#! /bin/bash

# Initially, I was trying to have my filter function return both the flag and the flag's values.
# As you can see below, my value substring contained spaces, which led to the following two outcomes:
#   1) If the command is not quoted, the shell parses the output and splits the string into 4 words
#   2) If the command is quoted, word splitting is avoided and you get 1 word
# In both cases, the ffmpeg utility would fail since it's not passed valid options.
filter_flag_and_value() {
  echo "-filter_complex first second third"
}

filter_value() {
  echo "first second third"
}

parameter_info() {
  printf "Num args: %d\n" $#
  printf "<%s> " "$@"
  printf "\n"
}

# 4 positional parameters due to wordsplitting by the shell
parameter_info $(filter_flag_and_value)

# I don't think it's possible to have one function return both the flag and the value as 2 parameters.
parameter_info "$(filter_flag_and_value)"

# 2 positional parameters
parameter_info "-filter_complex" "first second third"
# 2 positional parameters since the result of the command substitution is not split thanks to the quotations
parameter_info "-filter_complex" "$(filter_value)"