Update README in ffmpeg plugin (#566)

Signed-off-by: Guo Jiansheng <[email protected]>
Co-authored-by: Jun <[email protected]>
Co-authored-by: Christopher Degawa <[email protected]>

Author: 3 people

ffmpeg_plugin/README.md

@@ -0,0 +1,73 @@
+# SVT-HEVC ffmpeg plugin installation
+
+These instructions build a version of ffmpeg with the SVT-HEVC plugin.  The steps differ depending
+on whether using a Linux or Windows build machine.
+
+## For Linux:
+
+1\. Build and install SVT-HEVC
+
+``` bash
+git clone https://github.com/OpenVisualCloud/SVT-HEVC
+cd SVT-HEVC/Build/linux
+./build.sh release
+cd release
+make install
+export LD_LIBRARY_PATH=${LD_LIBRARY_PATH}:/usr/local/lib
+export PKG_CONFIG_PATH=${PKG_CONFIG_PATH}:/usr/local/lib/pkgconfig
+```
+## For Windows:
+0\. Setup environment
+``` bash
+Install Visual Studio 2017
+Install msys2-x86_64 to C:\msys64 following instructions found on http://www.msys2.org/
+Run "C:\msys64\mingw64.exe" to open a msys2 mingw-w64 shell.  All subsequent build steps should be done in this shell.
+Execute "pacman -S --needed make mingw-w64-x86_64-cmake mingw-w64-x86_64-gcc mingw-w64-x86_64-yasm mingw-w64-x86_64-SDL2 perl diffutils pkg-config git tar" in the console
+```
+1\. Build and install SVT-HEVC
+``` bash
+git clone https://github.com/OpenVisualCloud/SVT-HEVC
+```
+Option 1: use msvc compiler
+``` bash
+cd SVT-HEVC/Build/windows
+./build.bat 2017 release
+cmake --install . --config Release
+```
+Option 2: use mingw-w64 gcc
+``` bash
+mkdir release
+cd release
+cmake .. -G"Unix Makefiles" -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=C:/svt-encoders -DBUILD_SHARED_LIBS=off
+make -j $(nproc) install
+cd ../..
+```
+The location c:/svt-encoders is used to store a package configuration for the SvtHevcEnc library.
+``` bash
+export PKG_CONFIG_PATH=/c/svt-encoders/lib/pkgconfig:$PKG_CONFIG_PATH
+```
+This instruction will verify that the SvtHevcEnc library can be found when building ffmpeg
+``` bash
+pkg-config --print-errors SvtHevcEnc
+export PATH=$PATH:/c/svt-encoders/lib/
+```
+## For Both:
+2\. Install FFmpeg with SVT-HEVC FFmpeg plugin
+``` bash
+git clone https://github.com/FFmpeg/FFmpeg ffmpeg
+cd ffmpeg
+
+# The patch have been validated on 4.2 and 4.3 release
+git checkout release/4.2
+or 
+git checkout release/4.3
+
+git am ../SVT-HEVC/ffmpeg_plugin/0001*.patch
+./configure --enable-libsvthevc
+make -j $(nproc)
+```
+3\. Verify that ffmpeg can encode media files using the SVT-HEVC plug-in
+``` bash
+./ffmpeg -i input.mp4 -c:v libsvt_hevc -rc 1 -b:v 10M -tune 0 -preset 9 -y test.265
+./ffmpeg -i input.mp4 -c:v libsvt_hevc -vframes 1000 -y test.mp4
+```