BobDiaz
Well-Known Member
Is there a way (for dev) to improve the graining with a firmware somehow?
Can you also explain why the frames at night are smeared? At day time, even when im driving 150KM/h the frames are perfectly sharp, but at night every movement smeard across the frame. In still cameras its because of longer exposure times at night. Why does it happen in the Mobius? Anything that can be done to improve it?
I could write a whole book about compression. (Just joking around)
Without going into a lot of technical details, the image is broken into little boxes, like an 8 x 8 pixel area. The exact value of each pixel is lost in the compression software, but the relative values between each pixel in the box is preserved as closely as possible, but it may be a bit off relative to the other pixels, but it's close. While the exact brightness is lost in compression, the fine details are preserved unless the compression is VERY excessive. Compression noise in video look like little boxes that change. MPEG-2 used an 8x8 area, but MPEG-4 allowed for different sized boxes. The "dancing boxes" first appear in solid colored areas with very little detail, not as a smearing of detail.
I've seen the smear in the movement in the night shots and to me it looks like a slow shutter speed. The camera must record under a wide range of lighting conditions and needs to adjust the shutter speed of the camera to adapt to the light. In bright light, many video cameras use a very short shutter, like 1/2000 of a second to capture the image. As the light drops off, the shutter speed must be longer to have a proper exposure. It is possible to increase the gain in the video amplifier to offset the loss of light, BUT as the gain increases, the background noise in the image chip is also amplified too. Some DSP (Digital Signal Processing) can be applied to the signal before compression to help reduce the noise, but because of the random nature of the noise, it's not easily performed. Most of the approaches I've seen generate a loss in sharpness.
I'm not sure how Panasonic pulled it off with their AG-AC90 video camera. This is NOT a car camera, but a camera for profession video production. Increases gain always results in increased noise, but on their AG-AC90, they have kept the noise way down, even at high gain levels.
The technology is always getting better and better, but for the near future, there's not a whole lot at the price points we are looking at. However, 10 years from now may be another story...