ffmpeg Command To convert the audio to mp2

ffmpeg Command To convert the audio to mp2 :
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ffmpeg -i "D:\Media\Vel1.mpg" -vn -acodec mp2 -ac 1 -ar 22050 -ab 64k "D:\Media\vel1.mp2"

while opening the MP2 file in aGraphEdit , I got the following :

Vel1.mp2 -> MPEG-1 Stream Splitter (Audio)-> MPEG Audio Decoder -> Default Directsound Device.

By Default all the filters are available in Dshow as In-built.