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Diffstat (limited to 'drivers/staging/echo/oslec.h')
-rw-r--r-- | drivers/staging/echo/oslec.h | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/drivers/staging/echo/oslec.h b/drivers/staging/echo/oslec.h new file mode 100644 index 00000000000..bad852328a2 --- /dev/null +++ b/drivers/staging/echo/oslec.h @@ -0,0 +1,86 @@ +/* + * 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 */ |