How to Convert MKV to MP4 on Mac, Keep Subtitles

MKV is everywhere in downloaded and archived video because it’s a flexible open container: it can pack a movie, several audio languages, and multiple subtitle tracks into one file. The problem on a Mac is that Apple never supported it. QuickTime won’t open MKV, Preview won’t, and neither will Photos or iMovie.

Convert it to MP4 and it plays everywhere on your Mac. The one thing to watch is those extra audio and subtitle tracks, which need a decision during conversion.

Quick answer: To convert MKV to MP4 on a Mac, remux it if the video is already H.264/H.265, or re-encode if not. Picmal batch-converts MKV files on your Mac with no upload; for track control, HandBrake lets you pick which audio and subtitle streams to keep.

The subtitle and audio-track catch

This is what makes MKV different from a plain format swap:

• Multiple audio tracks: MKV can hold several (different languages, commentary). MP4 supports multiple audio tracks too, but you may want to pick just one to keep the file lean.
• Subtitles: MKV commonly uses SRT or ASS soft subtitles. MP4’s subtitle support is narrower. Your options are to keep compatible soft subs, burn them into the video (permanent, always visible), or export them separately as an .srt file.

HandBrake and FFmpeg give you this control. Simpler tools just take the defaults.

Method 1: HandBrake (best for track and subtitle control)

HandBrake is the free tool to reach for when you care about which tracks survive.

Steps:

1. Open HandBrake and drag in your MKV
2. Set format to MP4
3. In the Audio tab, pick the track(s) to keep
4. In the Subtitles tab, choose to pass through or Burn In
5. Pick a video preset (H.264) and click Start

Worth knowing:

The most control of any free option, at the cost of a busier interface. One file at a time.

Method 2: VLC (plays MKV, converts it too)

VLC opens MKV when nothing else will.

Steps:

1. Open VLC → File → Convert / Stream
2. Drop in your MKV
3. Choose the Video - H.264 + MP3 (MP4) profile
4. Save as File, choose a destination, Save

The catch: Basic converter, limited track control, one file at a time.

Method 3: FFmpeg (remux or full control)

brew install ffmpeg

Fast remux (no re-encode, when codecs are compatible):

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

If the MKV has subtitles that MP4 can’t hold, this may error. Then either drop subtitles:

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

or re-encode with them burned in. FFmpeg gives you exact control over every track.

Method 4: Picmal (batch, on your Mac)

Picmal converts a folder of MKV files to MP4 at once, entirely offline.

Steps:

1. Download Picmal from picmal.app
2. Drag in your MKV files, or a whole folder
3. Choose MP4 as the output
4. Click Convert

What it does:

• Batches a whole folder in one pass
• Runs entirely on your Mac, nothing uploaded
• Fast on Apple Silicon, no size limit, no watermark

Best for: Turning a folder of MKV downloads into MP4s that play in QuickTime and import into editors.

Side-by-side comparison

The short version

• A folder of files, on your Mac: Picmal
• Need specific subtitles or audio tracks: HandBrake
• Fast lossless remux: ffmpeg -i in.mkv -c copy out.mp4

Related guides

• Coming from HEVC or MOV? Convert HEVC to MP4 · Convert MOV to MP4.
• Need it smaller? How to Compress a Video on Mac.
• More formats? Browse the video converter for Mac.
• Only the sound matters? The audio converter for Mac turns FLAC, WAV and M4A into MP3 or AAC.