Regardless of the file output of ffmpeg, the script considers it a success

[vorwd]

As long as a the script completes this line:

temp_output_file="${temp_directory}/${filename}-AC2.${extension}"

it seems that it will consider ffmpeg a success, as it has added the file to the $temp_directory, even if it's zero sized and not successfully converted video file.

It will then output this line:

if [ $? -eq 0 ]; then
  echo -e "\n"
  echo "ffmpeg conversion successful. Temp output: $temp_output_file"
  echo "Initiating ffprobe on -AC2 file..."

and move on to the ffprobe-AC2, which results in an error (obviously, as there is no data to probe)

Impact is that the file didn't actually succeed and will end up moving a blank file to the $target_directory. Annoying on its own, but a much bigger oversight If in future iterations, the user wanted to implement an automation for deletion on the original file if a -AC2 ends up in the $target_directory.