I recently found a simple way to change the width of videos embedded directly into Obsidian notes using HTML:
Instead of using the standard Obsidian embedding syntax (![[video.mp4]] ), you can directly embed your video with HTML like this:
<video src="your-video-file.mp4" controls width="600"></video>
Just replace your-video-file.mp4 with the filename of your video and adjust the width attribute (width="600" ) to your preference (pixels or percentage).
Hope this helps!