Yellow_
18th December 2011, 12:36
Looking for comments on the following two images extracted from native video files from two cameras and then a bit plane extracted from each.
http://www.yellowspace.webspace.virginmedia.com/C300-Tram_8-adj.png
http://www.yellowspace.webspace.virginmedia.com/T2i_MOV_8-adj.png
A Canon C300 '4k' $20,000 camera shooting XDCAM 422 in an MXF source files from here: http://ninofilm.net/blog/2011/12/09/canon-eos-c300-review-short-film/ which according to sources like dvinfo.net : http://www.dvinfo.net/article/acquisition/canon-eos/canon-usa-announces-cinema-eos-c300-and-eos-c300-pl-cameras.html
"The sensor has a resolution of 2,160 pixels tall by 3,840 pixels wide, which qualifies as native 4K.
...every four pixels (two green, one red, and one blue) are sampled for each final output pixel. In other words, color is assembled the same way as a traditional three-chip sensor block… two megapixels of red, two megapixels of blue and four megapixels of green (twice as much green as red or blue, since green carries the luminance info). Each primary color sampling off of the sensor is native 1920×1080, each color value alone is equal to the final output resolution. Canon claims that the processed signal has 1,000 lines of TV resolution, and the moire, diagonal line stair-stepping and other artifacts are greatly reduced in this chip compared to HD-DSLR cameras."
The interesting thing is the double luma and the description of the C300 giving a 'organic' pleasing grain, attractive digital noise :-), in the eye of the beyolder. :-)
The second image is the same bit plane level but extracted from a 'similar' scene in terms of exposure, colour and dof, but from a $500 Canon T2i / 550D DSLR h264AVC at 1920x1088.
FFmpegSource2 and ConvertToRGB PC levels were used to extract the image frames. Imagemagick was used for the bit plane extraction. Using Convert C300-Tram.png -fx '(int(u*255)&8)/255' C300-Tram_8.png and then Gimp to wack up the contrast and brightness by 127 to see the bit plane.
What interests me, :-) is the chequerboard pattern clearly seen on many of 'macroblocks?' in the bit planes from the C300 source, what could this be, it seems indiscriminate, is this bayer pattern? Ordered dithering? Any ideas?
It's not seen in the T2i / 550D source and assume this is a by product of the way the C300 sensor data is being put into a 1920x1080 frame.
Second query is probably going to be considered as pointless but with regard to 'cretinsealpes' Dither tools and LSB/MSB stacking and the possibility of taking the T2i/550D 1920x1088 h264 source up to 16bit by LSB/MSB, upsizing the luma to double res, maybe sharpening the luma somewhat, maybe sharpening by local contrast adjustment or USM instead, add a noise / grain layer via GrainFactory4 or Dither tools own grain functions or a dithering method that would allow further processing, all to bolster the luma plane, then resize back to 1920x1088 and add back chroma including upsampling of chroma to 4:2:2 and encode out to something like lossless 10bit h264 or similar for grading.
http://www.yellowspace.webspace.virginmedia.com/C300-Tram_8-adj.png
http://www.yellowspace.webspace.virginmedia.com/T2i_MOV_8-adj.png
A Canon C300 '4k' $20,000 camera shooting XDCAM 422 in an MXF source files from here: http://ninofilm.net/blog/2011/12/09/canon-eos-c300-review-short-film/ which according to sources like dvinfo.net : http://www.dvinfo.net/article/acquisition/canon-eos/canon-usa-announces-cinema-eos-c300-and-eos-c300-pl-cameras.html
"The sensor has a resolution of 2,160 pixels tall by 3,840 pixels wide, which qualifies as native 4K.
...every four pixels (two green, one red, and one blue) are sampled for each final output pixel. In other words, color is assembled the same way as a traditional three-chip sensor block… two megapixels of red, two megapixels of blue and four megapixels of green (twice as much green as red or blue, since green carries the luminance info). Each primary color sampling off of the sensor is native 1920×1080, each color value alone is equal to the final output resolution. Canon claims that the processed signal has 1,000 lines of TV resolution, and the moire, diagonal line stair-stepping and other artifacts are greatly reduced in this chip compared to HD-DSLR cameras."
The interesting thing is the double luma and the description of the C300 giving a 'organic' pleasing grain, attractive digital noise :-), in the eye of the beyolder. :-)
The second image is the same bit plane level but extracted from a 'similar' scene in terms of exposure, colour and dof, but from a $500 Canon T2i / 550D DSLR h264AVC at 1920x1088.
FFmpegSource2 and ConvertToRGB PC levels were used to extract the image frames. Imagemagick was used for the bit plane extraction. Using Convert C300-Tram.png -fx '(int(u*255)&8)/255' C300-Tram_8.png and then Gimp to wack up the contrast and brightness by 127 to see the bit plane.
What interests me, :-) is the chequerboard pattern clearly seen on many of 'macroblocks?' in the bit planes from the C300 source, what could this be, it seems indiscriminate, is this bayer pattern? Ordered dithering? Any ideas?
It's not seen in the T2i / 550D source and assume this is a by product of the way the C300 sensor data is being put into a 1920x1080 frame.
Second query is probably going to be considered as pointless but with regard to 'cretinsealpes' Dither tools and LSB/MSB stacking and the possibility of taking the T2i/550D 1920x1088 h264 source up to 16bit by LSB/MSB, upsizing the luma to double res, maybe sharpening the luma somewhat, maybe sharpening by local contrast adjustment or USM instead, add a noise / grain layer via GrainFactory4 or Dither tools own grain functions or a dithering method that would allow further processing, all to bolster the luma plane, then resize back to 1920x1088 and add back chroma including upsampling of chroma to 4:2:2 and encode out to something like lossless 10bit h264 or similar for grading.