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How to Convert MKV to MP4 Quickly Without Quality Loss

MKV is just a container, storing video, audio, subtitle tracks in a variey of codecs, such as HEVC, H.264, DTS and Dolby Digital audio etc. This means you may encounter MKV not playing error owing to the codec issue. And MKV always saves large-sized video in HD or 4K UHD resolution, which requires high of hardware, leading in MKV playback error on general computers. For example, you may find 4K HEVC MKV files not playing on Windows, MKV plays pixelated/blocky, no sound, black screen or large 4K MKV stutters on computers, mobiles, TVs, Xbox, PS4 etc. To fix such annoying MKV playback issues, you absolutely need to convert files from MKV to MP4 with a free MKV video converter!

WinX HD Video Converter Deluxe is the Best Way to Go!

WinX HD Video Converter Deluxe - Equipped with Full Hardware Acceleration, High Quality Engine and more cutting-edge technologies, it can transcode MKV to MP4 for playback on more devices at the fastest speed while keeping nearly lossless quality. Hundreds of premade presets allow you to convert MKV to iPhone, iPad, Android, Windows Mobile, Xbox or other devices directly.

Strapped for time? Click one of the links below to jump straight to your most interested part.

Part 1: Why Convert MKV to MP4?

1. MKV format or codec is not compatible with your device/player.
Firstly, MKV files won't play on Windows Media Player, QuickTime, PS4 or any players and devices that doesn't support MKV format. And being a video container, MKV is able to store videos of various codecs, such as the rising VP9, HEVC codec, common MPEG4, H.264, VP8, Xvid, or AAC, MP3, DTS Dobly Digital audio codec etc. Thus, there is a great possibility that your MKV player is not accessible for a specific codec (HEVC, DTS etc.), causing errors like MKV no sound, black screen or absolutely not playing.

2. The computer hardware is not good enough to play MKV at 4K resolution.
With the rise of 4K, there are a great deal of 4K UHD MKV videos ripped from 4K Ultra HD blu-ray discs or downloaded from online sites. While unless you upgrade your computer hadware, these 4K (HEVC) MKV files cannot be played smoothly. You may fail to open 4K UHD MKV videos, or get pixelated 4K MKV playback, or dropping frames problems. Learn More: Minimum specs configuration for 4K HEVC MKV playback >>

3. MKV file is always in large size, making it hard for playback and storage.
MKV is publicly known as an ideal format for HD/4K videos. It's natural that a MKV video would occupy several or even dozens of gigabytes. But the problem is, most media players have no access for such a large size video, and the ordinary hard drives or portable devices won't allow you to store the big MKV files as well. For that, you do need reduce 4K MKV file size, and converting MKV to MP4 will have it done partly.

4. MP4 format owns better compatibility, intact quality and ability to retain/abandon original MKV tracks.
On the contrary, MP4 is widely supported by a range of devices, from desktops, HDTVs, game consoles, iPhone iPad to Android smartphones and tablets. And it's able to reserve the highest audio and video quality after converting MKV to MP4. Still, you don't have to worry that the original MKV elements are missing as MP4 is able to retain the multiple audio tracks (e.g. director's commentary), multilingual subtitles, chapter points etc. after MKV to MP4 conversion. Of course, you can also remove some parts of the video, like unwanted language and subtitle tracks to make your MP4 video smaller in size.

Part 2: What Makes WinX HD Video Converter Deluxe Being the First Choice?

You may more or less have used some MKV converter to change MKV format to MP4. But there still are a great deal of users trying to find out an easy yet effective video converter since they get into all sorts of MKV to MP4 converting errors, such as huge quality loss, larger output file size than input, audio/video out of sync, extremely slow converting speed, empty MP4 output and even a failed conversion.

Is there a MKV converter which is free from such conversion errors? WinX HD Video Converter Deluxe is definitely the first choice, as it ensures a fast and smooth MKV to MP4 conversion with original quality, distinctly smaller output file.

Free Download WinX HD Video Converter Deluxe Now!

Average User Rating: ★★★★☆

  1. Convert any videos to 420+ preset profiles, including MP4, MOV, FLV, HEVC, H.264, iPhone iPad, Android, HDTV, Xbox, PS4 and more.
  2. Almost original quality reserved, thanks to the Auto Copy and High-quality engine. It's able to change MKV to MP4 without re-encoding, as well as adopts the same VBR encoding with MKV, in which you can choose the desired quality level and/or a range of allowable bitrates.
  3. Compress MKV videos smaller up to 90% file size reduction, by downscaling resolution, changing codec, tweaking bit rate, frame rate, aspect ratio, cropping frame size, or trimming the video length and so on.
  4. Boast the world's No.1 fast conversion speed, under the action of multiple CPU cores (up to 8), MMX-SSE, Hyper-threading, AMD 3DNow! and GPU acceleration technology. It makes full use of CPU and GPU, accelerating video conversion 47X real-time faster on machines configured with both QSV-allowed Intel processor (2-6th generation) and CUDA/NVENC-enabled NVIDIA GPU.

