Skip rendering duplicate frames?

When I make a character, I usually make and render a test animation with him. Usually, I set the first 30 or so frames of the animation as the character in his initial position. That adds up a lot of render time just to render the same frame over and over again. Is there a way to make it so it only has to render that frame once, and skip right to frame 31?

I also heard someone talking about being able to render static backgrounds and objects once, and only have to render the moving parts of the frame from there on out.

Can anyone tell me if either of these are possible, and how?

I’ve read tales (from eeshlo, I think) that this type of rendering may be possible in the near future. The idea is to skip rendering of any unchanged or “static” pixels in the scene and simply duplicate them. Sort of like a codec but with full frames. For now you’ll just need to slap a static image of the first frame in the compositor then begin rendering with frame 31. If you need instructions I’m sure someone has the time to help you with that.

You can change the Sta: (Starting) frame number to 31 on the ANIM panel in the render context buttons.