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Since the resolution of the 5DMkII is so high I wonder if Canon isn't demosaicing the bayer filter but rather doing simple arithmetic weighted averaging, or something similar, to cut down on the enormous CPU overhead required to demosaic 21MP at 30fps and then remap to 1920x1080 and finally compress to H.264. That's quite a bit of work for the electronics in the camera!
By doing something simple like taking each 2x2 filter pattern and making it a pixel by using a weighted average of the 2 green, 1 blue, and 1 red sensor elements they can easily obtain a value for the entire 2x2 element.
Since the raw resolution of the sensor is 5616x3744 the resolution obtained from a simple method like this would be 2808x1872. From here the output could either be cropped to 1920x1080 or remapped to that resolution. Since it appears camera does not work in crop mode when shooting video it appears as though if indeed Canon is doing what I suspect then they are remapping.
It'll be interesting to eventually get the tech details on this as it's pretty amazing they are doing it in a prosumer dSLR.
- Mark
By doing something simple like taking each 2x2 filter pattern and making it a pixel by using a weighted average of the 2 green, 1 blue, and 1 red sensor elements they can easily obtain a value for the entire 2x2 element.
Since the raw resolution of the sensor is 5616x3744 the resolution obtained from a simple method like this would be 2808x1872. From here the output could either be cropped to 1920x1080 or remapped to that resolution. Since it appears camera does not work in crop mode when shooting video it appears as though if indeed Canon is doing what I suspect then they are remapping.
It'll be interesting to eventually get the tech details on this as it's pretty amazing they are doing it in a prosumer dSLR.
- Mark
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