WinX HD Video Converter Deluxe Advantages Over Online MKV Converters

For the lure of no download and installation, many users may choose free online video converters for MKV-to-MP4 conversion. It does help to transcode single and relatively small MKV files to MP4. While comparing with WinX HD Video Converter Deluxe, it's far backward from for converting 4K UHD, high frame rate HD MKV files.

Differences between online and desktop MKV converters
Differences between online and desktop MKV converters

WinX HD Video Converter Deluxe is a simple-to-use program which comes with advanced features for encoding video files. - Editor's Review from Softpedia)

Part 3: How to Convert MKV to MP4 on PC/Mac - 3 Simple Steps

After downloading and installing WinX HD Video Converter Deluxe onto your computer, you only need 3 simple steps to get MKV converted to MP4.

Free Download WinX HD Video Converter for Windows 10/8/7
Free Download WinX HD Video Converter for macOS Catalina and lower

Step 1: Load target MKV files.

Open this converter and load an MKV file you want to decode from your computer, external hard drive, USB drive: Click + Video button at the top left corner of main interface, and then browse and open target items. If you need to transcode multiple MKV files, simply choose all of them for batch conversion. It will save you much time and energy.

Step 2: Select MP4 in output profile.

After loading source files, Output Profile panel will pop up automatically. In this screen, you will find many preset MP4 output profiles. You can choose one based on your own needs. Here let's select MP4 Video (codec: H.264+ AAC) under General Profiles category for good quality preservation and compression ratio.

Convert MKV to MP4 fast without losing quality
Convert MKV to MP4 fast without quality loss

Optionally, if you want do more with WinX HD Video Converter Deluxe, try the following advanced settings:

  1. Resize MKV video file size: Click gear-shaped setting icon to open up a window where you can compress 4K MKV to 1080p/720p, tweak the bitrate and frame rate to be matchable with the resolution, change aspect ratio to 16:9 for black bars removal.
  2. Trim/crop MKV video: Click Edit, then go to Trim tab and Enable Trim to set the start/end time to cut MKV video length. Or go to Crop & Expand tab and Enable Crop to crop the MKV frame size on the screen. BTW, you can also add external subtitle to MKV below Subtitle tab.
  3. Select the target track or disable unwanted tracks: Back to the main interface, MKV video/audio/subtitle tracks are listed ahead an up-and-down arrow. Click the corresponding arrow, you can select your target video/audio/subtitle track or disable multitracks at all.
  4. Enhance output quality: Go Output profile window, move the slider to HQ/Slow, which will make slow down the converting speed slightly yet with higher quality. Meanwhile, you're always suggested to tick on the box of Use High Quality Engine.
  5. Speed up MKV to MP4 conversion: Make sure you have tick on the Intel/nIVDIA Hardware Accelerator box if your computer is configured with a qualified graphic card. It will accelerate MKV to MP4 conversion speed up to 47X real-time faster.

Step 3: Get it Started Now.

Before any further, you can change the destination folder. By default, output files will be stored in C:\Users\admin\Videos\WinXVideos\. Choose another one by clicking Browse button if you like. Once in place, just click RUN button - a blue round one - to start converting MKV video files to MP4 instantly. After then, you're able to play output MP4 video on desktop, HDTVs, PS4, Xbox, Plex, mobiles and more.

Video Tutorial: How to Convert MKV to MP4 without Losing Quality

Part 4: FAQs on MKV to MP4 Conversion

Q1: I’m trying to export Attack On Titan in 1080p from MKV to MP4 but when it finishes exporting, it adds about 3 minutes and audio gets de-synced. I’m not 100% sure where I could even find details within the video as to why it’s doing this because I’ve never encounter this problem while export on other MKVs.

A1: You can press "j" or "k" on your keyboard to reduce or add delay in VLC player to fix it. But the changes cannot be saved, as you close VLC and open the file in another media player, the audio goes back out of sync. To permanently make audio matched with video, you can try another video converter to re-encode MKV to MP4.

