I want to be able to log FFMPEG processes because I am trying to work out how long a minute of video takes to convert to help with capacity planning of my video encoding server.
I found the below stuff in ffmpeg Docs. Hope this helps! :)
Reference: http://ffmpeg.org/ffmpeg.html#toc-Generic-options
‘-report’ Dump full command line and console output to a file named program-YYYYMMDD-HHMMSS.log in the current directory. This file can be useful for bug reports. It also implies -loglevel verbose.
Note: setting the environment variable FFREPORT to any value has the same effect.