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10 June 2019  Amanda J. Brook  Senior Product Manager
 

Summary
Being a open source multi-media container and file format, MKV can save unlimited video, audio, image and subtitle in a MKV file. But how can we merge the MKV file with video, audio and subtitle combination?



Part 1: What is MKV?

Being a multimedia container and video format, MKV supports to save unlimited video, audio, image and subtitle tracks. Similar to other file containers such as AVI, MP4, ASF, but MKV is entirely open source.

MKV supports to contain videos, audios and subtitles information with different code methods even streaming media like RealMedia and QuickTime at the same time, which is its most outstanding characteristic.

The video and audio formats that MKV can contain includes: AVI, Divx, XviD, 3ivX, VP6 and other video codes and PCM, MP3, AC3 and other audio codes.

Part 2: What are Lossy/Lossless Combination of MKV Videos?

Lossless combination of MKV videos: Directly combine the MKV videos without recoding, which will not reduce the video and audio quality of the MKV.

Lossy Combination: Combine the MKV videos after recoding. Generally, this combination method will adapt the lossy compression coding mode (The video and audio quality will be reduced after recoding.). So combining video after recoding is called lossy combination.

Part 3: How to Merge MKV Videos Directly?

Although MKV video has multiple subtitles and audio tracks, users can choose only one of them when merging, splitting or converting. In other words, users should decide to choose related audio track and subtitle when combing MKV videos.

For example, the audio track you choose is English but the subtitle is Chinese. Then the B video you want to combine with A video can not get the audio track with other language like Japanese or English subtitle.

Step 1: Launch Renee Video Editor Pro and choose “Video Toolbox”.
click video toolbox in renee video editor pro
Step 2: Click “Add Files”. Click the “T” button on the right side and select the subtitle for MKV videos manually. Then please check the selection “Merge all files into one”. Finally, please start the combination after confirming the output format and saving place of the video.
select subtiles and combine video in renee video editor
Tips: If you want to select different audio track, please click the button with horn logo on the left side. After selecting the audio track of the MKV video, please check the selection “Merge all files into one”. Finally, please start the combination after confirming the output format and saving place of the video.。

select mkv audio tracks in renee video editor pro

1. Merge MKV Videos with Different Resolution?

Here you may ask “Why black bars appear when I merge multiple videos”. This could be caused by the different resolutions of the videos.

Users will be required to combine videos with same format or resolution when using the video edit tools on the Internet, which users need to adjust the resolution of the video with other codec beforehand. This process may reduce the quality of the video.

But Renee Video Editor Pro will detect the video at first and will combine the video with lossless method if possible.

If the video is in different codec, Renee Video Editor Pro will recode the video without reducing its quality. This will free users from using complicated codec tools to recode the videos’ codec, frame rate and code rate. Besides, this software will not limit the size of the video.

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Multiple Edit ToolsCut Videos & Audios Users are free to cut videos and audios clips with setting start and end time.

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Tips: Here we will make the following demonstration: Convert the video to 1280*720. Then merge it with another video with resolution of 1920*1080.
1. Click “Add Files” and then please select “1280*720” in resolution after clicking “Output Settings”. After confirmation, please click “Start” to output the video.
select video size in output settings
2. As you can see, the resolution of the video has been adjusted.
change mkv video 720p with renee video toolbox
3. Then we import another video with the resolution of 1920*1080. Because Renee Video Editor Pro will recode the new added video automatically, the resolution of these two video will be the same. Then please click “Merge all files into one” and output the video.
renee video toolbox merge mkv videos in same size
4. Open the output video which will not have black bars.
check whether there are black bars in the video

Merge MKV Videos with Usual Method

1. Click “Add Files” and select “Merge all files into one”.
combine all mp4 files into one
2. If you want to add transition between videos, please click “Transition” button on the right side. Renee Video Editor Pro provides nearly one hundred transition effects. Here, we choose “3D/Rotate Y with Zoom” and set the duration to be 2 seconds.
select transition effect between videos
3. After confirming the transition effect, please click “Start” to merge the videos.
add transition and output the mkv videos in renee video editor pro

Combine MKV Videos with Video Overlay

Besides joining videos with usual method, we can also use “Watermark” function in Renee Video Editor to make the video overlay.
1.First, we need to add one of the video to Renee Video Editor Pro. Confirm the output format and saving place of the video. Then click “Watermark”.
use watermark function in renee video toolbox
2. After getting access to the edit window, please click “Add video watermark” button.
add video as the watermark in renee video editor pro
3. Select the video which you want to overlay. And then drag the overlaid video to change the position and the size. You can also cut the overlaid video even adjust the transparency, effects, start time and duration of the overlaid video.
adjust video watermark positiion
4. After checking all the changes you have made, please click “Start” to output the video.
output and save avi video