Does HandBrake convert MKV to MP4 without losing quality?

Not exactly. HandBrake always re-encodes the video, and every re-encode costs one generation of compression. At RF 20–22 the loss is hard to see, but it exists, and the encode takes real time. A truly lossless conversion requires copying the streams into the new container without decoding them — a remux — which HandBrake does not offer for video.

Why is HandBrake so slow at converting MKV to MP4?

Because it decodes every frame and compresses it again from scratch. A feature-length 1080p file means re-encoding 150,000+ frames, which takes anywhere from several minutes to over an hour depending on your CPU and the encoder preset. A remux skips the decode/encode entirely and finishes in roughly the time it takes to copy the file.

Why did HandBrake save my file as .m4v instead of .mp4?

An .m4v file is the same MP4 container with a different extension — older HandBrake versions on Mac used it by default. Renaming the extension to .mp4 is safe, or you can change the default in HandBrake's preferences.

Does HandBrake keep the subtitles from my MKV?

Only if you tell it to. Subtitle tracks are not carried over automatically — open the Subtitles tab and add each track you want. Text subtitles (SRT/ASS) can be passed through as soft subtitles in an MP4; bitmap subtitles like Blu-ray PGS can only be burned into the picture permanently.

When is HandBrake the right tool for MKV files?

When you actually need to change the video: shrink a file that's too big, convert a codec your device can't play, hard-burn subtitles, or batch-apply a preset to a season of episodes. If you only need the same video in an MP4 container, a remux does it in seconds with zero quality loss.

July 22, 2026

How to Convert MKV to MP4 with HandBrake — and When You Shouldn't

HandBrake is the tool most guides recommend for turning an MKV into an MP4, and it does the job reliably on Windows, macOS, and Linux. This walkthrough covers the exact steps and the settings that matter. It also explains the part most guides skip: HandBrake re-encodes your video every time, which costs time and a little quality — and for the most common MKV files there is a faster, lossless alternative.

Converting MKV to MP4 in HandBrake, step by step

1. Install HandBrake and open your MKV

Download HandBrake from handbrake.fr (it's free and open source — skip any other download site). Launch it, click Open Source, and pick your .mkv file. HandBrake scans the file and lists its video, audio, and subtitle tracks.

2. Pick a preset

For most files, Fast 1080p30 under General is the sensible default: H.264 video, AAC audio, wide device compatibility. If your source is 4K, use a 2160p preset instead so HandBrake doesn't downscale it.

3. Set the container to MP4

In the Summary tab, set Format to MP4. Ticking Web Optimized moves the file's index to the front so it starts playing before it fully downloads — worth enabling if the file will ever be streamed or shared.

4. Check the quality setting

In the Video tab, quality is controlled by the RF slider — lower means better. RF 20–22 is a good range for 1080p; going below ~18 inflates the file with little visible gain, and above ~24 the loss starts to show. The encoder preset (Fast, Medium, Slow…) trades speed for compression efficiency, not quality — Slow produces a smaller file at the same RF but takes much longer.

5. Bring your subtitles along

HandBrake does not carry subtitles over automatically. Open the Subtitles tab and add each track you want to keep. Text tracks (SRT, ASS) can stay as selectable soft subtitles; bitmap tracks from Blu-rays (PGS) can only be burned into the picture — permanently.

6. Start the encode and wait

Click Start Encode. This is where HandBrake's nature shows: every frame is decoded and compressed again, so a feature-length 1080p file takes anywhere from ~10 minutes on a fast desktop CPU to well over an hour on an older laptop. Batch more files by adding them to the queue.

The catch: HandBrake always re-encodes

HandBrake is a transcoder. It has no mode that copies the video stream untouched — even if your MKV already contains H.264 video that MP4 supports natively, HandBrake decodes all of it and compresses it again. That has two costs: the encode time above, and one generation of quality loss. At RF 20 the loss is hard to spot, but it is real, and it compounds if the file gets converted again later.

Here is the thing about MKV and MP4: they are containers, not video formats. The overwhelming majority of MKV files carry H.264 or H.265/HEVC video — codecs the MP4 container accepts as-is. For those files nothing needs to be re-encoded at all. The streams can be copied bit-for-bit into an MP4 container in seconds, with output quality identical to the source. That operation is called a remux, and it is what our free in-browser MKV to MP4 converter does by default — no install, no upload, and your file never leaves your device.

	HandBrake (re-encode)	Remux (this site)
What happens to the video	Decoded and re-compressed frame by frame	Copied bit-for-bit
Quality	One generation of loss (small at RF 20–22)	Identical to the source
Time for a 2 GB file	10–60+ minutes, CPU-bound	Seconds
File size	Changes — depends on quality settings	Essentially unchanged
Install required	Yes — desktop app	No — runs in the browser
Best for	Shrinking files, changing codecs, burning subs	Making an MKV play as MP4

So which one should you use?

Use HandBrake when you need to change the video itself: shrink a 20 GB Blu-ray rip to something that fits on your phone, convert a codec your TV can't decode, hard-burn subtitles into the picture, or run a whole season through one preset overnight. Those are re-encoding jobs, and HandBrake is excellent at them.

Use a remux when the only problem is the container — the file plays fine in VLC but your iPhone, smart TV, or video editor rejects the .mkv extension. That covers most everyday cases, and re-encoding for it is pure waste: you spend 40 minutes of CPU time and a quality generation to end up with the same video you already had. On a Mac there's a dedicated guide for this exact situation: convert MKV to MP4 on Mac without installing anything.

One honest caveat: the rare MKV with VP8/VP9 video does need a re-encode to become a universally playable MP4 — our tool detects that automatically and falls back to re-encoding, telling you which path it took. And for files over 1.5 GB, a desktop tool like HandBrake (or FFmpeg) is the right call, since browser memory limits cap what a web-based converter can handle.

Skip the 40-minute encode

If your MKV just needs to play as an MP4, drop it into the free MKV to MP4 converter — most files finish in seconds via lossless stream copy, entirely in your browser, with nothing uploaded anywhere.