When using dcraw I could set -c option to direct to stdout as specified at the top of the man page here:

https://www.cybercom.net/~dcoffin/dcraw/dcraw.1.html

This allowed me to write jpegs or pngs on the fly via the comand line (e.g. something like this: http://www.mutaku.com/wp/index.php/2011/02/cook-your-raw-photos-into-jpe...)

I've made the move to libraw and love the extra speed and the better results. However at the moment I'm only interacting with it via dcraw_emu and the command line. I see that -c is used for the float value here. So when I try to do something like this:

dcraw_emu -F -v -W -aexpo 1.75 0.0 -c 1 -q 9 -n 50 -m 1 -G -agreen 0.03 -o 4 -aclean 0.01 0.01 -fbdd 1 -timing -T -6 myfile.CR2| cjpeg -quality 100 -optimize -progressive > mynewfile.jpg

I just get an empty file. I've tried adding other switches such as -F (i.e. Use FILE I/O instead of streambuf) and also -T -6 so that output is a 16bit TIFF. I'm pretty sure I must be missing something obvious.

Any help here would be much appreciated as would love to convert on the fly as I did before.