| /* |
| * Copyright (c) 2011 The WebRTC project authors. All Rights Reserved. |
| * |
| * Use of this source code is governed by a BSD-style license |
| * that can be found in the LICENSE file in the root of the source |
| * tree. An additional intellectual property rights grant can be found |
| * in the file PATENTS. All contributing project authors may |
| * be found in the AUTHORS file in the root of the source tree. |
| */ |
| |
| /* |
| * This file contains the DTMF tone generator and its parameters. |
| * |
| * A sinusoid is generated using the recursive oscillator model |
| * |
| * y[n] = sin(w*n + phi) = 2*cos(w) * y[n-1] - y[n-2] |
| * = a * y[n-1] - y[n-2] |
| * |
| * initialized with |
| * y[-2] = 0 |
| * y[-1] = sin(w) |
| * |
| * A DTMF signal is a combination of two sinusoids, depending |
| * on which event is sent (i.e, which key is pressed). The following |
| * table maps each key (event codes in parentheses) into two tones: |
| * |
| * 1209 Hz 1336 Hz 1477 Hz 1633 Hz |
| * 697 Hz 1 (ev. 1) 2 (ev. 2) 3 (ev. 3) A (ev. 12) |
| * 770 Hz 4 (ev. 4) 5 (ev. 5) 6 (ev. 6) B (ev. 13) |
| * 852 Hz 7 (ev. 7) 8 (ev. 8) 9 (ev. 9) C (ev. 14) |
| * 941 Hz * (ev. 10) 0 (ev. 0) # (ev. 11) D (ev. 15) |
| * |
| * The two tones are added to form the DTMF signal. |
| * |
| */ |
| |
| #include "dtmf_tonegen.h" |
| |
| #include "signal_processing_library.h" |
| |
| #include "neteq_error_codes.h" |
| |
| #ifdef NETEQ_ATEVENT_DECODE |
| /* Must compile NetEQ with DTMF support to enable the functionality */ |
| |
| /*******************/ |
| /* Constant tables */ |
| /*******************/ |
| |
| /* |
| * All tables corresponding to the oscillator model are organized so that |
| * the coefficients for a specific frequency is found in the same position |
| * in every table. The positions for the tones follow this layout: |
| * |
| * dummyVector[8] = |
| * { |
| * 697 Hz, 770 Hz, 852 Hz, 941 Hz, |
| * 1209 Hz, 1336 Hz, 1477 Hz, 1633 Hz |
| * }; |
| */ |
| |
| /* |
| * Tables for the constant a = 2*cos(w) = 2*cos(2*pi*f/fs) |
| * in the oscillator model, for 8, 16, 32 and 48 kHz sample rate. |
| * Table values in Q14. |
| */ |
| |
| const WebRtc_Word16 WebRtcNetEQ_dtfm_aTbl8Khz[8] = |
| { |
| 27980, 26956, 25701, 24219, |
| 19073, 16325, 13085, 9315 |
| }; |
| |
| #ifdef NETEQ_WIDEBAND |
| const WebRtc_Word16 WebRtcNetEQ_dtfm_aTbl16Khz[8]= |
| { |
| 31548, 31281, 30951, 30556, |
| 29144, 28361, 27409, 26258 |
| }; |
| #endif |
| |
| #ifdef NETEQ_32KHZ_WIDEBAND |
| const WebRtc_Word16 WebRtcNetEQ_dtfm_aTbl32Khz[8]= |
| { |
| 32462, 32394, 32311, 32210, |
| 31849, 31647, 31400, 31098 |
| }; |
| #endif |
| |
| #ifdef NETEQ_48KHZ_WIDEBAND |
| const WebRtc_Word16 WebRtcNetEQ_dtfm_aTbl48Khz[8]= |
| { |
| 32632, 32602, 32564, 32520, |
| 32359, 32268, 32157, 32022 |
| }; |
| #endif |
| |
| /* |
| * Initialization values y[-1] = sin(w) = sin(2*pi*f/fs), for 8, 16, 32 and 48 kHz sample rate. |
| * Table values in Q14. |
| */ |
| |
| const WebRtc_Word16 WebRtcNetEQ_dtfm_yInitTab8Khz[8] = |
| { |
| 8528, 9315, 10163, 11036, |
| 13323, 14206,15021, 15708 |
| }; |
| |
| #ifdef NETEQ_WIDEBAND |
| const WebRtc_Word16 WebRtcNetEQ_dtfm_yInitTab16Khz[8]= |
| { |
| 4429, 4879, 5380, 5918, |
| 7490, 8207, 8979, 9801 |
| }; |
| #endif |
| |
| #ifdef NETEQ_32KHZ_WIDEBAND |
| const WebRtc_Word16 WebRtcNetEQ_dtfm_yInitTab32Khz[8]= |
| { |
| 2235, 2468, 2728, 3010, |
