VLC is one of the easiest way to convert MKV to MP4, but not necessarily smooth. This guide shows you how to convert MKV to MP4 free with VLC and how to fix VLC errors or crashes during MKV to MP4 conversion.

Free Convert MKV to MP4 using VLC

No matter you download your favorite videos from online, or get a copy from DVD/Blu-ray discs, you're in a great chance to meet MKV videos. Though MKV is a universal format that used for storing movie or TV shows in high quality, it suffers from poor compatibility in comparison with MP4. Many mobile devices and programs refuse to recognize and open MKV files. Therefore, it is often necessary to convert MKV to MP4. In this article, we will show you how to use VLC to convert MKV to MP4 for free and how to fix VLC conversion errors.

Part 1. How to Convert MKV to MP4 with VLC?

To begin with, you need to download and install VLC media player on your computer. VLC is a cross-platform program that is compatible with Windows, Mac, and Linux. Make sure get the right edition downloaded. Next I'll illustrate how to convert MKV to MP4 with VLC (v3.0.20) Windows edition. Mac and Linux editions follow the same rules.

Step 1. Open VLC media player, click Media at the top left corner, scroll down and choose Convert / Save to navigate yourself to another window.

Choose Convert / Save Option in VLC

Step 2. Click + Add button to load the MKV video file(s) you want to convert to MP4 in VLC. Alternatively, you can directly drag and drop them to the box. Next, click Convert / Save button at the bottom.

Add MKV Files in VLC

Step 3. Choose Video - h.264 + MP3 (MP4) as the output format.

Note: You can also choose Video for MPEG4 720p TV/device or Video for MPEG4 1080p TV/device, and then choose the wrench tool which will allow us to set more parameters about this format. In Encapsulation, choose MP4/MOV; in Video codec and Audio codec, you can choose different coding ways for the original video and audio tracks, or you can also just check the Keep original video/audio track to change nothing.

Choose Output Format and Path in VLC

Step 4. Select the destination folder and the name for the resulting MP4 file.

Step 5. When all settings are done, simply click Start button to begin converting MKV to MP4 in VLC. And then you should see the progress in the timeline.

VLC supports a whole range of formats, including 3GP, AVI, FLV, MOV, MKV, MP4, MPEG1/2, DivX, MP3, HEVC, and more. So whether you want to transcode MOV to MP4 or convert MKV to MP4 using VLC media player, the VLC tutorial mentioned above is equally applicable to other MP4 conversion.

Part 2. What If VLC Not Working for MKV to MP4 Conversion

Overall, VLC is a free and open-source media player for playing media files, it isn't a specialized video converter. Sometimes it doesn't work well and has been met with many complaints as follows:

"It DOES work, and very well, too, except that it is rather slow."
"It converted mkv to mp4 but it has no audio."
"VLC crashes when converting to MP4. It simply does not work. I tried converting from MKV to MP4, and the file is corrupted and not working."
"Used to work fine on my old computer, but now every conversion ends with failure. Put the quality at 99, but the videos always end up blurry and grainy."

Actually, converting MKV to MP4 using VLC media player may have some problems, such as being slow, no audio, choosing wrong audio track as the default language. Below we will fix the VLC convert MKV to MP4 not working errors one by one.

1. What causes converting MKV to MP4 using VLC to be slow?

VLC media player is exceptionally slow when converting some files, especially those with long duration, complicated codec like HEVC and large 4K file size. This is because VLC is just professional in video decoding as a media player. It takes full advantages of hardware decoding to enable a fast playback speed. When it comes to video encoding to MP4, VLC doesn't make efficient use of your system resources. And therefore, converting speed will be slow. Sometimes, VLC crashes when converting MKV to MP4, especially when the source file is in 4K resolution. You'd better take advantages of GPU-accelerated video transcoder to do the task.

2. How to fix VLC convert mkv to MP4 but no audio error?

There are several causes.

