Question: I am looking for a solution to control my computer mouse just with my hands and a webcam. The goal is to combine it with voice input to let me move more freely in front of my desk.

It should support the usual mouse actions:

* position mouse pointer, left click, right click, middle click, scroll up, scroll down
* optionally: scroll left, scroll right

Answer: 
Use [ffmpeg](http://ffmpeg.org)

```
ffmpeg -f concat -i mylist.txt -c copy output.mkv

```

Put path to your MKVs in mylist.txt in line seperated manner. You don't even need to think about re-encoding. The codecs will be copied as-is. Quality unchanged.
This is what I use

<https://www.fosshub.com/MKVToolNix.html>

You can see the result here

<https://www.youtube.com/watch?v=2_TCmWRUQrI>

Basically a 3:20 video is combined with a 30 minutes video

Notice to do this you need to ensure you that you append video to another video

The first time I am doing it I just combine 2 video. The result is one mkv files that contain 2 chapters.

No I want to append one video one after another.

[https://www.macworld.com/article/223409/how-to-combine-two-dvds-into-a-single-movie.html#:~:text=Launch%20MKVToolNix%20and%20in%20the,navigate%20to%20the%20second%20movie](https://www.macworld.com/article/223409/how-to-combine-two-dvds-into-a-single-movie.html#:%7E:text=Launch%20MKVToolNix%20and%20in%20the,navigate%20to%20the%20second%20movie).

> 
> Launch MKVToolNix and in the window that appears, drag your first
> movie file into the Input Files area (or click the Add button,
> navigate to the file, and then add it). Then click the Append button
> and navigate to the second movie.
> 
> 
> 

That is how. Do not simply add 2 videos.