So I had a .mov file which I was able to play in my game build, but only on Windows. It did not work when I played the game on steamdeck. I did some googling and apparently only certain video codecs compatible with steamdeck (the linux ones below) https://docs.unity3d.com/Manual/VideoSources-FileCompatibility.html So I used VLC player to change the video from .mov to .Webm (VP80 + Vorbis in VLC player). The video still doesn't play on steamdeck, and furthermore it doesn't work on the PC build either now lol. I can watch the .webm video fine in other video players like media player or VLC or whatever, just doesn't work in game. Does it need to be a specific type of webm or am I missing something here, maybe .webm gets handled differently to .mov in unity? Any advice appreciated. Thanks.