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diff --git a/src/libspeex/include/speex/speex_echo.h b/src/libspeex/include/speex/speex_echo.h
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+++ b/src/libspeex/include/speex/speex_echo.h
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+/* Copyright (C) Jean-Marc Valin */
+/**
+   @file speex_echo.h
+   @brief Echo cancellation
+*/
+/*
+   Redistribution and use in source and binary forms, with or without
+   modification, are permitted provided that the following conditions are
+   met:
+
+   1. Redistributions of source code must retain the above copyright notice,
+   this list of conditions and the following disclaimer.
+
+   2. Redistributions in binary form must reproduce the above copyright
+   notice, this list of conditions and the following disclaimer in the
+   documentation and/or other materials provided with the distribution.
+
+   3. The name of the author may not be used to endorse or promote products
+   derived from this software without specific prior written permission.
+
+   THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+   IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+   OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+   DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
+   INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+   (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+   SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+   HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+   STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+   ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+   POSSIBILITY OF SUCH DAMAGE.
+*/
+
+#ifndef SPEEX_ECHO_H
+#define SPEEX_ECHO_H
+/** @defgroup SpeexEchoState SpeexEchoState: Acoustic echo canceller
+ *  This is the acoustic echo canceller module.
+ *  @{
+ */
+#include "speex/speex_types.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/** Obtain frame size used by the AEC */
+#define SPEEX_ECHO_GET_FRAME_SIZE 3
+
+/** Set sampling rate */
+#define SPEEX_ECHO_SET_SAMPLING_RATE 24
+/** Get sampling rate */
+#define SPEEX_ECHO_GET_SAMPLING_RATE 25
+
+/** Internal echo canceller state. Should never be accessed directly. */
+struct SpeexEchoState_;
+
+/** @class SpeexEchoState
+ * This holds the state of the echo canceller. You need one per channel. 
+*/
+
+/** Internal echo canceller state. Should never be accessed directly. */
+typedef struct SpeexEchoState_ SpeexEchoState;
+
+/** Creates a new echo canceller state
+ * @param frame_size Number of samples to process at one time (should correspond to 10-20 ms)
+ * @param filter_length Number of samples of echo to cancel (should generally correspond to 100-500 ms)
+ * @return Newly-created echo canceller state
+ */
+SpeexEchoState *speex_echo_state_init(int frame_size, int filter_length);
+
+/** Destroys an echo canceller state 
+ * @param st Echo canceller state
+*/
+void speex_echo_state_destroy(SpeexEchoState *st);
+
+/** Performs echo cancellation a frame, based on the audio sent to the speaker (no delay is added
+ * to playback in this form)
+ *
+ * @param st Echo canceller state
+ * @param rec Signal from the microphone (near end + far end echo)
+ * @param play Signal played to the speaker (received from far end)
+ * @param out Returns near-end signal with echo removed
+ */
+void speex_echo_cancellation(SpeexEchoState *st, const spx_int16_t *rec, const spx_int16_t *play, spx_int16_t *out);
+
+/** Performs echo cancellation a frame (deprecated) */
+void speex_echo_cancel(SpeexEchoState *st, const spx_int16_t *rec, const spx_int16_t *play, spx_int16_t *out, spx_int32_t *Yout);
+
+/** Perform echo cancellation using internal playback buffer, which is delayed by two frames
+ * to account for the delay introduced by most soundcards (but it could be off!)
+ * @param st Echo canceller state
+ * @param rec Signal from the microphone (near end + far end echo)
+ * @param out Returns near-end signal with echo removed
+*/
+void speex_echo_capture(SpeexEchoState *st, const spx_int16_t *rec, spx_int16_t *out);
+
+/** Let the echo canceller know that a frame was just queued to the soundcard
+ * @param st Echo canceller state
+ * @param play Signal played to the speaker (received from far end)
+*/
+void speex_echo_playback(SpeexEchoState *st, const spx_int16_t *play);
+
+/** Reset the echo canceller to its original state 
+ * @param st Echo canceller state
+ */
+void speex_echo_state_reset(SpeexEchoState *st);
+
+/** Used like the ioctl function to control the echo canceller parameters
+ *
+ * @param st Echo canceller state
+ * @param request ioctl-type request (one of the SPEEX_ECHO_* macros)
+ * @param ptr Data exchanged to-from function
+ * @return 0 if no error, -1 if request in unknown
+ */
+int speex_echo_ctl(SpeexEchoState *st, int request, void *ptr);
+
+#ifdef __cplusplus
+}
+#endif
+
+
+/** @}*/
+#endif