Thu Oct 11 06:47:15 2012

Asterisk developer's documentation


dsp.h

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00001 /*
00002  * Asterisk -- An open source telephony toolkit.
00003  *
00004  * Copyright (C) 1999 - 2005, Digium, Inc.
00005  *
00006  * Mark Spencer <markster@digium.com>
00007  *
00008  * See http://www.asterisk.org for more information about
00009  * the Asterisk project. Please do not directly contact
00010  * any of the maintainers of this project for assistance;
00011  * the project provides a web site, mailing lists and IRC
00012  * channels for your use.
00013  *
00014  * This program is free software, distributed under the terms of
00015  * the GNU General Public License Version 2. See the LICENSE file
00016  * at the top of the source tree.
00017  */
00018 
00019 /*! \file
00020  * \brief Convenient Signal Processing routines
00021  */
00022 
00023 #ifndef _ASTERISK_DSP_H
00024 #define _ASTERISK_DSP_H
00025 
00026 #define DSP_FEATURE_SILENCE_SUPPRESS   (1 << 0)
00027 #define DSP_FEATURE_BUSY_DETECT     (1 << 1)
00028 #define DSP_FEATURE_DIGIT_DETECT (1 << 3)
00029 #define DSP_FEATURE_FAX_DETECT      (1 << 4)
00030 
00031 #define  DSP_DIGITMODE_DTMF         0           /*!< Detect DTMF digits */
00032 #define DSP_DIGITMODE_MF         1           /*!< Detect MF digits */
00033 
00034 #define DSP_DIGITMODE_NOQUELCH      (1 << 8)    /*!< Do not quelch DTMF from in-band */
00035 #define DSP_DIGITMODE_MUTECONF      (1 << 9)    /*!< Mute conference */
00036 #define DSP_DIGITMODE_MUTEMAX    (1 << 10)      /*!< Delay audio by a frame to try to extra quelch */
00037 #define DSP_DIGITMODE_RELAXDTMF     (1 << 11)      /*!< "Radio" mode (relaxed DTMF) */
00038 
00039 #define DSP_PROGRESS_TALK     (1 << 16)      /*!< Enable talk detection */
00040 #define DSP_PROGRESS_RINGING     (1 << 17)      /*!< Enable calling tone detection */
00041 #define DSP_PROGRESS_BUSY     (1 << 18)      /*!< Enable busy tone detection */
00042 #define DSP_PROGRESS_CONGESTION     (1 << 19)      /*!< Enable congestion tone detection */
00043 #define DSP_FEATURE_CALL_PROGRESS   (DSP_PROGRESS_TALK | DSP_PROGRESS_RINGING | DSP_PROGRESS_BUSY | DSP_PROGRESS_CONGESTION)
00044 #define DSP_FEATURE_WAITDIALTONE (1 << 20)      /*!< Enable dial tone detection */
00045 
00046 #define DSP_FAXMODE_DETECT_CNG   (1 << 0)
00047 #define DSP_FAXMODE_DETECT_CED   (1 << 1)
00048 #define DSP_FAXMODE_DETECT_ALL   (DSP_FAXMODE_DETECT_CNG | DSP_FAXMODE_DETECT_CED)
00049 
00050 #define DSP_TONE_STATE_SILENCE  0
00051 #define DSP_TONE_STATE_RINGING  1
00052 #define DSP_TONE_STATE_DIALTONE 2
00053 #define DSP_TONE_STATE_TALKING  3
00054 #define DSP_TONE_STATE_BUSY     4
00055 #define DSP_TONE_STATE_SPECIAL1  5
00056 #define DSP_TONE_STATE_SPECIAL2 6
00057 #define DSP_TONE_STATE_SPECIAL3 7
00058 #define DSP_TONE_STATE_HUNGUP    8
00059 
00060 struct ast_dsp;
00061 
00062 enum threshold {
00063    /* Array offsets */
00064    THRESHOLD_SILENCE = 0,
00065    /* Always the last */
00066    THRESHOLD_MAX = 1,
00067 };
00068 
00069 struct ast_dsp *ast_dsp_new(void);
00070 void ast_dsp_free(struct ast_dsp *dsp);
00071 
00072 /*! \brief Set threshold value for silence */
00073 void ast_dsp_set_threshold(struct ast_dsp *dsp, int threshold);
00074 
00075 /*! \brief Set number of required cadences for busy */
00076 void ast_dsp_set_busy_count(struct ast_dsp *dsp, int cadences);
00077 
00078 /*! \brief Set expected lengths of the busy tone */
00079 void ast_dsp_set_busy_pattern(struct ast_dsp *dsp, int tonelength, int quietlength);
00080 
00081 /*! \brief Scans for progress indication in audio */
00082 int ast_dsp_call_progress(struct ast_dsp *dsp, struct ast_frame *inf);
