How to play a video in WPF using byte[] array ?

This looks like a good option:
VideoLAN / LibVLCSharp · GitLab[^]

MediaPlayer is the control for playing video, which uses DirectShow and is limited to the video codecs you have installed on your system.

However, playing video from a byte array is not the usual way and is not performance friendly. You would use a Stream, for anything video related, as having a video file completely loaded into memory is a bad idea. Imagine you playing a 2 hours 4K AVI movie of about 1 Terabyte... how could it be loaded into a byte array in RAM? In this case, you would use a FileStream to load the video from a file and the player would only load small chunks of the video into a static buffer in memory, which would likely consume just a few Megabytes in RAM. Also, because how big is the buffer and how big are the loaded chunks depends on the video format, resolution, pixel format, etc., so the codec is the one responsible for handling that.