“As we know, most 1080p movies are compressed using x264 in an mkv container. Now I have some m2ts files which I’d like to compress into mkv but maintaining a decent quality. Is there an easy and fast way to make it?”
Have you got it? The tutorial will show you the easiest method to convert
m2ts to mkv by using Moyea MTS/M2TS Converter. It is powerful to convert
m2ts to mkv with excellent output quality.
Preparation: Free download
Moyea MTS/M2TS Converter here, install and run it
Step 1: Click the “Add” button to import m2ts files into it
Step 2: Select output format as mkv
Step 3: Click the “Convert” button to start m2ts to mkv conversion

Tips:
1) Click the “Settings” button, you can set bit rate, frame rate, codec, size of Video and codec, size, sample and channels to get better output quality.
2) Click the “Edit” button, you can do the following jobs, like cropping, trimming, adding watermark/effect and so on to improve and perfect your m2ts files.
3) Click the “Snapshot” button, you can capture any current picture you like when viewing Video under the preview panel.
4) Tick the checkbox “Merge into one file” to combine or join several m2ts files into one.