00083 
00084 /*! \brief Set zone for doing progress detection */
00085 int ast_dsp_set_call_progress_zone(struct ast_dsp *dsp, char *zone);
00086 
00087 /*! \brief Return AST_FRAME_NULL frames when there is silence, AST_FRAME_BUSY on
00088    busies, and call progress, all dependent upon which features are enabled */
00089 struct ast_frame *ast_dsp_process(struct ast_channel *chan, struct ast_dsp *dsp, struct ast_frame *inf);
00090 
00091 /*! \brief Return non-zero if this is silence.  Updates "totalsilence" with the total
00092    number of seconds of silence  */
00093 int ast_dsp_silence(struct ast_dsp *dsp, struct ast_frame *f, int *totalsilence);
00094 
00095 /*!
00096  * \brief Return non-zero if this is noise.  Updates "totalnoise" with the total
00097  * number of seconds of noise
00098  * \since 1.6.1
00099  */
00100 int ast_dsp_noise(struct ast_dsp *dsp, struct ast_frame *f, int *totalnoise);
00101 
00102 /*! \brief Return non-zero if historically this should be a busy, request that
00103   ast_dsp_silence has already been called */
00104 int ast_dsp_busydetect(struct ast_dsp *dsp);
00105 
00106 /*! \brief Return non-zero if DTMF hit was found */
00107 int ast_dsp_digitdetect(struct ast_dsp *dsp, struct ast_frame *f);
00108 
00109 /*! \brief Reset total silence count */
00110 void ast_dsp_reset(struct ast_dsp *dsp);
00111 
00112 /*! \brief Reset DTMF detector */
00113 void ast_dsp_digitreset(struct ast_dsp *dsp);
00114 
00115 /*! \brief Select feature set */
00116 void ast_dsp_set_features(struct ast_dsp *dsp, int features);
00117 
00118 /*! \brief Get pending DTMF/MF digits */
00119 int ast_dsp_getdigits(struct ast_dsp *dsp, char *buf, int max);
00120 
00121 /*! \brief Set digit mode
00122  * \version 1.6.1 renamed from ast_dsp_digitmode to ast_dsp_set_digitmode
00123  */
00124 int ast_dsp_set_digitmode(struct ast_dsp *dsp, int digitmode);
00125 
00126 /*! \brief Set fax mode */
00127 int ast_dsp_set_faxmode(struct ast_dsp *dsp, int faxmode);
00128 
00129 /*!
00130  * \brief Returns true if DSP code was muting any fragment of the last processed frame.
00131  * Muting (squelching) happens when DSP code removes DTMF/MF/generic tones from the audio
00132  * \since 1.6.1
00133  */
00134 int ast_dsp_was_muted(struct ast_dsp *dsp);
00135 
00136 /*! \brief Get tstate (Tone State) */
00137 int ast_dsp_get_tstate(struct ast_dsp *dsp);
00138 
00139 /*! \brief Get tcount (Threshold counter) */
00140 int ast_dsp_get_tcount(struct ast_dsp *dsp);
00141 
00142 /*!
00143  * \brief Get silence threshold from dsp.conf
00144  * \since 1.6.1
00145  */
00146 int ast_dsp_get_threshold_from_settings(enum threshold which);
00147 
00148 /*!
00149  * \brief Reloads dsp settings from dsp.conf
00150  * \since 1.6.1
00151  */
00152 int ast_dsp_reload(void);
00153 
00154 /*!
00155  * \brief Load dsp settings from dsp.conf
00156  * \since 1.6.1
00157  */
00158 int ast_dsp_init(void);
00159 
00160 /*!
00161  * \brief Hint that a frame from a dsp was freed
00162  *
00163  * This is called from ast_frame_free if AST_FRFLAG_FROM_DSP is set. This occurs
00164  * because it is possible for the dsp to be freed while someone still holds a reference
00165  * to the frame that is in that dsp. This has been known to happen when the dsp on a DAHDI
00166  * channel detects a busy signal. The channel is hung up, and the application that read the
00167  * frame to begin with still has a reference to the frame.
00168  *
00169  * \return nothing
00170  */
00171 void ast_dsp_frame_freed(struct ast_frame *fr);
00172 #endif /* _ASTERISK_DSP_H */

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