[FFmpeg-user] Play Audio from PC Microphone Input with ffplay

[James Board]

Is it possible to use ffplay to play audio from the microphone input?
If so, how (I'm on a Linux PC running CentOS)?

Context: I connected the audio output of my DVR to the PC's microphone
input jack and I'm trying to play that audio through the PC's speakers.  Does that
make sense?

If this isn't possible with ffplay, what would be the correct tool to use to
do this?  Seems like it should be a common thing.