Q2: I'm a so freaking pissed. I've been trying to convert a 720p MKV video file to a 720p MP4 file with NO video quality loss. I've been trying to do this for ALMOST A WEEK with no luck. All these threads go on about "demux" then you "remux" then you whatever "mux" ughhh!! Isn't there a program that I can just drag the file onto, set it to MP4 and get my file with no quality loss?!?!

A2: WinX HD Video Converter Deluxe is what you're looking for, which can transcode MKV to MP4 without quality loss within 3 steps. All you need is to load MKV file > choose MP4 as format > Press RUN button to make everything done.

Free Download WinX HD Video Converter Deluxe to Have A Try!

Q3: I put a roughly 4.1 GB MKV file into Handbrake 1.0.0, selected the AppleTV 3 preset like I always do, while also checking the "Web Optimized" box, and the resulting file came out to about 4.3 GB. I ran the file twice to make sure I didn't screw something up the first time, but had the same result. Any help would be appreciated.

A3: Maybe your source MKV file has a lot of grain to it. Grain will balloon file size tremendously. You can go to RF 22 on the quality slider or use the Denoise Filter in picture settings to remove some of the grain. Either or both will reduce the final file size.

Q4: I'm trying to convert an MKV of Toy Story 2 using DVDFab Video Convertor. Whatever output format I select, the process immediately ends with 'Process completed successfully!' but with no output file.

A4: It looks like DVDFab is not able to detect a GPU, while it should detect Intel QuickSync. You can try with a complete reinstall of DVDFab. If it not working, maybe it's time to consider another Windows 10 video converter.

Q5: The subtitles get messed up after converting MKV to MP4, they're surrounded with a string of random symbols. I've been told that Handbrake cannot preserve "highly stylized" subtitles. Does anyone know how i can adjust the settings to fix this?

A5: You can delete the unwanted subtitle tracks and reserve the one you desired only. Or burning your desired foriegn subtitle to the video is also a good option.

Q6: I'm having an issue with Handbrake converting really slowly. I'm trying to convert an MKV file to an MP4. There's no DVD-ripping involved, and I have a new fast core i3-8100 CPU with 16 GB of RAM, so I would think the conversion process should just fly. But instead I'm only getting 1-2 frames per second.

A6: Handbrake is always going to transcode the contents of the file you give it, leading in slow Handbrake encoding without hardware acceleration. Check whether the Handbrake hardware acceleration is enabled. Actually, if what you want to do is just "repackage" the existing video and audio into a different container Handbrake isn't a great tool for that as it will re-encode everything rather than just passing all ready encoded streams through. Why not try a Handbrake alternative to change MKV format to MP4 without re-encoding.

Part 5: MKV vs. MP4: What's the Difference

Both MKV and MP4 are container to save multimedia data like video, audio, subtitle tracks. But they're quite different and have pros and cons in terms of individual needs.

Platform Compatibility
MKV is a royalty-free open standard developed by the personal team. MP4 is an industry standard committed to replacing the older MPG as a next-generation video/audio packaging format. MP4 has better compatibility than MKV in video editing software and majoy media players and portable devices.

Video/Audio Supported
MP4 is usually encoded with [video] HEVC/H.264/Xvid/MPEG4 + [Audio] AAC/MP3/ALAC, while MKV has more choices, from HEVC, VP9, VP8, Xvid, MPEG4, to DTS, FLAC, AAC, MP3 etc. MKV supports selectable ASS/SSA subtitles and audio tracks while MP4 not. For example, users would like to rip DVD/Blu-ray to MKV, since it can retain everything and keep the tracks to be selectable after ripping. This is what MP4 cannot do.

MKV usually has a larger file size than MP4 videos because it supports additional features, multiple audio and subtitle tracks. But this doesn't mean that MP4 has a lower quality. As both MKV and MP4 are video containers, they can encapsulate the same video and audio stream. If other settings are the same, the video and audio quality is exactly the same.

Related external sources:

[1] MKV: The Matroska Multimedia Container is an open standard, free container format, a file format that can hold an unlimited number of video, audio, picture, or subtitle tracks in one file...
[2] MP4: MPEG-4 Part 14 or MP4 is a digital multimedia container format most commonly used to store video and audio, but it can also be used to store other data such as subtitles and still images...


May Watt

May Watt is a sought-after editor at Digiarty. She is responsible for digital and multimedia world, delivering definitive video and audio related software reviews, enlightening guides, and incisive analysis. As a fan of Apple, May Watt also brings her experience to more readers and focuses on writing of the Apple ecosystem at large.

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