Added matroska option to VideoEncoder example (altnerative to ffmpeg)

Author: Erol444

docs/source/includes/container-encoding.rst

@@ -1,3 +1,14 @@
 Encoded bitstream (either MJPEG, H264, or H265) from the device can also be **saved directly into .mp4 container**
 with no computational overhead on the host computer. See `demo here <https://github.com/luxonis/depthai-experiments/tree/master/gen2-container-encoding>`__
-for more information.
+for more information.
+
+**Matroska**
+
+Besides ``ffmpeg`` and ``.mp4`` video container (which is patent encumbered), you could also use the ``mkvmerge``
+(see `MKVToolNix <https://mkvtoolnix.download/doc/mkvmerge.html>`__ for GUI usage) and ``.mkv`` video container
+to mux encoded stream into video file that is supported by all major video players
+(eg. `VLC <https://www.videolan.org/vlc/>`__)
+
+.. code-block::
+    
+    mkvmerge -o vid.mkv video.h265