Free apps support downloading YouTube music as MP3 with a bitrate of up to 128 Kbps. With the Paid app, you can convert songs on YouTube to MP3 with a bitrate of up to 320 Kbps. Some apps also support the Advanced Audio Coding (AAC) codec, which offers even better quality than MP3 at the same bitrate, or Vorbis, which is technologically superior to MP3 at 192 Kbps.