Can you capture/record a video playing on the screen using a recording software(or your custom code) such that every pixel is recorded and there is no loss of information ?
For example, assume you're recording a 1024x768 screen at 30 fps and at 24-bit resolution. So, each pixel will take 3 bytes. On one second, doing the math, you will need to have a minimum of 70778880 bytes, or 67.5 MB of space to store all that. At 32-bit, you will need 90 MB.
Fraps, for instance, I believe it does that, although It uses a special codec for the purpose. In fact, most screencasters might, by the reasons pointed out in the first paragraph, record losslessly or near, since it isn't easy to trade-off compression for efficiency.