A common problem for DSLR and other CMOS sensor-based cameras is that they typically have a lag time between scanning lines of video. Since not all parts of the video are recorded at the same time, this can cause Digital cameras with CMOS sensors often have a rolling shutter, which captures a frame of video one scan line at a time. Due to time lag between scan lines, not all parts of the image are recorded at exactly the same time. If the camera is moving or subject is moving, the rolling shutter can cause distortions.
The Rolling Shutter Repair effect (available in the Distort effect category) can be used to remove these distortion artifacts.
After applying the effect, the following properties are available:
Rolling Shutter Rate: Specifies the percentage of the frame rate which is the scan time. DSLRs seem to be in the 50-70% range, and iPhone is close to 100%. Adjust this value until distorted lines become vertical.
Scan Direction: Specifies the direction that the rolling shutter scan takes place. Most cameras scan top-to-bottom of the sensor, but of course you can mount a camera upside down or rotate a camera completely in the case of a smart phone.
Method: Indicates if optical-flow analysis and pixel-motion retiming will be used to generate the unwarped frames (Pixel Motion), or if a sparse point-tracking and warping method should be used (Warp).
Detailed Analysis: Performs a more detailed point-analysis in the warp. Available when using the Warp method.
Pixel Motion Detail: Specifies how detailed the optical-flow vector field computation should be. Available when using the Pixel Motion method.
Although the Warp Stabilizer effect has a rolling shutter repair effect within it, the standalone version has more controls. There are also times when you want to repair a rolling shutter problem, but you do not need to stabilize the shot.