Added docs for MP4Writer example.

Author: hgmarques

docs/articles/vision/mp4_writer.md

@@ -5,23 +5,22 @@
 :::
 
 ## Summary
-[FFMPEG](https://website-name.com)
+This example shows how to save a MP4 video using [FFMPEG](https://website-name.com)
 
 
 ## Details
 0. Before running workflow download and unzip [ffmpeg](https://github.com/BtbN/FFmpeg-Builds/releases/download/latest/ffmpeg-master-latest-win64-gpl-shared.zip) to a folder in your computer. 
 
 1. Write the frames from a camera into ImageWriter, but in the path, instead of a file, you will add a pipe: \\\\.\pipe\video. Every frame that is written in the pipe is going to be sent the process in 2.
 
-2. Start a process where the filename points to the ffmpeg executable \[ffmpeg\]\bin\ffmpeg.exe and the arguments are those of ffmpeg.  
-Here we are using:  
+2. Start a process where the filename points to the ffmpeg executable \[ffmpeg\]\bin\ffmpeg.exe and the arguments are those of ffmpeg. Here we are using:  
 -y -f rawvideo -vcodec rawvideo  -s 640x480 -r 30 -pix_fmt gray -i \\\\.\pipe\video -c:v libx264 -b:v 5212K -maxrate 5212K -bufsize 5M "myvideo.mp4"  
 
-Options that might need to be adapted for your situation are:
-- the size (width and height) of the input images (-s)
-- the frame rate (-r)
-- the name of the output video (last parameter)
-- in case the encoding is rather slow, you might want to append the option '-preset ultrafast' to speed it up.
+  Options that might need to be adapted for your situation are:
+  - the size (width and height) of the input images (-s)
+  - the frame rate (-r)
+  - the name of the output video (last parameter)
+  - in case the encoding is rather slow, you might want to append the option '-preset ultrafast' to speed it up.
 
  ## Follow-up
 For additional information on the encoding options provided by ffmpeg consult the [documentation](https://ffmpeg.org/ffmpeg.html).