First, you need to visit Facebook.com and on the left of your screen, go to Pages.
Then choose a Facebook page using which you want to live stream a video recording.
In post section of your page press the Live button.
Find the Stream Key tap and copy it.
Open the OBS software (if you don’t have one you can download it at https://obsproject.com/), and at the top left go to “File” > “Settings”
Go to “Stream” Tab
On a “Stream” tab choose a platform you intend to use for streaming (in this case choose “Facebook Live”). Then paste the stream key to the stream key tab, and press “Apply”.
When done with “Stream” configuration, Go back to the OBS dashboard. At the bottom you will see “Sources” tab. Click the plus sign.
Then go to “Media Source”.
Name the source and press “OK”
Click “Browse” and choose the video record you wish to stream, and click “OK”.
When you choose the video the size format can be different from the streaming are format. To fix that right click on video and then click “Resize output (source size)”
This step is extremely important: When you choose a video recording, the “Audio Mixer” Tab will become available. In this tab You must to mute all the audio channels except the “Media Source” one. If you wont do this during your live stream people would be able to hear the sounds your computer’s microphone catches or the your default computer sounds.
Now you can start live streaming by clicking on “start streaming” at the right of your screen.
Also you press play on your video.
When you have done all this go back to “Facebook” and click “Go Live”.
One more important thing: When your live stream has ended don’t forget to stop it, otherwise your video recording will go on loop on your stream or your screen will go dark. Either way, you will continue streaming .
If you have done everything correctly, congratulations! You, are live streaming your video recording on “Facebook”