Speex dev - Sep 2014 - Speex_echo_cancellation() always same output

Hi all,
I have been trying to impelement echo cancellation on STM32F4 Discovery board
(having ARM based uC).In my project, I simply initialized the echo_state by
speex_echo_state_init() by using frame_size 160, filter_length 800 (at 8kHz
Sampling rate.) Then, I simply used speex_echo_cancellation() function in where
i am getting sound. However, I have recently realised that output_frame has been
always same without any relation with input_frame and echo_frame.
What can be wrong in my project? Any help will be appreciated.
Best regards,   		 	   		  
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