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Diffstat (limited to 'src/common_audio/signal_processing_library/main/source/resample_fractional.c')
| -rw-r--r-- | src/common_audio/signal_processing_library/main/source/resample_fractional.c | 242 |
1 files changed, 242 insertions, 0 deletions
diff --git a/src/common_audio/signal_processing_library/main/source/resample_fractional.c b/src/common_audio/signal_processing_library/main/source/resample_fractional.c new file mode 100644 index 0000000000..51003d45d7 --- /dev/null +++ b/src/common_audio/signal_processing_library/main/source/resample_fractional.c @@ -0,0 +1,242 @@ +/* + * 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 resampling functions between 48, 44, 32 and 24 kHz. + * The description headers can be found in signal_processing_library.h + * + */ + +#include "signal_processing_library.h" + +// interpolation coefficients +static const WebRtc_Word16 kCoefficients48To32[2][8] = { + {778, -2050, 1087, 23285, 12903, -3783, 441, 222}, + {222, 441, -3783, 12903, 23285, 1087, -2050, 778} +}; + +static const WebRtc_Word16 kCoefficients32To24[3][8] = { + {767, -2362, 2434, 24406, 10620, -3838, 721, 90}, + {386, -381, -2646, 19062, 19062, -2646, -381, 386}, + {90, 721, -3838, 10620, 24406, 2434, -2362, 767} +}; + +static const WebRtc_Word16 kCoefficients44To32[4][9] = { + {117, -669, 2245, -6183, 26267, 13529, -3245, 845, -138}, + {-101, 612, -2283, 8532, 29790, -5138, 1789, -524, 91}, + {50, -292, 1016, -3064, 32010, 3933, -1147, 315, -53}, + {-156, 974, -3863, 18603, 21691, -6246, 2353, -712, 126} +}; + +// Resampling ratio: 2/3 +// input: WebRtc_Word32 (normalized, not saturated) :: size 3 * K +// output: WebRtc_Word32 (shifted 15 positions to the left, + offset 16384) :: size 2 * K +// K: number of blocks + +void WebRtcSpl_Resample48khzTo32khz(const WebRtc_Word32 *In, WebRtc_Word32 *Out, + const WebRtc_Word32 K) +{ + ///////////////////////////////////////////////////////////// + // Filter operation: + // + // Perform resampling (3 input samples -> 2 output samples); + // process in sub blocks of size 3 samples. + WebRtc_Word32 tmp; + WebRtc_Word32 m; + + for (m = 0; m < K; m++) + { + tmp = 1 << 14; + tmp += kCoefficients48To32[0][0] * In[0]; + tmp += kCoefficients48To32[0][1] * In[1]; + tmp += kCoefficients48To32[0][2] * In[2]; + tmp += kCoefficients48To32[0][3] * In[3]; + tmp += kCoefficients48To32[0][4] * In[4]; + tmp += kCoefficients48To32[0][5] * In[5]; + tmp += kCoefficients48To32[0][6] * In[6]; + tmp += kCoefficients48To32[0][7] * In[7]; + Out[0] = tmp; + + tmp = 1 << 14; + tmp += kCoefficients48To32[1][0] * In[1]; + tmp += kCoefficients48To32[1][1] * In[2]; + tmp += kCoefficients48To32[1][2] * In[3]; + tmp += kCoefficients48To32[1][3] * In[4]; + tmp += kCoefficients48To32[1][4] * In[5]; + tmp += kCoefficients48To32[1][5] * In[6]; + tmp += kCoefficients48To32[1][6] * In[7]; + tmp += kCoefficients48To32[1][7] * In[8]; + Out[1] = tmp; + + // update pointers + In += 3; + Out += 2; + } +} + +// Resampling ratio: 3/4 +// input: WebRtc_Word32 (normalized, not saturated) :: size 4 * K +// output: WebRtc_Word32 (shifted 15 positions to the left, + offset 16384) :: size 3 * K +// K: number of blocks + +void WebRtcSpl_Resample32khzTo24khz(const WebRtc_Word32 *In, WebRtc_Word32 *Out, + const WebRtc_Word32 K) +{ + ///////////////////////////////////////////////////////////// + // Filter operation: + // + // Perform resampling (4 input samples -> 3 output samples); + // process in sub blocks of size 4 samples. + WebRtc_Word32 m; + WebRtc_Word32 tmp; + + for (m = 0; m < K; m++) + { + tmp = 1 << 14; + tmp += kCoefficients32To24[0][0] * In[0]; + tmp += kCoefficients32To24[0][1] * In[1]; + tmp += kCoefficients32To24[0][2] * In[2]; + tmp += kCoefficients32To24[0][3] * In[3]; + tmp += kCoefficients32To24[0][4] * In[4]; + tmp += kCoefficients32To24[0][5] * In[5]; + tmp += kCoefficients32To24[0][6] * In[6]; + tmp += kCoefficients32To24[0][7] * In[7]; + Out[0] = tmp; + + tmp = 1 << 14; + tmp += kCoefficients32To24[1][0] * In[1]; + tmp += kCoefficients32To24[1][1] * In[2]; + tmp += kCoefficients32To24[1][2] * In[3]; + tmp += kCoefficients32To24[1][3] * In[4]; + tmp += kCoefficients32To24[1][4] * In[5]; + tmp += kCoefficients32To24[1][5] * In[6]; + tmp += kCoefficients32To24[1][6] * In[7]; + tmp += kCoefficients32To24[1][7] * In[8]; + Out[1] = tmp; + + tmp = 1 << 14; + tmp += kCoefficients32To24[2][0] * In[2]; + tmp += kCoefficients32To24[2][1] * In[3]; + tmp += kCoefficients32To24[2][2] * In[4]; + tmp += kCoefficients32To24[2][3] * In[5]; + tmp += kCoefficients32To24[2][4] * In[6]; + tmp += kCoefficients32To24[2][5] * In[7]; + tmp += kCoefficients32To24[2][6] * In[8]; + tmp += kCoefficients32To24[2][7] * In[9]; + Out[2] = tmp; + + // update pointers + In += 4; + Out += 3; + } +} + +// +// fractional resampling filters +// Fout = 11/16 * Fin +// Fout = 8/11 * Fin +// + +// compute two inner-products and store them to output array +static void WebRtcSpl_ResampDotProduct(const WebRtc_Word32 *in1, const WebRtc_Word32 *in2, + const WebRtc_Word16 *coef_ptr, WebRtc_Word32 *out1, + WebRtc_Word32 *out2) +{ + WebRtc_Word32 tmp1 = 16384; + WebRtc_Word32 tmp2 = 16384; + WebRtc_Word16 coef; + + coef = coef_ptr[0]; + tmp1 += coef * in1[0]; + tmp2 += coef * in2[-0]; + + coef = coef_ptr[1]; + tmp1 += coef * in1[1]; + tmp2 += coef * in2[-1]; + + coef = coef_ptr[2]; + tmp1 += coef * in1[2]; + tmp2 += coef * in2[-2]; + + coef = coef_ptr[3]; + tmp1 += coef * in1[3]; + tmp2 += coef * in2[-3]; + + coef = coef_ptr[4]; + tmp1 += coef * in1[4]; + tmp2 += coef * in2[-4]; + + coef = coef_ptr[5]; + tmp1 += coef * in1[5]; + tmp2 += coef * in2[-5]; + + coef = coef_ptr[6]; + tmp1 += coef * in1[6]; + tmp2 += coef * in2[-6]; + + coef = coef_ptr[7]; + tmp1 += coef * in1[7]; + tmp2 += coef * in2[-7]; + + coef = coef_ptr[8]; + *out1 = tmp1 + coef * in1[8]; + *out2 = tmp2 + coef * in2[-8]; +} + +// Resampling ratio: 8/11 +// input: WebRtc_Word32 (normalized, not saturated) :: size 11 * K +// output: WebRtc_Word32 (shifted 15 positions to the left, + offset 16384) :: size 8 * K +// K: number of blocks + +void WebRtcSpl_Resample44khzTo32khz(const WebRtc_Word32 *In, WebRtc_Word32 *Out, + const WebRtc_Word32 K) +{ + ///////////////////////////////////////////////////////////// + // Filter operation: + // + // Perform resampling (11 input samples -> 8 output samples); + // process in sub blocks of size 11 samples. + WebRtc_Word32 tmp; + WebRtc_Word32 m; + + for (m = 0; m < K; m++) + { + tmp = 1 << 14; + + // first output sample + Out[0] = ((WebRtc_Word32)In[3] << 15) + tmp; + + // sum and accumulate filter coefficients and input samples + tmp += kCoefficients44To32[3][0] * In[5]; + tmp += kCoefficients44To32[3][1] * In[6]; + tmp += kCoefficients44To32[3][2] * In[7]; + tmp += kCoefficients44To32[3][3] * In[8]; + tmp += kCoefficients44To32[3][4] * In[9]; + tmp += kCoefficients44To32[3][5] * In[10]; + tmp += kCoefficients44To32[3][6] * In[11]; + tmp += kCoefficients44To32[3][7] * In[12]; + tmp += kCoefficients44To32[3][8] * In[13]; + Out[4] = tmp; + + // sum and accumulate filter coefficients and input samples + WebRtcSpl_ResampDotProduct(&In[0], &In[17], kCoefficients44To32[0], &Out[1], &Out[7]); + + // sum and accumulate filter coefficients and input samples + WebRtcSpl_ResampDotProduct(&In[2], &In[15], kCoefficients44To32[1], &Out[2], &Out[6]); + + // sum and accumulate filter coefficients and input samples + WebRtcSpl_ResampDotProduct(&In[3], &In[14], kCoefficients44To32[2], &Out[3], &Out[5]); + + // update pointers + In += 11; + Out += 8; + } +} |