While there is currently a Startup Movie Player system in UE, it can only be used for playing startup movies while the Engine loads up. It cannot be used to play movies in-game, say for instance as part of a UI element or perhaps on a Static Mesh in your level like a movie playing on a TV. This is where the Media Framework comes in, as not only will it allow you to do both of the examples presented above, it will also provide much more general media playback capabilities (outlined below) and is also scheduled to replace the deprecated Startup Movie Player framework in a future engine release.
The Media Framework in Unreal Engine is:
Both Engine & Slate Agnostic
Able to support Localized Audio & Video Tracks
Accessible in the Content Browser, Material Editor, & Sound System
Available for use with Blueprint & the UMG UI Designer
Able to support Streaming Media
Able to Fast Forward, Reverse, Play, Pause, & Scrub Media
Able to support Pluggable Players
As stated above, the Media Framework itself is both Engine and Slate agnostic, which means it can be used in pretty much any application not just the game engine or the Editor. There are layers on top of the framework that provide media playback capabilities to other sub-systems as well, such as Engine, Blueprints, Slate, and the UMG UI Designer. This will cover most expected use cases, such as in-game textures & UI, in-Editor video tutorials, and Marketplace videos.
This page contains several links to additional documentation regarding Media Framework. It is recommended that you check out the Overview page for more of a breakdown of the features of Media Framework as well as the How-To and Quick Start pages for step-by-step instructions to working with Media Framework.
Essentials
Electra Media Player
An overview of how to use the Electra Media Player.
Media Framework Overview
Describes the core features and functionality for video playback using the Media Framework tools in UE5.
Media Framework Quick Start
A guide on how to quickly add and play videos inside your game levels with the Media Framework tools.
Media Framework Tutorials
Links to step-by-step guides for working with Media Framework in Unreal Engine 5.
Media Editor Reference
Breaks down the interface elements and options within the Media Editor used with Media Framework.
Media Framework Technical Reference
Technical information regarding Media Framework in Unreal Engine 5.
Media Asset Reference
Information about Media asset settings.