docs(INSTALL): Remove info about unsupported Debian 8

Fix #4574

INSTALL.md

@@ -28,7 +28,6 @@
     - [openSUSE](#opensuse-toxcore)
     - [Slackware](#slackware-toxcore)
     - [Ubuntu >=15.04](#ubuntu-toxcore)
-  - [FFmpeg (Debian 8)](#ffmpeg)
   - [sqlcipher](#sqlcipher)
   - [Compile toxcore](#compile-toxcore)
   - [Compile qTox](#compile-qtox)
@@ -260,11 +259,7 @@ sudo pacman -S --needed base-devel qt5 openal libxss qrencode ffmpeg
 
 #### Debian
 
-**Note that only Debian >=8 stable (jessie) is supported.**
-
-If you use Debian 8, you have to compile FFmpeg manually and add backports to
-your `sources.list`. Adding backports:
-http://backports.debian.org/Instructions/
+**Note that only Debian >=9 stable (stretch) is supported.**
 
 ```bash
 sudo apt-get install \
@@ -289,9 +284,6 @@ sudo apt-get install \
     yasm
 ```
 
-**Go to [FFmpeg](#ffmpeg) section to compile it.**
-
-
 <a name="fedora-other-deps" />
 
 #### Fedora
@@ -412,69 +404,6 @@ sudo apt-get install \
     qttools5-dev-tools
 ```
 
-### FFmpeg
-
-If you have installed FFmpeg earlier (i.e. you don't run Debian 8), skip this
-section, and go directly to installing [**toxcore**](#toxcore-dependencies).
-
-To get ffmpeg compiled and put in directory `libs`, run this script in qTox
-directory:
-
-```bash
-[ ! -e "libs" ] && mkdir libs   # create directory libs if doesn't exist
-[ ! -e "ffmpeg" ] && mkdir ffmpeg
-
-cd libs/
-export PREFIX_DIR="$PWD"
-
-cd ../ffmpeg
-wget http://ffmpeg.org/releases/ffmpeg-3.2.2.tar.bz2
-tar xf ffmpeg*
-cd ffmpeg*/
-
-
-./configure --prefix="$PREFIX_DIR" \
-            --enable-shared \
-            --disable-static \
-            --disable-programs \
-            --disable-protocols \
-            --disable-doc \
-            --disable-sdl \
-            --disable-avfilter \
-            --disable-avresample \
-            --disable-filters \
-            --disable-iconv \
-            --disable-network \
-            --disable-muxers \
-            --disable-postproc \
-            --disable-swresample \
-            --disable-swscale-alpha \
-            --disable-dct \
-            --disable-dwt \
-            --disable-lsp \
-            --disable-lzo \
-            --disable-mdct \
-            --disable-rdft \
-            --disable-fft \
-            --disable-faan \
-            --disable-vaapi \
-            --disable-vdpau \
-            --disable-zlib \
-            --disable-xlib \
-            --disable-bzlib \
-            --disable-lzma \
-            --disable-encoders
-
-
-make -j$(nproc)
-make install
-
-cd ../../
-
-export PKG_CONFIG_PATH="$PWD/libs/lib/pkgconfig"
-```
-
-
 ### toxcore dependencies
 
 Install all of the toxcore dependencies.
@@ -584,15 +513,6 @@ cmake .
 make
 ```
 
-If you had to compile [FFmpeg](#ffmpeg) manually, run this script from qTox
-directory before starting qTox:
-
-```bash
-cd libs/lib
-export LD_LIBRARY_PATH="$PWD"
-cd ../../
-```
-
 Now you can start compiled qTox with `./qtox`
 
 Congratulations, you've compiled qTox `:)`