What is 1080i?

[syncguy]

1080p has more information than 1080i if both are at the same frame rate, say 60 per second. In case of 1080/60p it will be 60 frames per second but in case of 1080/60i it will be 60 half frames or fields.

If the source is 1080/60p (e.g. PS3 game), converting to 1080/60i will lose half frames and may introduce judder. In this case, a better way could be to downscale 1080/60p to 720/60p at the PS3 and then send 720p to a display that accepts 720p/1080i signal.

If the source is 1080/24p (e.g. blu-ray movie), converting to 1080/60i will not lose information and therefore it can be reconstructed (or deinterlaced) at the display without losing picture quality.