Suppressing stubborn console output on system calls in Ruby

Question

I'm calling imagemagik's convert program from within ruby to convert image types. I'm redirecting both stdout and stderr to /dev/null but I'm still getting console text. It only occurs when converting FROM webp so I suspect it's output from the Ubuntu webp package.

buffer = `convert -quiet "#{temp_dir}#{tmp_image_filename}" "#{temp_dir}#{new_image_filename}" > /dev/null 2>&1`

Output:

Decoded /tmp/magick-3658rrhNn7wh4IW2. Dimensions: 580 x 300 . Format: lossy. Now saving...
Saved file /tmp/magick-3658nGuNL-bzCkRA

Is this tty output? I can't figure out how to capture and suppress it. I added the quiet attribute to convert command line but it had no affect (another reason I suspect webp is the culprit). I've tried several other tips in my stackoverflow search with system, IO, wrapping in : $(...), etc to no avail. Any help?

Thanks! Eric

Answer 1

Question was answered in the comments. I moved to Open3.capture3 using a format like below and the console text from webp is captured.

stdout, stderr, status = Open3.capture3("convert -flatten \"#{$temp_dir}#{tmp_image_filename}\" \"#{$temp_dir}#{@image_filename}\"")