| /* |
| ** Copyright 2003-2010, VisualOn, Inc. |
| ** |
| ** Licensed under the Apache License, Version 2.0 (the "License"); |
| ** you may not use this file except in compliance with the License. |
| ** You may obtain a copy of the License at |
| ** |
| ** http://www.apache.org/licenses/LICENSE-2.0 |
| ** |
| ** Unless required by applicable law or agreed to in writing, software |
| ** distributed under the License is distributed on an "AS IS" BASIS, |
| ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| ** See the License for the specific language governing permissions and |
| ** limitations under the License. |
| */ |
| |
| /*********************************************************************** |
| * File: decim54.c * |
| * * |
| * Description:Decimation of 16kHz signal to 12.8kHz * |
| * * |
| ************************************************************************/ |
| |
| #include "typedef.h" |
| #include "basic_op.h" |
| #include "acelp.h" |
| #include "cnst.h" |
| |
| #define FAC5 5 |
| #define DOWN_FAC 26215 /* 4/5 in Q15 */ |
| |
| #define NB_COEF_DOWN 15 |
| |
| /* Local functions */ |
| static void Down_samp( |
| Word16 * sig, /* input: signal to downsampling */ |
| Word16 * sig_d, /* output: downsampled signal */ |
| Word16 L_frame_d /* input: length of output */ |
| ); |
| |
| /* 1/5 resolution interpolation filter (in Q14) */ |
| /* -1.5dB @ 6kHz, -6dB @ 6.4kHz, -10dB @ 6.6kHz, -20dB @ 6.9kHz, -25dB @ 7kHz, -55dB @ 8kHz */ |
| |
| static Word16 fir_down1[4][30] = |
| { |
| {-5, 24, -50, 54, 0, -128, 294, -408, 344, 0, -647, 1505, -2379, 3034, 13107, 3034, -2379, 1505, -647, 0, 344, -408, |
| 294, -128, 0, 54, -50, 24, -5, 0}, |
| |
| {-6, 19, -26, 0, 77, -188, 270, -233, 0, 434, -964, 1366, -1293, 0, 12254, 6575, -2746, 1030, 0, -507, 601, -441, |
| 198, 0, -95, 99, -58, 18, 0, -1}, |
| |
| {-3, 9, 0, -41, 111, -170, 153, 0, -295, 649, -888, 770, 0, -1997, 9894, 9894, -1997, 0, 770, -888, 649, -295, 0, |
| 153, -170, 111, -41, 0, 9, -3}, |
| |
| {-1, 0, 18, -58, 99, -95, 0, 198, -441, 601, -507, 0, 1030, -2746, 6575, 12254, 0, -1293, 1366, -964, 434, 0, |
| -233, 270, -188, 77, 0, -26, 19, -6} |
| }; |
| |
| void Init_Decim_12k8( |
| Word16 mem[] /* output: memory (2*NB_COEF_DOWN) set to zeros */ |
| ) |
| { |
| Set_zero(mem, 2 * NB_COEF_DOWN); |
| return; |
| } |
| |
| void Decim_12k8( |
| Word16 sig16k[], /* input: signal to downsampling */ |
| Word16 lg, /* input: length of input */ |
| Word16 sig12k8[], /* output: decimated signal */ |
| Word16 mem[] /* in/out: memory (2*NB_COEF_DOWN) */ |
| ) |
| { |
| Word16 lg_down; |
| Word16 signal[L_FRAME16k + (2 * NB_COEF_DOWN)]; |
| |
| Copy(mem, signal, 2 * NB_COEF_DOWN); |
| |
| Copy(sig16k, signal + (2 * NB_COEF_DOWN), lg); |
| |
| lg_down = (lg * DOWN_FAC)>>15; |
| |
| Down_samp(signal + NB_COEF_DOWN, sig12k8, lg_down); |
| |
| Copy(signal + lg, mem, 2 * NB_COEF_DOWN); |
| |
| return; |
| } |
| |
| static void Down_samp( |
| Word16 * sig, /* input: signal to downsampling */ |
| Word16 * sig_d, /* output: downsampled signal */ |
| Word16 L_frame_d /* input: length of output */ |
| ) |
| { |
| Word32 i, j, frac, pos; |
| Word16 *x, *y; |
| Word32 L_sum; |
| |
| pos = 0; /* position is in Q2 -> 1/4 resolution */ |
| for (j = 0; j < L_frame_d; j++) |
| { |
| i = (pos >> 2); /* integer part */ |
| frac = pos & 3; /* fractional part */ |
| x = sig + i - NB_COEF_DOWN + 1; |
| y = (Word16 *)(fir_down1 + frac); |
| |
| L_sum = vo_mult32((*x++),(*y++)); |
| L_sum += vo_mult32((*x++),(*y++)); |
| L_sum += vo_mult32((*x++),(*y++)); |
| L_sum += vo_mult32((*x++),(*y++)); |
| L_sum += vo_mult32((*x++),(*y++)); |
| L_sum += vo_mult32((*x++),(*y++)); |
| L_sum += vo_mult32((*x++),(*y++)); |
| L_sum += vo_mult32((*x++),(*y++)); |
| L_sum += vo_mult32((*x++),(*y++)); |
| L_sum += vo_mult32((*x++),(*y++)); |
| L_sum += vo_mult32((*x++),(*y++)); |
| L_sum += vo_mult32((*x++),(*y++)); |
| L_sum += vo_mult32((*x++),(*y++)); |
| L_sum += vo_mult32((*x++),(*y++)); |
| L_sum += vo_mult32((*x++),(*y++)); |
| L_sum += vo_mult32((*x++),(*y++)); |
| L_sum += vo_mult32((*x++),(*y++)); |
| L_sum += vo_mult32((*x++),(*y++)); |
| L_sum += vo_mult32((*x++),(*y++)); |
| L_sum += vo_mult32((*x++),(*y++)); |
| L_sum += vo_mult32((*x++),(*y++)); |
| L_sum += vo_mult32((*x++),(*y++)); |
| L_sum += vo_mult32((*x++),(*y++)); |
| L_sum += vo_mult32((*x++),(*y++)); |
| L_sum += vo_mult32((*x++),(*y++)); |
| L_sum += vo_mult32((*x++),(*y++)); |
| L_sum += vo_mult32((*x++),(*y++)); |
| L_sum += vo_mult32((*x++),(*y++)); |
| L_sum += vo_mult32((*x++),(*y++)); |
| L_sum += vo_mult32((*x),(*y)); |
| |
| L_sum = L_shl2(L_sum, 2); |
| sig_d[j] = extract_h(L_add(L_sum, 0x8000)); |
| pos += FAC5; /* pos + 5/4 */ |
| } |
| return; |
| } |
| |
| |