Skip to content

Convert MKV to MP4 on Windows: 3 Methods

Convert MKV to MP4 on Windows with GetCompress or FFmpeg. Remux when codecs fit, or re-encode H.264 for Clipchamp, Teams, and uploads.

By Petr Samokhin

Screen capture tools, stream archives, and some editors save MKV. Clipchamp, Photos, and many Windows upload forms expect MP4. Teams rejects the attachment, or a CMS import list shows only MP4. Convert locally so internal demos never go through a random upload site.

Why MKV is awkward on Windows

MKV can hold H.264, HEVC, VP9, multiple audio tracks, and subtitles. Built-in Windows apps prefer MP4.

SourceTypical issue
OBS or capture softwareCrash-safe MKV during recording; sharing wants MP4
Downloaded archiveClipchamp and Photos often refuse import
Editor shareRecipient cannot preview without converting
ScenarioTry firstIf that fails
OBS MKV after recordingRemux with -c copyRe-encode to H.264
HEVC inside MKVRemux if Clipchamp plays itRe-encode for older portals
Need a smaller attachmentTrim, then 720p re-encodeTarget file size in GetCompress

If your source is MOV, see MOV to MP4 on Windows . For size after conversion, see how to compress video on Windows .

Method 1: GetCompress

Best for: Capture folders, preview and trim, and portals that also list a megabyte cap.

GetCompress main window with videos queued and video settings open, including quality, target size, resolution, and format options
  1. Drop one MKV or a whole folder into GetCompress .
  2. Choose MP4 output.
  3. Trim to the seconds you need in the preview.
  4. Set a quality level (Original, High, Medium, Balanced, or Low) or resolution, or type a target file size when the form states a limit.
  5. Export and confirm playback in Clipchamp or your target app before you delete the MKV.

Processing stays on your PC. Save a preset such as “1080p H.264 share” for the next time you convert similar OBS files.

Method 2: Remux with FFmpeg

Best for: Instant container swaps when video and audio already fit MP4.

winget install --id Gyan.FFmpeg -e
ffmpeg -i input.mkv -c copy output.mp4

Batch remux:

mkdir mp4-out
Get-ChildItem *.mkv | ForEach-Object {
 ffmpeg -i $_.Name -c copy "mp4-out\$($_.BaseName).mp4"
}

If video plays but audio is missing, the audio codec likely needs re-encoding with -c:a aac. Sometimes only a subtitle track blocks copy; map video and audio with -map 0:v -map 0:a and skip subtitles.

Limitation: Remux fails when codecs inside MKV are not MP4-compatible. VLC can convert too (Media → Convert / Save), but profiles are easy to mis-pick.

Method 3: Re-encode when remux fails

Best for: HEVC or VP9 inside MKV that must become H.264 for an upload target.

ffmpeg -i input.mkv -c:v libx264 -crf 22 -preset medium `
 -c:a aac -b:a 128k -movflags +faststart output.mp4

Lower resolution for sharing:

ffmpeg -i input.mkv -vf scale=-2:1080 -c:v libx264 -crf 23 `
 -c:a aac -b:a 128k -movflags +faststart output-1080p.mp4
DestinationPractical settings
Teams or Jira720p, CRF 23, AAC 128k
Client OneDrive review1080p, CRF 22, +faststart
Web CMS embedH.264 with +faststart

Trim long captures first. A short bug repro uploads faster than an hour-long MKV.

Limitation: Re-encode takes time and is lossy. Keep the MKV master.

Which method should you use

SituationStart here
Batch, trim, or a size capGetCompress
Codecs already fit MP4FFmpeg remux
Remux errors or old portalsFFmpeg re-encode

When remux alone is enough

If -c copy produces a playable MP4 under the limit, stop there.

GetCompress fits when OBS folders arrive often, when you need preview and trim before encode, or when format and size must be fixed together. It does not replace a full editor for multi-track mixes.

Related posts