1 files changed, 86 insertions, 0 deletions
diff --git a/drivers/staging/echo/oslec.h b/drivers/staging/echo/oslec.h
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+++ b/drivers/staging/echo/oslec.h
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+/*
+ *  OSLEC - A line echo canceller.  This code is being developed
+ *          against and partially complies with G168. Using code from SpanDSP
+ *
+ * Written by Steve Underwood <steveu@coppice.org>
+ *         and David Rowe <david_at_rowetel_dot_com>
+ *
+ * Copyright (C) 2001 Steve Underwood and 2007-2008 David Rowe
+ *
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2, as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ */
+
+#ifndef __OSLEC_H
+#define __OSLEC_H
+
+/* TODO: document interface */
+
+/* Mask bits for the adaption mode */
+#define ECHO_CAN_USE_ADAPTION	0x01
+#define ECHO_CAN_USE_NLP	0x02
+#define ECHO_CAN_USE_CNG	0x04
+#define ECHO_CAN_USE_CLIP	0x08
+#define ECHO_CAN_USE_TX_HPF	0x10
+#define ECHO_CAN_USE_RX_HPF	0x20
+#define ECHO_CAN_DISABLE	0x40
+
+/*!
+    G.168 echo canceller descriptor. This defines the working state for a line
+    echo canceller.
+*/
+struct oslec_state;
+
+/*! Create a voice echo canceller context.
+    \param len The length of the canceller, in samples.
+    \return The new canceller context, or NULL if the canceller could not be created.
+*/
+struct oslec_state *oslec_create(int len, int adaption_mode);
+
+/*! Free a voice echo canceller context.
+    \param ec The echo canceller context.
+*/
+void oslec_free(struct oslec_state *ec);
+
+/*! Flush (reinitialise) a voice echo canceller context.
+    \param ec The echo canceller context.
+*/
+void oslec_flush(struct oslec_state *ec);
+
+/*! Set the adaption mode of a voice echo canceller context.
+    \param ec The echo canceller context.
+    \param adapt The mode.
+*/
+void oslec_adaption_mode(struct oslec_state *ec, int adaption_mode);
+
+void oslec_snapshot(struct oslec_state *ec);
+
+/*! Process a sample through a voice echo canceller.
+    \param ec The echo canceller context.
+    \param tx The transmitted audio sample.
+    \param rx The received audio sample.
+    \return The clean (echo cancelled) received sample.
+*/
+int16_t oslec_update(struct oslec_state *ec, int16_t tx, int16_t rx);
+
+/*! Process to high pass filter the tx signal.
+    \param ec The echo canceller context.
+    \param tx The transmitted auio sample.
+    \return The HP filtered transmit sample, send this to your D/A.
+*/
+int16_t oslec_hpf_tx(struct oslec_state *ec, int16_t tx);
+
+#endif /* __OSLEC_H */