와우자는 미디어 파일의 유형에 따라 접두어를 지정하는데 기준은 아래와 같다.

  * flv: FLV (Flash Video) This is the default media type so the file name prefix and extension can be omitted.
Example: "flv:mycoolvideo.flv"

  * mp4: MP4 (QuickTime container) .mp4, .f4v, .mov, .m4a, .m4v, .mp4a, .mp4v, .3gp, and .3g2).
Example: "mp4:mycoolvideo.mov"

  * mp3: MP3 (.mp3)
Example: "mp3:mycoolsong.mp3"

  * smil: SMIL (XML file used to configure adaptive bitrate streams - .smil).
  * id3: MP3 file (returns only ID3 tag information) 
  * ngrp: Named Group (for adaptive-bitrate delivery)
  * amlst: API-based MediaList (for adaptive bitrate delivery)