Tuesday, January 11, 2011

The Difference Between HD and SD for dummies

It is difficult for some people to wrap their head around the notion of resolution, particularly when rendering 3D graphics. Most people think smaller resolutions make things “bigger” on their display because of the way setting lower resolutions works with your OS (lower resolutions appears to make your icons larger). This idea is incredibly misleading.

To accurately describe how resolution works and what the difference between 480p and 1080p is, lets imagine a painting drawn on a large canvas. It is immaculately detailed, you can see very small blades of grass bending under the foot of the subject of the painting, you can see the freckles on his nose. It looks great. Someone buys the painting and hangs it in his bedroom above his bed, but he’d like a smaller copy to put on a display in his livingroom, so he has the copy scanned and re-printed on a much smaller canvas.

Not long after, disaster strikes and he loses the original painting, but manages to keep the smaller copy he’s made. He wants the large painting in his room again, so he has the smaller painting scanned and printed on a larger canvas. But let’s think about it: when the painting was shrunk, it didn’t have as much space for as much detail, so now that he’s blown it up again he can see the subject of the painting no longer has freckles, and the blades of grass have become very thin wispy lines under the subject’s foot. Much of the detail is lost when you try to stretch a smaller copy across the same area as the original because the smaller copy doesn’t have enough canvas to accurately convey the information of the freckles and the blades of grass. There just isn’t enough room.

Here are two screens. One is Twilight Princess as it would appear playing through a wii, as if I have ripped it directly from a 1080p display. The image is blown up to the displays native resolution, but it is clear that the console is running it at a much lower pixel count. The second screen is Twilight Princess as it appeals in true 1080p running through an emulator on a computer: you can see that the image is much less blocky, and the edges of objects are much cleaner because the game has more pixels to draw to. I recommend you open these two up in a separate tab, “zoom” them so they are bigger than your computer’s resolution, and then swap between the two tabs to get the full effect of the difference. This is important to do because the blog shrinks them to fit to the page, which makes it impossible to see the what I am talking about.

To drive the point home, here is what the game looks like ripped directly from the wii’s buffer. You can see that this screen is much smaller than the other two, and you can see that trying to stretch this screen out would result in the first screen I showed you:

Stay fresh,


  1. HD just has more polygons.

  2. So HD version has different FOV and bigger resolution? =ddd