He discusses rolling shutter in relation to HD-DSLR cameras being used to capture moving images. He describes rolling shutter by saying, "Cameras that use ... CMOS, chip are unable to capture the entire scene in a single instant. Instead, the image data is captured line by line as if a mechanical shutter was rolling through the device."
Just like the iPhone distorted images the HD-DSLR camera can have similar distortion in the video images if the camera is moved quickly during filming. Software solutions are being developed by the The Foundry in the UK has developed a Rolling Shutter plug-in for After Effects.