| 3853, 4249, 4685, 5164 |
| }; |
| #endif |
| |
| #ifdef NETEQ_48KHZ_WIDEBAND |
| const WebRtc_Word16 WebRtcNetEQ_dtfm_yInitTab48Khz[8]= |
| { |
| 1493, 1649, 1823, 2013, |
| 2582, 2851, 3148, 3476 |
| }; |
| #endif |
| |
| /* Volume in dBm0 from 0 to -63, where 0 is the first table entry. |
| Everything below -36 is discarded, wherefore the table stops at -36. |
| Table entries are in Q14. |
| */ |
| |
| const WebRtc_Word16 WebRtcNetEQ_dtfm_dBm0[37] = { 16141, 14386, 12821, 11427, 10184, 9077, 8090, |
| 7210, 6426, 5727, 5104, 4549, 4054, 3614, |
| 3221, 2870, 2558, 2280, 2032, 1811, 1614, |
| 1439, 1282, 1143, 1018, 908, 809, 721, 643, |
| 573, 510, 455, 405, 361, 322, 287, 256 }; |
| |
| /**************************************************************************** |
| * WebRtcNetEQ_DTMFGenerate(...) |
| * |
| * Generate 10 ms DTMF signal according to input parameters. |
| * |
| * Input: |
| * - DTMFdecInst : DTMF instance |
| * - value : DTMF event number (0-15) |
| * - volume : Volume of generated signal (0-36) |
| * Volume is given in negative dBm0, i.e., volume == 0 |
| * means 0 dBm0 while volume == 36 mean -36 dBm0. |
| * - sampFreq : Sample rate in Hz |
| * |
| * Output: |
| * - signal : Pointer to vector where DTMF signal is stored; |
| * Vector must be at least sampFreq/100 samples long. |
| * - DTMFdecInst : Updated DTMF instance |
| * |
| * Return value : >0 - Number of samples written to signal |
| * : <0 - error |
| */ |
| |
| WebRtc_Word16 WebRtcNetEQ_DTMFGenerate(dtmf_tone_inst_t *DTMFdecInst, WebRtc_Word16 value, |
| WebRtc_Word16 volume, WebRtc_Word16 *signal, |
| WebRtc_UWord16 sampFreq, WebRtc_Word16 extFrameLen) |
| { |
| const WebRtc_Word16 *aTbl; /* pointer to a-coefficient table */ |
| const WebRtc_Word16 *yInitTable; /* pointer to initialization value table */ |
| WebRtc_Word16 a1 = 0; /* a-coefficient for first tone (low tone) */ |
| WebRtc_Word16 a2 = 0; /* a-coefficient for second tone (high tone) */ |
| int i; |
| int frameLen; /* number of samples to generate */ |
| int lowIndex; |
| int highIndex; |
| WebRtc_Word32 tempVal; |
| WebRtc_Word16 tempValLow; |
| WebRtc_Word16 tempValHigh; |
| |
| /* Sanity check for volume */ |
| if ((volume < 0) || (volume > 36)) |
| { |
| return DTMF_DEC_PARAMETER_ERROR; |
| } |
| |
| /* Sanity check for extFrameLen */ |
| if (extFrameLen < -1) |
| { |
| return DTMF_DEC_PARAMETER_ERROR; |
| } |
| |
| /* Select oscillator coefficient tables based on sample rate */ |
| if (sampFreq == 8000) |
| { |
| aTbl = WebRtcNetEQ_dtfm_aTbl8Khz; |
| yInitTable = WebRtcNetEQ_dtfm_yInitTab8Khz; |
| frameLen = 80; |
| #ifdef NETEQ_WIDEBAND |
| } |
| else if (sampFreq == 16000) |
| { |
| aTbl = WebRtcNetEQ_dtfm_aTbl16Khz; |
| yInitTable = WebRtcNetEQ_dtfm_yInitTab16Khz; |
| frameLen = 160; |
| #endif |
| #ifdef NETEQ_32KHZ_WIDEBAND |
| } |
| else if (sampFreq == 32000) |
| { |
| aTbl = WebRtcNetEQ_dtfm_aTbl32Khz; |
| yInitTable = WebRtcNetEQ_dtfm_yInitTab32Khz; |
| frameLen = 320; |
| #endif |
| #ifdef NETEQ_48KHZ_WIDEBAND |
| } |
| else if (sampFreq == 48000) |
| { |
| aTbl = WebRtcNetEQ_dtfm_aTbl48Khz; |
| yInitTable = WebRtcNetEQ_dtfm_yInitTab48Khz; |
| frameLen = 480; |
| #endif |
| } |
| else |
| { |
| /* unsupported sample rate */ |
| return DTMF_GEN_UNKNOWN_SAMP_FREQ; |
| } |
| |
| if (extFrameLen >= 0) |
| { |
| frameLen = extFrameLen; |
| } |
| |
| /* select low frequency based on event value */ |
