To be precise, you have two solutions at your disposal: install external codecs for Windows Media Player (if you use Windows) or QuickTime (if you use macOS) or resort to all-in-one media players that already integrate everything you need to play any type of video without problems. The same goes for mobile devices with Android and iOS, which also have a wide range of media players capable of playing MKV files.
If you want to know more, take five minutes and discover, with me, how to manage MKV files smoothly: whether you want to play them, convert them or compress them, you'll find the right solutions below. Are you ready to tackle this subject? Are you? Great. So, let's put the chatter aside and get started right away!
MKV Files: What They Are
Before getting to the heart of the tutorial, I'm going to show you what you need to do to play MKV files without problems, I think it's important to explain what we're talking about. In case you don't know it, MKV files, that is Matroska format files, are mainly video contents in which, however, you can also find audio tracks as well as subtitles and chapters.
The result of a project announced back in 2002, it is essentially a "container" format, conceived primarily for flexibility and diffusion. The objective, in fact, is to allow the viewing of contents on all software platforms and to facilitate streaming via the Internet.
Moreover, MKV files are compatible with a large number of native tracks. To be precise, within an MKV file it is possible to find videos of type MPEG-2 and 4, WMV, RealVideo, Flash, Theora, VP8, VP9, H.264 and H.265; audio of type MP2, MP3, PCM, AAC, WMA, Vorbis, AC3, RealAudio, DTS and FLAC; and subtitles of type VobSub, PGS, OGG Writ, WebVTT, ASS, SSA, USF and SRT.
How to Open MKV
Everything clear so far? Well, then I would say that we can find out, together, how to play MKV files on various platforms.
MKV Files on PC
As I told you at the beginning of the post, if to play your multimedia files you usually use Windows Media Player, the multimedia player installed "standard" in Windows operating systems (except the "N" editions), you can achieve your goal by installing the appropriate codecs.
To be precise, I am referring to K-Lite Codec Pack: it is a codec pack totally free and compatible with all Windows operating systems, capable of reading and decoding virtually any existing format, including MKV.
In order to install it on your computer, go to the website of K-Lite Codec Pack and click on the Download Basic link at the top. In the new page that opens, click on Mirror 1. If the download does not start, select the Mirror 2 link.
After the download is complete, open the exe file and click the Yes button in the window that appears on the desktop. After that, press the Next (four times), Install and Finish buttons.
Once the installation is complete, start Windows Media Player by calling it from the Start menu. If you can't find it, read my guide on how to download Windows Media Player to solve it.
Next, drag the MKV file you want to play into the WMP window, select the Video item on the left sidebar and double-click on the movie you just added to your library to watch it.
MKV Files on Mac
Are you using a Mac and want to open your MKV files with QuickTime Player, the default video player of macOS? You can do it, but with some possible hiccups. In fact, Perian, the codec package you need to open MKV files with QuickTime Player, hasn't been developed for quite some time and, although you can install it on the latest versions of macOS, it doesn't always do its job well.
Having said that, since you can't be tempted, here's how to proceed to download Perian: go to the project's website and click on the Download Perian 1.2.3 Now! link on the right side of the page.
Once the download is complete, open the dmg package and double-click on the Perian.prefPane icon in the window that opens. Next, press the Install button in the System Preferences screen that appears.
Next, launch Quick Time Player by invoking it through Launchpad, using Spotlight, Siri or from the Applications folder. Once this is done, click on the File menu (top left corner), select Open File from it and select the MKV file you want to play.
MKV Files on VLC
As an alternative to the installation of codecs, in order to open MKV files on your computer without problems, you can use media players capable of "digesting" the type of file in question, as in the case of those that I have reported in my guide on programs to watch videos. Among the various available, however, I suggest you take advantage of the excellent VLC.
In case you've never heard of it, it's a free and open source media player, which allows you to watch any kind of video - very smoothly even on older hardware - without the need for external codecs. It is available for Windows, macOS and Linux and is very easy to use.
To download it to your computer, go to the program's website and click on the Download VLC button. Then, if you are using Windows, open the .exe file and click on the Yes button in the window that appears on your desktop. Next, press the Next button three times in a row and finally the Close button.
If you are using a Mac, on the other hand, open the .dmg package obtained, move the VLC icon to the Applications folder, right-click on it and choose Open from the context menu. At this point, click on the Open button in order to launch the program and bypass the restrictions imposed by Apple on applications from non-certified developers (this should only be done when running for the first time).
