What DIMENSIONS and FORMATS should I use for my media?
Apple TV 4
Video and image dimensions
For the Media Media Area, you can use 1920×1080 px or 1280×720 px to fit the frame. This is the size of Full-HD or HD in video.
For any other image sizes you have an option to scale to fit or to scale to fill (Note: this is only available for images not videos).
Video file formats
Use mp4 or mov with H.264 for best results in video quality and size.
Apple defines this for the Apple TV 4: H.264 video up to 1080p, up to 60 frames per second, High or Main Profile level 4.2 or lower.
Find more details on apple.com.
Logo file format
For the Logo Area you can use PNG with transparency. The maximum space for logo is 340×180 px.
Apple TV 4K
You can use up to 2x the pixel size as above.