Comments

Birk Binnard wrote on 7/10/2010, 3:31 PM
Rolling shutter is an image distortion effect that is fundamentally inherent to electronic image sensors, given certain conditions apply.

Image sensors are a rectangular array of photocells. Extracting an image from a sensor means reading the data value from each cell. Suppose the sensor has an array size of 1920x1080. This means it has 1080 rows if 1920 cells each.

For various reasons the cells are read one row at a time. This means there are a total of 1080 read operations required to read the entire image, and each read has to pull in the data from 1920 individual cells. ALl this takes a small but finite amount of time.

Suppose you are taking a video at 30fps. That means the entire sensor has to be read 30 times each second. Furthermore, suppose you are panning a scene left to right, and there are some vertical objects in the scene (like light posts or building edges.)

If you pan fast enough the image seen by the sensor will shift slightly for each frame, and even beyond that for each row of sensors scanned. So the resulting full frame image will end up with the vertical objects slightly tilted.

Panning is tricky business and it takes a while to learn just how fast you can pan without losing focus (which is much more likely to happen) or incurring rolling shutter effects. A good, slow, smooth pan keeps everything in sharp focus and does not introduce any visible levels of distortion. With a hand-held camera (GH1 in my case) I find this takes a lot of concentration.
RoyfromDurham wrote on 7/11/2010, 12:18 AM
Thanks Birk for your explaination and I now know how to avoid any such problem.
Melachrino wrote on 7/11/2010, 9:07 AM
Is this an external stabilizer or is it part of DVDA ? If the latter, where is it ?
I have resorted to Deshaker which works quite well to reduce handshaking effects. Since the Canon HV20 has a rolling shutter, it makes a big difference invoking the correction for it in Deshaker. Otherwise you get slanted vertical objects or a swimming effect.

Strictly speaking, the rolling shutter artifact is caused by the image storing process in the CCD or CMOS cells and not by the readout. It is determined by the scanning speed from top to bottom of the array during the exposure sequence. Better comercial CCD's and CMOS expose the array and store the image much faster such that there is little observable slant on normal pans. Then the readout can be as slow as required but fast enough for the next frame capture.

Some camcorders allow you to control the time exposure to reduce smear and slanting effects on motion but at the expense of light sensitivity.

Earlier CCD's and CMOS were very slow and resulted in objectionable smear during motion. With current progress, they are both much faster now, and more sensitive, so that smear and slant are considerably reduced. With more progress in speed and sensitivity these artifacts may hopefully be reduced to where they are not observable.
musicvid10 wrote on 7/11/2010, 1:44 PM
There is no stabilizer option or plugins for DVD Architect. It is an authoring program, not an editor or processing application.

The OP may be confusing DVD Architect with Vegas Movie Studio 10, which is a separate application, that includes a stabilizer function with rolling shutter correction.