Both MKV and MP4 are popular file formats. The difference is the former handles more types of data whereas the latter is more widely accepted. So an educated guess as to why you want MP4 over MKV is that something is wrong with your MKV video loading when playing or editing. Re-encoding to reduce file size is yet another possibility.

Here comes the inevitable question: which is the most reliable MKV to MP4 converter?

By reliable, if you mean free and safe, VLC player is a pretty good option, although with such-and-such an error, especially when converting and editing large 4K videos. If you are OK with command lines and somewhat complicated video parameter settings, try FFmpeg or HandBrake. Online cloud MKV to MP4 converter sounds more convenient, however always with limits in file size, length, video resolution, or even bit rate.

If an integration of easy, fast, professional, stable, and no-limit is your thing, then VideoProc is the one worth using, for both remuxing and re-encoding MKV to MP4. By the way, far from being pure-converter software, VideoProc is also an entry-level 4K video editor. It is not freeware, but you do have free access to the trial version, for free downloading and testing if it’s really that good for you.

And the best news here is VideoProc is on sale. A Lifetime License, originally priced at $78.90, is now only $29.95, saving you around fifty bucks. To be clear, the discounted version comes with full benefits from decent tech support to free upgrade. And feel free to keep this HD/4K video converter and editor as long as you want.

Go to VideoProc’s Official Page and Enjoy the Time-Limited Special Offer

First let me walk you through some confusing steps of converting MKV to MP4, mainly related to the difference between remuxing and transcoding.

  1. If it is imperative to keep quality as high as possible, better intact as the original like 4K, then remux MKV to MP4. Just change the container, for example from MKV H.264 to MP4 H.264. Don’t convert the video codec format. File size won’t fluctuate and there should be no quality loss at all.
  2. If simply remuxing MKV to MP4 doesn’t solve your problem, then think about the re-encoding way, like from MKV H.265 to MP4 H.264. Different video codecs use different compression algorithms. Switching from one to another normally leads to data loss, and size increasing or reducing. Don’t know what your video is encoded into? MediaInfo is a great tool to check all video/audio streams info.

Make sure you have already made up your mind about which way to go, and now follow our MKV to MP4 conversion guide below.

Remux MKV to MP4 with VideoProc in 3 Seconds

Step 1. Free download VideoProc (trail version) or purchase a licensed copy with 60% off discount, and get it installed quickly.

Step 2. Run this HD 4K video converter, click “Video” to get into the converter center, drag and drop your MKV file to the main interface, and it will be loaded in no time.

If you fail to import a file like say 4K HEVC MKV video when using other programs, it means the software can’t decode your file. As far as I know, VLC doesn’t support HEVC.


Step 3. Choose an output format, check the “Auto copy” box, and RUN the MKV to MP4 conversion. Remember that if the source is MKV H.264, choose MP4 H.264. If it is MKV HEVC, then set as MP4 HEVC. There is even a specific 4K H.264 in VideoProc, for your convenience. The conversion will be done in a flash.

Watch the video guide on how to convert MKV to MP4

Transcode MKV to MP4 with VideoProc in 3 Steps

For example, re-encode a MKV H.264 video into MP4 H.265 or MKV H.265 to MP4 H.264.

  • Step 1. Download and install VideoProc, then open the software.
  • Step 2. Load your source MKV file or files for batch converting.
  • Step 3. Select your Target Format, enable the Hardware Acceleration Engine, specify the output folder, and click RUN to start the conversion.


MKV to MP4 Is Faster than You Think Now with VideoProc’s Full GPU Acceleration

Re-encoding video, especially 4K files, can be quite computationally intensive, but VideoProc, with full hardware acceleration technology readily accessible, makes it easier for even an old computer with finite resources to run large video transcoding smoothly.

That definitely has a leg up in conversion speed as well. Proper equipment will allow you to enjoy 47x real-time fast speed. CPU usage could be as low as around 8%, so that web pages or online videos can be loaded without a hitch.

As to the balance between conversion speed and quality, novices can simply slide the Quality bar in its parameter panel from Low Quality-Fast, to Default to High Quality-Slow. Experienced users can personalize the bit rate (ABR, CBR, VBR), frame rate, resolution, or even GOP length and B-frames.

Don’t Miss VideoProc’s 4K Video Features

VideoProc has nearly all that a beginner-friendly 4K video editor should have. If needed, edit your 4K MKV video before the conversion. Finetune the colors, rotate or flip the clip to create some special effects. Get your 4K videos trimmed to cut off unnecessary segments and merged later. Download and add subtitles, or denoise and stabilize your 4K footages. GoPro recorded videos always need that.

This 4K video editor also helps with some problems you may have after converting MKV to MP4. If you get stuck in errors like “no sound” or “video and audio not syncing” after converting MKV to MP4 with VLC, load the source MKV file to do the conversion again with VideoProc, or solve the problem by loading the converted MP4 file in VideoProc, resetting the frame rate (it might be caused by variable frame rate), or choosing Recalculate Time Stamp (Force A/V Sync) in its “Edit Video” panel.

Convert MKV to MP4 with FFmpeg

If the command line is acceptable, remuxing MKV to MP4 with FFmpeg is a good way to go. Free get the tool from its official webpage and run the following command:

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

Replace the input with the correct file path where your MKV video is located and the output with where you plan to place it to. It would be quite complicated for beginners to transcode MKV to MP4 with FFmpeg because you need to detail your requirements with more command lines. So better use VideoProc or HandBrake instead.

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