In your presentation, you have various videos, images, music and overlays that you would like to use but the streaming platform you are using doesn't offer those features.
Choose a video encoder that will convert the material you need into a data stream that can be directed to the URL of your Stream Provider and authenticated through a login or the use of a Stream Key.
In choosing an RTMP encoder, there are a lot of factors to consider, the biggest ones for many event organizers being user-friendliness and cost. It may be useful to designate a person from your team to master the program you choose and to serve as the technical director for the streams in your event. While it is very manageable to present while also juggling all of the secondary elements of your presentation, it takes practice to do so seamlessly.
One of the most popular software options for encoding is OBS, Open Broadcaster Software an open-source encoder that will allow you to play multiple kinds of media as a part of your stream including overlays and basic video and audio filtering. There is a robust community online creating add-ons and modifications to serve many purposes.
Make sure that an encoder is the right solution for you. Your Livestream provider will frequently allow you to stream from your webcam directly to the stream and may allow you to add elements (filters, overlays, effects) from their native features or to play an uploaded file as a part of your presentation. An encoder serves like a TV studio and may overcomplicate your production depending on your needs.