I'm trying to analysis darktable. I'm windows user.

I found the usage of darktable like as following on noiseprofile.c.

 usage : input.pfm [-c a1 b1]

Here, I want to know the c and a1 and b1.

Q1.What is this?

Q2.What do those mean?

Q3.How can we get information and parameters above parameters?

Q4.Can we make above 3 parameters?


  • \$\begingroup\$ vtc b/c Q is a programming question about the source code of a raw-processing program, not its use for photography. \$\endgroup\$
    – xiota
    Nov 28, 2018 at 22:54
  • 2
    \$\begingroup\$ I'm voting to close this question as off-topic because it is about C programming. \$\endgroup\$
    – scottbb
    Nov 29, 2018 at 5:49

1 Answer 1


Mild rewording of the question to follow.

You are asking about this line in the Darktable source code, and I applude that you are investigating the software at that level.

It's part of this section:

int main(int argc, char *arg[])
  if(argc < 2)
    fprintf(stderr, "usage: %s input.pfm [-c a1 b1]\n", arg[0]);
  int wd, ht;
float *input = read_pfm(arg[1], &wd, &ht);

And the fragment broadly reads "if the program is started without enought arguments, then print an error message giving the normal usage.

I think you've slightly misread the command. It should be along the lines of

./noiseprofile input.pfm

...and then an optional height and width.

I don't actually think this is a photography question (it's certainly far from a photography answer) so I'm voting to close on that basis...


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