[FFmpeg-user] Fluorescent White Balance Video Filters
astroelectronic at t-online.de
Thu Apr 21 20:36:03 EEST 2022
Am 21.04.2022 um 04:25 schrieb Roger:
>> You can make your own LUT, as described in chapter 2.28 in my book.
>> -- Extract one frame from your video.
>> -- Insert a haldclut in a corner of the image, or use xstack to attach it to
>> the side.
>> -- Use the program of your choice to correct the colors in this image. When
>> done, save it lossless as 16-bit PNG.
>> -- Use FFmpeg to separate the haldclut from the image.
>> -- Apply the LUT to the whole video.
> Sorry. I had a little difficulty with understanding the text within the
> Chapter 2.28. Just couldn't scan and understand easily. Although I thoroughly
> understand SH/Bash, the variable assignments for simple filenames also slowed
> reading, as I had to scan/reference back to the top of the page for the
> definition/intent of the variable used. Easier understanding for the reader to
> read, "input_video.ext" and "output_video.ext", or use a similar named variable
> such as $_input_video.ext and $_output_video.ext. Note: using a prefixed
> underscore within SH/Bash variables separates/isolates from any possible
> conflicts. Heard of using this syntax from the Bash mailing list when doing C
> style defines in SH/Bash. However, for the sake of easy readability for
> readers, it's probably best to use simple non-isolated variables.
My examples are for Windows batch files. For example, the line
sets the variable IN to the value P100.mov
If this variable is used in the command line, for example
ffmpeg -i %IN% -vf crop=...
then %IN% will be replaced by the filename, so that the command line for
ffmpeg -i P100.mov -vf crop=...
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