Convert flac to aac with ffmpeg

I write this so I don't forget (Original Superuser thread)

• Install ffmpeg with libfaac support

  brew reinstall ffmpeg --with-faac;
  

• Convert them

  cd flac_directory
  for f in *.flac; do ffmpeg -i "$f" -acodec libfaac -aq 400 "${f%flac}m4a"; done
  

Certain files will throw an error: [libx264 @ 0x2f08120] height not divisible by 2 (500x489) In such case adding the following option did the trick for me:

-vf "scale=640:-2"

Taken from Stackoverflow - Maintaining ffmpeg aspect ratio