Now that you see the VLC window on your screen, regardless of your operating system, drag and drop the MKV file you are interested in onto it and wait for the automatic playback to start. Alternatively, open the file by clicking on the File menu (top left corner), choosing Open File and then selecting the file you are interested in.
If you want all MKV videos to open automatically in VLC, select any of them with the right mouse button and, if you're using Windows, click on Properties in the menu that appears. In the window that opens, click on the Change button and select VLC from the list of available applications. If you are using macOS, click on the Get Info item attached to the context menu and select VLC from the Open With drop-down list (expand this section of the Properties window if you do not see any drop-down list).
For more details about how VLC works, you can refer to my guide dedicated specifically to this famous software.
MKV Files on Android
Do you want to play MKV files on your Android smartphone or tablet? No problem, it's doable even then. How? Simple, or even more: by using VLC. Yes! The famous media player for computers is also available as an app for mobile devices and has practically the same features as its desktop variant.
So, in order to use it on Android, you must first download and install it by connecting to the relevant section of the Play Store and pressing the Install button. Then, tap on the Open button to launch the app or select its icon in the drawer (the Android screen where you find all the apps installed on your device).
At this point, press the button with the three horizontal lines located at the top left, tap on the Folders item in the menu that appears and select the MKV file you want to play.
Alternatively, you can open a given MKV file with VLC using a file manager or any other app, by selecting the item you're interested in, then the share icon and tapping on the VLC icon in the menu that's shown.
If you're not satisfied with the way VLC works on Android and you're looking for another application that allows you to play your MKV files on the go, I suggest you read my review of the best players for Android, where I've provided you with several alternatives.
MKV Files on iPhone and iPad
Do you use an iPhone or iPad? Also in this case, you can use VLC to play MKV files on your device. To download it, visit the relevant section of the App Store, press the Get/Install button and then authorize the download using Face ID, Touch ID or Apple ID password.
Once downloaded, open the file manager you usually use on iOS or the app where the MKV video you want to play is stored, select it, tap on the share icon and select the VLC icon from the menu that appears to play it. How much easier could it be?
If you are not satisfied with VLC, you can also use other applications to play your MKV files from iPhone and iPad. Which ones? Well, for example, the ones I've mentioned in my article dedicated to video apps.
MKV Files to MP4: How to Convert Them
Would you like to know if there is a way to transform your MKV files into MP4 format videos? Of course there is, that's all you need. You can do it from your computer, smartphone or tablet, just use the right tools and you're done. You ask me what they are? Keep reading and you'll find out.
If you're using Windows or macOS and you're looking for a software to convert your MKV files (but not only), the best suggestion I can give you is without a shadow of a doubt to turn to HandBrake: it's a totally free and open source program that allows you to convert various types of files in MP4 format (as well as MKV) optimizing them for viewing on computers, iPhone, iPad, Android terminals and other devices. It is also well known for its ability to "rip" DVDs.
To download it to your computer, go to the program's website and, if you are using Windows, click on the Download (64-bit) link under the Windows flag icon to start downloading the software.
Once the download is complete, open the .exe file and click the Yes and Next buttons in the window that appears on your desktop. Next, press the I Agree, Install and Finish buttons to complete the setup. Then launch the program by clicking the shortcut added to your desktop or the one from the Start menu.
If you are using macOS, to download the program, after visiting HandBrake's website, click on the Download (Intel 64bit) link located under the Finder icon.
Once the download is complete, open the .dmg package and drag the HandBrake icon to the Applications folder of macOS, right-click on it and select Open from the context menu. Then, click the Open button to open the application and bypass the restrictions that Apple imposes on applications from non-certified developers (this should only be done when running it for the first time).
Now that you see the software window on your screen, drag and drop the MKV file you want to convert to MP4, select the Summary tab in the middle of the window and choose MP4 from the Format drop-down menu. You can also adjust the settings for audio, subtitles, codecs, etc. from the central part of the window.
To finish, click the Browse button at the bottom of the window, indicate the location on your computer where you want to save the converted movie and press the Start Encode/Start button at the top left to start the conversion process.
Media Converter (Android)
If, on the other hand, you want to convert MKV files to MP4 format from your Android smartphone or tablet, the best suggestion I can give you is to use the Media Converter app, which is free and also quite intuitive. It allows you to convert virtually any video file to any format and set the bitrate, resolution and audio sample rate of the output file.
