sudo apt install ffmpeg.

ffmpeg -i input.mkv -c copy output.mp4

for %i in (*.mkv) do ffmpeg -i "%i" -c copy "%~ni.mp4"

Get-ChildItem *.mkv | ForEach-Object { ffmpeg -i $_.FullName -c copy ($_.BaseName + '.mp4') }

for f in *.mkv; do ffmpeg -i "$f" -c copy "${f%.mkv}.mp4"; done

ffmpeg -i input.mkv -c:v copy -c:a aac output.mp4

ffmpeg -i input.mkv -c copy -sn output.mp4

ffmpeg -i input.mkv -c:v libx264 -crf 20 -c:a aac output.mp4

Method 3: OBS built-in remux (free, zero commands)

If the MKV came from OBS, the converter is already installed — OBS MKV to MP4 is a built-in two-step job for both past and future recordings. (Need to split the audio tracks while you are in there? That is a separate OBS multi-track audio workflow.)

1. Open OBS Studio → File → Remux Recordings.
2. Select your MKV file(s), choose the output folder, and start.
3. Done in seconds — same zero-loss stream copy as the FFmpeg command.

And for all future recordings: Settings → Advanced → Recording → check “Automatically remux to MP4.” Record crash-safe MKV, receive MP4 automatically on stop. There is no reason not to enable this.

Method 4: Shutter Encoder rewrap (free GUI, batch queue)

Prefer buttons to terminals? Shutter Encoder (free, Windows/macOS/Linux) exposes remuxing as a one-click function:

1. Drag in one file or a whole folder.
2. Set the Function dropdown to Rewrap → .mp4.
3. Hit Start. Same instant, lossless stream copy — with a progress bar.

Method 5: HandBrake (free GUI, also shrinks files)

HandBrake always re-encodes — minutes instead of seconds — so only reach for it when you also want a smaller file or a different codec:

1. Open the MKV, pick the Fast 1080p30 preset (or HQ 1080p30 for near-invisible loss).
2. Set format to MP4, adjust quality (RF 20–22 is the sweet spot).
3. Add more files to the queue for batch, then Start.

Rule of thumb: straight container swap → remux (methods 2–4). Container swap plus smaller file → HandBrake.

How long does it take to convert MKV to MP4?

A remux takes seconds, because nothing is re-encoded — the limit is your disk speed, not your CPU. A re-encode is compute-bound: roughly real-time on CPU, several times faster on a GPU. Typical figures for a 1-hour 1080p file on a modern SSD:

Estimates for a 1-hour 1080p source on an SSD; re-encode times scale with resolution and encoder. Keep the source and output on the same disk so a remux does not read and write across two devices.

Large files are where remuxing wins outright: a 3-hour film or a 4K HDR recording still copies in under a minute, while re-encoding the same file can run for hours. If you also need to get under a size limit, remux first and compress the MP4 afterward.

Doing this across a whole season or archive keeps the same seconds-per-file math: Formatif Pro remuxes an entire folder in one pass — $8.95 one-time with a 3-day trial — instead of you running the command file by file.

Can Adobe Media Encoder convert MKV to MP4?

Usually yes — current versions import many MKV files, so you can open one and encode straight to MP4 or MOV. Two caveats decide whether it works for your file: import still fails when the container holds a codec Media Encoder can't read, and Media Encoder cannot export MKV at all — the support is import-only.

If a file won't open, don't transcode blind. Remux the MKV to MP4 first — seconds, no quality loss — then import the MP4. The video stream stays untouched and Media Encoder gets a container it handles cleanly.

• MKV imports fine — encode directly to MP4 or MOV.
• Import fails or audio is missing — remux to MP4 with the FFmpeg command above, then re-import.
• Converting a whole camera or OBS archive — batch-remux the folder with FFmpeg or Formatif Pro, then bring the MP4s into Media Encoder in one go.

The same remux-first rule helps with Premiere Pro, After Effects, and other editors that are picky about containers: get the file into a friendly container once, and everything downstream behaves. For the container choice itself, see MKV vs MP4 explained.

MKV to MP4 questions, answered

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