I am using the code given in the example section "Full Duplex Audio Example 2.0". I am using PCM16 instead of given 4 types used there. After getting the recorded the in BufferToBeEmptied I find that it is stored in 8 bit CMMFBuffer (I am not sure whether it is 8 bit or not). Then coppied to CMMFDataBuffer which is 8 bit sure. Then if i use speex it want 16 bit for encoding. If I give 8 bit as input then it should work. Then I want to decode. Speex again gives decoded output of 16 bits. This time the CMMFDataBuffer can not take 16 bits for playing. So this is the problem I am facing. It would be better if I could use 16 bit buffer in both BufferToBeEmptied and BufferToBeFilled for storing and playing data that would be more convenient to go along with speex.