To download it to your device, visit the relevant section of the Play Store and tap on the Install button. Then, launch the app by pressing the Open button that appears on the screen, or by selecting the relevant icon that has just been added to the drawer (the Android screen where all apps are grouped).
Now that you see the main screen of Media Converter, select the location on your device where the file you want to convert is saved, press the Convert to mp4 button and wait for the conversion process to finish. By default, the final file will be saved in the same location as the original one.
If you would like to customize the conversion parameters before starting the conversion, click the Expert mode button, select an MP4 profile from the Output Profile dropdown menu and make any other customizations regarding duration, quality, sound etc. using the available options. Finally, press the Convert button.
The Video Converter (iOS)
If you're using an iOS device, to convert your MKV videos to MP4 you can turn to The Video Converter app: it's a free and easy-to-use solution with which you can convert all major video file formats in a few taps. The only thing you need to take into account is that not all output formats are free, MP4 included. To get around this limitation, you have to unlock the appropriate pass via in-app purchases (at a cost of €4.49).
To download it on your device, go to the relevant section on the App Store and press the Get/Install button. Then authorize the download via Face ID, Touch ID or Apple ID password. Once downloaded, launch the app by pressing the Open button or by selecting the relevant icon that has been added to the home screen.
Now that you're viewing the main screen of the application, select the location or app where the MKV file you're interested in is saved, choose the MP4 Video (.mp4) option from the To drop-down menu and tap the Convert button to proceed. Finally, indicate where to save the output file.
MKV File Too Large: How to Fix
For the sake of completeness, I think it is necessary to explain how to reduce the size of an MKV file that is too large, so as to "lighten" it. To learn more, please read on: everything is explained in detail below.
In addition to being used to convert MKV files to MP4 format, HandBrake, the software for Windows and macOS I told you about in the step a few lines above, can also be used to compress movies when they are too big.
How do you do it? Nothing could be simpler: after downloading and installing the program, launch it, drag and drop the MKV file you are interested in onto it, click on the Presets button at the top right and select the name of the device on which you intend to play the movie or, alternatively, choose a generic profile.
Make sure that in the Presets tab (in the middle) the MKV option is selected in the Format drop-down menu (if not, you can do it yourself), press the Browse button at the bottom to choose the output folder and click the Start/Start Encode button at the top to proceed.
Video Compress (Android)
Let's see how to reduce the size of an MKV file from Android. In this case, I recommend using the Video Compress app, which allows you to reduce the weight of your video files by selecting the final quality yourself. It supports all popular video formats and is very easy to use. It's free, but through in-app purchases (at a cost of €2.90) it allows you to unlock additional features
To download it, visit the relevant section of the Play Store and tap on the Install button. Once installed, press the Open button that appears on the screen or launch the app by pressing on its icon that has just been added to the drawer (the Android screen where the icons of all applications are grouped).
Now, select the MKV file you're interested in using the app's internal file manager, choose the Compress Video option, indicate the degree of compression you prefer from the various options in the list and wait for the process to be completed. Once the process is complete, the compressed movie will be saved in the device's gallery.
Alternatively, you can adjust the video compression parameters yourself by going to the custom tab and moving the sliders under the Video Resolution and Bits Per Second headings as you wish. To start the compression, then, press the Compress Video button.
If you want, before starting the video compression process, you can also choose to remove the audio from the video and make it black and white by selecting the appropriate options at the top of the screen.
Smart Video Management (iOS)
If what you're using is an iPhone or iPad, you can use the Video Compressor app, which offers the ability to compress all major video file formats and reduce their size by up to 80%. It's easy to use and it's free, but it offers in-app purchases (at a cost of €3.49) to unlock additional features.
To use it, directly from your device visit the relevant section of the App Store, press the Get/Install button and authorize the app download via Face ID, Touch ID or Apple ID password. Next, tap on the Open button to launch the app or press on its icon that has just been added to your home screen.
Now that you see the app's main screen, select the MKV movie you want to compress from your device's gallery or iCloud by tapping on the item at the top left, and indicate how much you want to reduce the weight of the movie by selecting one of the available options from the menu that appears.
If you don't want to use one of the available presets, select the Compress Video Custom Settings item and set the compression parameters yourself by adjusting the resolution, FPS and audio and video bitrate.
Regardless of your choice, wait until the compression is complete and then indicate the location where you want to save the output file. It was easy, wasn't it?