Converting .mp3 audio to .flv format.
Converting MP3 Audio Files directly to Flash Video Files (.mp3 to .flv conversion) is possible and quite straightforward. It relates to users attempting to encode MP3 audio to FLV video.
Try using a media editing software or (online) conversion tool, such as SUPER or Freemake Video Converter, which should allow users to import MP3 audio and export it in FLV format.