The purpose of this HowTo is to split videofiles which contain more than one episode of a tv show into single-episode files. So they show up individually within plex, can be played individually and don’t produce any of the weird things that multi-episode files are plagued with.

MKVToolNix is a set of tools to create, alter and inspect Matroska files under Linux, other Unices and Windows. MKVToolnix gui是一个十分优秀的MKV视频编辑工具。MKVToolnix gui功能强悍，能够将多种视频、音频、字幕等格式封装成MKV格式。MkvToolnix 中包含了一个图形界面程序mmg.exe，这样使得制作mkv更简单和直观。.

The tool used is MKVtoolnixGUI
it is freely available for all major PC operating systems.

Therefore the container format of the output files will be MKV.
The input format can be a multitude of containers like AVI, MP4, MKV, MPEG, TS, DIVX and several more.
The quality of the files will remain the same, because mkvtoolnix only remuxes the files, it doesn’t re-encode them.

Mkvtoolnix Combine Files

• start up MKVtoolnixGUI
  (depending on your operating system, this might look a little bit different)
  

• drag the multi-episode file into the window marked by my crude arrow

• the video, audio and subtitle tracks it contains will appear in the window underneath it

• you may want to revise the language code that is assigned to the audio track(s) and the language and ‘forced’ attribute of subtitle tracks so the Plex interface informs you correctly about the languages available.
  Plex’s automatic audio and subtitle track selection feature relies also on these tags to work correctly.
  

• change to the Output tab:
  

• change ‘Split mode’ to ‘after specific timecodes’

• input the timecode of the episode break into the field ‘timecodes’ (you can input several timecodes [separated by comma] if your source videofile contains more than two episodes)
  (I chose to split after 25 seconds, because my example file is only 59 seconds long)

• revise the path and filename in ‘Output file’ to your needs

• click Start muxing

Mkvtoolnix Gui For Windows

You should find 2 or more MKV files in the destination path, their file names appended by a three figure number (DVD Introduction-scene-001.mkv and DVD Introduction-scene-002.mkv for our example file in the screenshots)

Now rename the split episode files according to the Plex naming guide for tv show episodes and add them into your library.

Mkvtoolnix Extract Subtitles

Done.

Mkvtoolnix Extract Audio

If you set above as ‘Split mode’ = “Before Chapters”, you can split your files on chapter markers.
This is particularly useful when you have ripped tv shows and you got only one monolithic file instead of one file for each episode.