First of all, the MKV container cannot hold certain format, for example, MP4 doesn't support PCM audio. If you are converting MKV to MP4 with PCM audio in VLC, there will be no audio. You'd better change the codec to MPEG 4 (AAC).

Secondly, make sure the audio bitrates you are converting to match. VLC doesn't automatically degrade audio bitrate. If your original mkv video bitrate is 48000 and your audio setting is set to 44100, VLC will generate a converted MP4 file without audio. If the error occurs, you can change the audio sample rate to 48000 Hz.

Thirdly, you can modify strict standard compliance value to make VLC convert MKV to MP4 with audio. Go to Tools > Preferences > Input/Codecs > Video codecs > FFmpeg Changing the 'Strict standard compliance to -2.

3. Why converting MKV to MP4 gives me M4V in VLC?

Some users complained that VLC converted video to M4V with only audio even they chose H.264+MP3 (MP4) profile when converting a video from MKV to MP4 in VLC. If you just want to convert MKV video to MP4 in VLC not M4V, make sure to tick Keep original audio track and rename the file to MP4. Since MP4 and M4V are essentially the same file format, it should work as a normal MP4 on different devices.

Part 3. A Faster and Better Way to Convert MKV to MP4

As you see, there are many different causes for the possible VLC failure on converting MKV to MP4, you have to find the cause and suit the remedy to the case so as to fix the problem. If you have any trouble to convert a video using VLC successfully, for example, crashes, no audio, missing subtitles, black bars, freezes, etc. and can't fix the problem through the above guide or other forums, try VLC alternative MKV to MP4 Converter - EaseFab Video Converter - a fast, easy and high-quality video converter.

● A professional video converter that accepts any kinds of video footages, inclduing Pro 4K/2.7K footage, 4K/HD recordings by mobiles, or videos of any formats.
● You can convert MKV to MP4, MOV, AVI, WebM, iPhone, iPad, Android, PS4, Xbox, TV and 500+ preset profiles.
● It works MKV to MP4 conversion up to 30x real-time faster with the support of full hardware acceleration.
● 3 steps to make all done. Novices can follow the interface prompts to complete the whole process without learning curve.
● Easily adjust video resolution, bitrate, quality, and more properties and it comes with handy vide editor to trim, crop, add watermarks, etc.

How to convert MKV to MP4 on Windows/Mac quickly within 3 steps

Step 1. Add MKV files

Run the Video Converter and drag & drop your MKV files to the program, or click Add Video button to locate the MKV files you want to add. (Note: batch conversion is supported, so you can load more than one file to save time.)


Step 2. Specify the output settings

Then click Profile and select MP4 or HEVC MP4 from Common Video category as the output format. If you want to convert MKV to MP4 for iPhone, iPad, Samsung Galaxy, Google Nexus, etc., you can browse to find any video preset as the output format.

choose output format

For advanced functions

1. Click the Edit button to open the Video Editor window to achieve editing MP4 like trim, crop, image, watermark, effect, subtitles and rotate and etc in the corresponding editing pane.
2. Click the Settings button to open the Settings window to adjust the output video codec, resolution, bitrates, frame rate, aspect ratio, audio codec, channel, volume and etc in the advanced tab.

Step 3. Begin conversion

When you click the Convert button, the process of converting MKV to MP4 with the best VLC alternative will begin in earnest and it will be very fast.

FAQs about MKV to MP4 conversion

1. How do I convert MKV to MP4 for free?

Besides converting MKV to MP4 free using VLC, you can also use Handbrake, FFmpeg, or free online tools like CloudConvert and ConvertFiles.

2. Is it safe to convert mkv to mp4 online?

Yes, to some degree. The online video converters claim they are safe to convert MKV to MP4 with the 256-bit SSL encryption. However, they rely on uploading data to the network for conversion, which lead to a risk of data leakage.

3. Does converting MKV to MP4 lose quality?

It is possible to convert MKV to MP4 without losing quality. You only need to remux MKV to MP4, namely, only change the container format of the video, without re-encoding or changing anything else.