Add a section for dependencies

readme.md

@@ -2,6 +2,30 @@
 
 This project allows you to download and convert YouTube videos, to watch them on your PSP.
 
+#### Dependencies
+
+- youtube-dl
+
+Install this package from pip using the command below.
+
+```bash
+pip install --user youtube-dl
+```
+
+Or you can install it from source, using the commands below.  
+When installed from source, youtube-dl depends on `python` (Python 2) and `pandoc`.
+
+```bash
+git clone https://github.com/ytdl-org/youtube-dl.git
+cd youtube-dl
+make
+make install
+```
+
+- ffmpeg
+
+You can install this package from your distribution repositories.
+
 #### Installation
 
 Clone the repository to your computer.