Only natively supported audio formats work with the rewind and fast forward features. You can rewind or fast forward with the following audio formats:

• MP3
• FLAC (Free Lossless Audio Codec)
• OGG (Ogg Vorbis)
• WAV/AIFF (Waveform Audio Format /Audio Interchange File Format)
• WMA CBR and WMA VBR (Windows Media Audio Constant Bitrate Variable Bitrate)

NOTE: The WAV format is transcoded to FLAC on the fly in order to save network bandwidth. In order to seek through these files, you need to disable the WAV to FLAC (built in) rule in SqueezeCenter > Server Settings > File Types.