Best resolution for Photo display?

The best output from the tv is 720p or 1280 x 720 pixels. If you want to use ken burns effects which zooms the photos you need to allow a little more, any more just wastes space. You may want to crop your pictures to suit your tv screen, so crop at 16:9.

I am building 16:9 albums in iphoto just for the tv, if you crop to 16:9 in iphoto it doesn't actually reduce the file size of the photo, to do that you have to use photoshop for example. Generally providing the file size is not enormous I don't bother reducing its size, if it is I usually go for 1600 x 900 pixels. Don't worry about dpi.

1. Can the AppleTV display a resolution higher than 720p, such as for displays capable of 1080i?

It will output 1080i, but basically it is just upscaling 720p

2. Does 1280 x 720 equate to the exact resolution of 720p?

Yes

3. 1600 x 900 resolution is a resolution that is 16:9, however, what if my photo that I want to use does not ahve this many pixels? What is the formula that you are using to calculate a 16:9 format for a photo?

Either take the width in pixels and multiply by 9/16 for the height or take the height and multiply by 16/9 for the width, however most photo applications will let you crop at 16:9

Strangely enough, I had set my Apple TV on the 720p option and noticed that text was looking sharp but pixellated - setting to 1080i the menu text is now smoothed - not sure if it's actually just anti-aliasing it but there's a noticeable difference in the pixellation.


The main thing I'm intrigued about is what is actually doing any scaling - is it a graphics chip or is the processor scaling it in software, in which case there might be an optimum output size for processor efficiency and smoothness of playback.

AC

Equally it's not necessarily obvious if any display setting changes are causing the output to be that different or if the display is internally scaling on top of what the Apple TV sends it.

Stan

1. Does upscaling mean just stretching the pixels, in which case the quality is
actualy less because there are fewer pixels for a larger area?

Not exactly stretching, but you have the idea.

Alley Cat

Strangely enough, I had set my Apple TV on the 720p option and noticed that text was looking sharp but pixellated - setting to 1080i the menu text is now smoothed

This is more a case of it looks better because its actually worse. Text looks pixelated when the picture is sharp, anti=aliasing looks better because it blurs the image, it is not anti=aliasing you are seeing though in this case, it is interlacing which is blurring the picture.