[Speex-dev] Size of each block in a circular buffer and the sample rate

[Kevin Jenkins]

int frameSize;
speex_encoder_ctl(enc_state, SPEEX_GET_FRAME_SIZE, &frameSize);

Is frameSize in bytes?  If not, what unit is it in?  I need to know so I 
know how big to make each element in my circular buffer.

Also, do I need to call

speex_encoder_ctl( enc_state, SPEEX_SET_SAMPLING_RATE, &sampleRate );

Depending on sample rate I record my audio in?  If not, is there any 
benefit to setting the sample rate, such as reduced bandwidth?