Need help for run time speaker indicator

Hello team,

We are working on speaker indicator, which is supposed to indicate
the level of volume received from VLC player. I have worked on
microphone, in microphone we can able to get the input buffer and
according to that we are able to display the level of volume. I have
gone through Microsoft sites I have found that if we link the speaker
volume with microphone volume then we can feed the speaker audio data
into microphone and get the volume level but that I can’t do for my
application.

Normally If I have data then using waveStreamCallback API, we can get
the speaker audio buffer for volume indicator. But VLC didn’t provide
any API so that we can get the audio buffer.
In vista we have core audio API that get the audio buffer from
speaker out ports and using that we can get the amplitude but in XP we
don’t have such API.

So please suggest me how can I implement this.