Am 14.01.2019 um 09:48 schrieb Paul B Mahol:
On 1/14/19, Michael Koch <[email protected]> wrote:
Am 14.01.2019 um 08:40 schrieb Michael Koch:
Am 14.01.2019 um 07:28 schrieb Michael Koch:
When I create a color-look-up-table with this command line, the
result is a 512x512 clut saved as 16-bit PNG. It works as expected
and I checked that the top left pixel is black (R=0, G=0, B=0) and
the bottom right pixel is white (R=65026, G=65026, B=65026).
c:\ffmpeg\ffmpeg -f lavfi -i haldclutsrc=8 -frames 1 -pix_fmt rgb48be
-y clut.png
In the next example I wanted to extract one frame from a video,
overlay the clut in the top left corner, and save it as 16-bit PNG. I
need 16-bit PNG because my video is 10-bit. At first glimpse the
result looks good, but a closer examination finds that the top left
pixel is not pure black, it's R=0, G=1285, B=0, and the bottom right
pixel of the clut (at coordinates 511,511) is not pure white, it's
R=65535, G=63736, B=65535. Why are the colors wrong?
c:\ffmpeg\ffmpeg -ss 5 -i P1000099.mov -f lavfi -i haldclutsrc=8
-filter_complex overlay -frames 1 -pix_fmt rgb48be -y
Image_with_CLUT.png
I found a solution myself: overlay=format=rgb
But the output of the overlay filter seems to be RGB24. Is it possible
to get RGB48 out of the overlay filter? Or is there any other filter for
overlaying two RGB48 images?
Try maskedmerge filter with gbrp16 pixel format.
In the meantime a found this solution with the xstack filter:
c:\ffmpeg\ffmpeg -ss 5 -i P1000099.mov -f lavfi -i haldclutsrc=8
-filter_complex
"[1]format=pix_fmts=rgb48be[a];[a][0]xstack=inputs=2:layout=0_0|w0_0"
-frames 1 -y Image_with_CLUT.png
It's not an overlay but a horizontal stack, but that doesn't care. It's
only important that I have the clut and the picture combined in one
16-bit picture, so that they can be processed simultaneously. By the way
xstack is much better than hstack because it accepts pictures of
different height. Problem solved!
Thanks,
Michael
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