visual c++ - to capture the buffer of a microphone -

i creating program record microphone audio , convert mp3 using directshow api in visual c++. there no built in filter convert convert audio mpeg layer 3 i.e. mp3 want send mic buffer external library called lame , convert data in mp3 , can write file using file writer. problem dont know how access buffer of microphone , please me new in directshow programming..

or tell me other way it

if want distribute application suggest use sample grabber instead of lame directshow encoder filter. avoid filter registration need handle conversion logic.

regarding using lame encoder,

1. what return value of hr = poutputdevice->findpin().
2. you can give try using graphedit , check pin properties.