Update readme.MD

readme.MD

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-# obs-virtualcam
-----
+# OBS-VirtualCam
 obs-virutalcam is a plugin for obs-studio , transforming the output video to a virtual directshow device.
-## Features
+# Features
 * **virtual output** : the plugin sink Raw Video & Audio to Directshow Interface
-* **virtual source** : Directshow Interface which can use in other software
+* **virtual source** : Directshow Interface which can use in other software
+# Downloads
+The installer and compressed file can be found in [Release Page](https://github.com/CatxFish/obs-virtual-cam/releases). Using installer is recommended, but if you want to use compressed file to install manually , please follow these three instructions.
+
+1. Unzip OBS-VirtualCam.zip and put it to your obs-studio install folder.
+2. Run CMD as Administrator and register 32bit directshow source
+> command: regsvr32 C:\Program Files (x86)\obs-studio\bin\32bit\obs-virtualsource.dll
+3. Do it again to register 64bit directshow source
+> command: regsvr32 C:\Program Files (x86)\obs-studio\bin\64bit\obs-virtualsource.dll
+
+If you want to Remove the directshow filter , you can also use regsvr32 to do this
+> command: regsvr32 /u C:\Program Files (x86)\obs-studio\bin\32bit\obs-virtualsource.dll
+# Build
+You will need cmake , visual studio2013 ,and build OBS project first. 
+Set following Cmake variables:
+- **QTDIR** (path): QT folder
+- **DepsPath** (path): FFmpeg folder in OBS dependencies package
+- **LIBOBS_INCLUDE_DIR** (path) : Libobs  include folder
+- **LIBOBS_LIB** (filepath) : obs.lib path
+- **OBS_FRONTEND_LIB** (filepath): obs-frontend-api.lib path
+# Directshow output format
+**Video** 
+- YUY2
+- 16:9 or 4:3 aspect ratio
+- height can be divided by 2
+- minimum size 320x240
+
+**Audio**
+- PCM signed 16-bit little-endian 44.1khz