Differentiate between error and standard terminal log with ffmpeg - nodejs

Question

I\'m using ffmpeg in node js. Both the standard terminal output and the error seems to be sent to stdout, so I don\'t know how to differentiate between error and su

Answer 1

Ffmpeg outputs all of its logging data to stderr, to leave stdout free for piping the output data to some other program or another ffmpeg instance.

When running ffmpeg as an automatic process it's often useful give the option

-loglevel error

which turns it completely mute in a normal scenario and only outputs the error data (to stderr), which is normally what you would expect from a command-line program.