Digital camera 'flickers' when in HD video mode

[protege]

I've been playing around with the various features of my Fuji S3200 digital camera. This particular model can record short videos with sound. Anyway, while down at the tracks today, I thought I'd shoot a set of locomotives coming through town. So naturally, I set the camera to video, and started recording. But, as I was shooting, I saw some pink and purple shapes flickering at the top and bottom of the screen. From what I can tell, it only seems to happen in 720 HD mode. The other two modes--640 and 320, are fine. Anyone know why that happens?

[Salesmonkey]

This is more of a guess than a useful answer, so you may want to disregard it or think of it just as a pointer - experts please join in -

The sensor array in a digital camera takes a read from all sensors at one time, and saves it as a picture. Then it reads another picture, and then another. By showing all pictures one after another, it is much more similar to a film movie camera than an electronic video camera

In a camcorder, the sensor might start at the upper left-hand of its sensor array, and start reading the states of the individual light sensors, row after row, until it reaches the bottom right hand one, when it loops over. By matching the sensor read to time, it makes a moving image.

I am guessing that the pink and purple shapes are rectangular, or even square, and they show up for just one frame. That's because there's a mild encoding error when the camera tries to save the "picture" of that frame. You would never notice these errors in a camcorder because the error would be a single pixel off color, less than the human eye can discern.

As 720 seems like the highest mode, it's probably also the hardest on the camera's processor. You were also filming locomotives moving through town, so there were lots of changes in the viewable area.

I would suggest using a lower resolution for "action" scenes, but I bet you can still use 720 mode for more still pictures. Hope this helps! And, if I was totally off, my feelings won't be hurt. I'm just excited we have tech like this! I grew up at the end of 8mm home video.

[emax4]

Good point! Also, have you tried downloading them on to a computer or plugging it in to the TV set (if yours can do that), and playing it back to see if those artifacts are still there?