| switch (value) |
| { |
| case 1: |
| case 2: |
| case 3: |
| case 12: /* first row on keypad */ |
| { |
| lowIndex = 0; /* low frequency: 697 Hz */ |
| break; |
| } |
| case 4: |
| case 5: |
| case 6: |
| case 13: /* second row on keypad */ |
| { |
| lowIndex = 1; /* low frequency: 770 Hz */ |
| break; |
| } |
| case 7: |
| case 8: |
| case 9: |
| case 14: /* third row on keypad */ |
| { |
| lowIndex = 2; /* low frequency: 852 Hz */ |
| break; |
| } |
| case 0: |
| case 10: |
| case 11: |
| case 15: /* fourth row on keypad */ |
| { |
| lowIndex = 3; /* low frequency: 941 Hz */ |
| break; |
| } |
| default: |
| { |
| return DTMF_DEC_PARAMETER_ERROR; |
| } |
| } /* end switch */ |
| |
| /* select high frequency based on event value */ |
| switch (value) |
| { |
| case 1: |
| case 4: |
| case 7: |
| case 10: /* first column on keypad */ |
| { |
| highIndex = 4; /* high frequency: 1209 Hz */ |
| break; |
| } |
| case 2: |
| case 5: |
| case 8: |
| case 0: /* second column on keypad */ |
| { |
| highIndex = 5;/* high frequency: 1336 Hz */ |
| break; |
| } |
| case 3: |
| case 6: |
| case 9: |
| case 11: /* third column on keypad */ |
| { |
| highIndex = 6;/* high frequency: 1477 Hz */ |
| break; |
| } |
| case 12: |
| case 13: |
| case 14: |
| case 15: /* fourth column on keypad (special) */ |
| { |
| highIndex = 7;/* high frequency: 1633 Hz */ |
| break; |
| } |
| default: |
| { |
| return DTMF_DEC_PARAMETER_ERROR; |
| } |
| } /* end switch */ |
| |
| /* select coefficients based on results from switches above */ |
| a1 = aTbl[lowIndex]; /* coefficient for first (low) tone */ |
| a2 = aTbl[highIndex]; /* coefficient for second (high) tone */ |
| |
| if (DTMFdecInst->reinit) |
| { |
| /* set initial values for the recursive model */ |
| DTMFdecInst->oldOutputLow[0] = yInitTable[lowIndex]; |
| DTMFdecInst->oldOutputLow[1] = 0; |
| DTMFdecInst->oldOutputHigh[0] = yInitTable[highIndex]; |
| DTMFdecInst->oldOutputHigh[1] = 0; |
| |
| /* reset reinit flag */ |
| DTMFdecInst->reinit = 0; |
| } |
| |
| /* generate signal sample by sample */ |
| for (i = 0; i < frameLen; i++) |
| { |
| |
| /* Use rescursion formula y[n] = a*y[n-1] - y[n-2] */ |
| tempValLow |
| = (WebRtc_Word16) (((WEBRTC_SPL_MUL_16_16(a1, DTMFdecInst->oldOutputLow[1]) |
| + 8192) >> 14) - DTMFdecInst->oldOutputLow[0]); |
| tempValHigh |
| = (WebRtc_Word16) (((WEBRTC_SPL_MUL_16_16(a2, DTMFdecInst->oldOutputHigh[1]) |
| + 8192) >> 14) - DTMFdecInst->oldOutputHigh[0]); |
| |
| /* Update recursion memory */ |
| DTMFdecInst->oldOutputLow[0] = DTMFdecInst->oldOutputLow[1]; |
| DTMFdecInst->oldOutputLow[1] = tempValLow; |
| DTMFdecInst->oldOutputHigh[0] = DTMFdecInst->oldOutputHigh[1]; |
| DTMFdecInst->oldOutputHigh[1] = tempValHigh; |
| |
| /* scale high tone with 32768 (15 left shifts) |
| and low tone with 23171 (3dB lower than high tone) */ |
| tempVal = WEBRTC_SPL_MUL_16_16(DTMF_AMP_LOW, tempValLow) |
| + WEBRTC_SPL_LSHIFT_W32((WebRtc_Word32)tempValHigh, 15); |
| |
| /* Norm the signal to Q14 (with proper rounding) */ |
| tempVal = (tempVal + 16384) >> 15; |
| |
| /* Scale the signal to correct dbM0 value */ |
| signal[i] = (WebRtc_Word16) WEBRTC_SPL_RSHIFT_W32( |
| (WEBRTC_SPL_MUL_16_16(tempVal, WebRtcNetEQ_dtfm_dBm0[volume]) |
| + 8192), 14); /* volume value is in Q14; use proper rounding */ |
| } |
| |
| return frameLen; |
| |
| } |
| |
| #endif /* NETEQ_ATEVENT_DECODE */ |
| |
