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webrtc-audio-processing/webrtc/common_audio/signal_processing/include/signal_processing_library.h
Arun Raghavan b5c48b97f6 Bump to WebRTC M131 release 
Ongoing fixes and improvements, transient suppressor is gone. Also,
dropping isac because it doesn't seem to be useful, and is just build
system deadweight now.

Upstream references:

  Version: 131.0.6778.200
  WebRTC: 79aff54b0fa9238ce3518dd9eaf9610cd6f22e82
  Chromium: 2a19506ad24af755f2a215a4c61f775393e0db42
2024-12-26 12:55:16 -05:00

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/*
* Copyright (c) 2012 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 header file includes all of the fix point signal processing library
* (SPL) function descriptions and declarations. For specific function calls,
* see bottom of file.
*/
#ifndef COMMON_AUDIO_SIGNAL_PROCESSING_INCLUDE_SIGNAL_PROCESSING_LIBRARY_H_
#define COMMON_AUDIO_SIGNAL_PROCESSING_INCLUDE_SIGNAL_PROCESSING_LIBRARY_H_
#include <string.h>
#include "common_audio/signal_processing/dot_product_with_scale.h"
// Macros specific for the fixed point implementation
#define WEBRTC_SPL_WORD16_MAX 32767
#define WEBRTC_SPL_WORD16_MIN -32768
#define WEBRTC_SPL_WORD32_MAX (int32_t)0x7fffffff
#define WEBRTC_SPL_WORD32_MIN (int32_t)0x80000000
#define WEBRTC_SPL_MAX_LPC_ORDER 14
#define WEBRTC_SPL_MIN(A, B) (A < B ? A : B) // Get min value
#define WEBRTC_SPL_MAX(A, B) (A > B ? A : B) // Get max value
// TODO(kma/bjorn): For the next two macros, investigate how to correct the code
// for inputs of a = WEBRTC_SPL_WORD16_MIN or WEBRTC_SPL_WORD32_MIN.
#define WEBRTC_SPL_ABS_W16(a) (((int16_t)a >= 0) ? ((int16_t)a) : -((int16_t)a))
#define WEBRTC_SPL_ABS_W32(a) (((int32_t)a >= 0) ? ((int32_t)a) : -((int32_t)a))
#define WEBRTC_SPL_MUL(a, b) ((int32_t)((int32_t)(a) * (int32_t)(b)))
#define WEBRTC_SPL_UMUL(a, b) ((uint32_t)((uint32_t)(a) * (uint32_t)(b)))
#define WEBRTC_SPL_UMUL_32_16(a, b) ((uint32_t)((uint32_t)(a) * (uint16_t)(b)))
#define WEBRTC_SPL_MUL_16_U16(a, b) ((int32_t)(int16_t)(a) * (uint16_t)(b))
// clang-format off
// clang-format would choose some identation
// leading to presubmit error (cpplint.py)
#ifndef WEBRTC_ARCH_ARM_V7
// For ARMv7 platforms, these are inline functions in spl_inl_armv7.h
#ifndef MIPS32_LE
// For MIPS platforms, these are inline functions in spl_inl_mips.h
#define WEBRTC_SPL_MUL_16_16(a, b) ((int32_t)(((int16_t)(a)) * ((int16_t)(b))))
#define WEBRTC_SPL_MUL_16_32_RSFT16(a, b) \
(WEBRTC_SPL_MUL_16_16(a, b >> 16) + \
((WEBRTC_SPL_MUL_16_16(a, (b & 0xffff) >> 1) + 0x4000) >> 15))
#endif
#endif
#define WEBRTC_SPL_MUL_16_32_RSFT11(a, b) \
(WEBRTC_SPL_MUL_16_16(a, (b) >> 16) * (1 << 5) + \
(((WEBRTC_SPL_MUL_16_U16(a, (uint16_t)(b)) >> 1) + 0x0200) >> 10))
#define WEBRTC_SPL_MUL_16_32_RSFT14(a, b) \
(WEBRTC_SPL_MUL_16_16(a, (b) >> 16) * (1 << 2) + \
(((WEBRTC_SPL_MUL_16_U16(a, (uint16_t)(b)) >> 1) + 0x1000) >> 13))
#define WEBRTC_SPL_MUL_16_32_RSFT15(a, b) \
((WEBRTC_SPL_MUL_16_16(a, (b) >> 16) * (1 << 1)) + \
(((WEBRTC_SPL_MUL_16_U16(a, (uint16_t)(b)) >> 1) + 0x2000) >> 14))
// clang-format on
#define WEBRTC_SPL_MUL_16_16_RSFT(a, b, c) (WEBRTC_SPL_MUL_16_16(a, b) >> (c))
#define WEBRTC_SPL_MUL_16_16_RSFT_WITH_ROUND(a, b, c) \
((WEBRTC_SPL_MUL_16_16(a, b) + ((int32_t)(((int32_t)1) << ((c)-1)))) >> (c))
// C + the 32 most significant bits of A * B
#define WEBRTC_SPL_SCALEDIFF32(A, B, C) \
(C + (B >> 16) * A + (((uint32_t)(B & 0x0000FFFF) * A) >> 16))
#define WEBRTC_SPL_SAT(a, b, c) (b > a ? a : b < c ? c : b)
// Shifting with negative numbers allowed
// Positive means left shift
#define WEBRTC_SPL_SHIFT_W32(x, c) ((c) >= 0 ? (x) * (1 << (c)) : (x) >> -(c))
// Shifting with negative numbers not allowed
// We cannot do casting here due to signed/unsigned problem
#define WEBRTC_SPL_LSHIFT_W32(x, c) ((x) << (c))
#define WEBRTC_SPL_RSHIFT_U32(x, c) ((uint32_t)(x) >> (c))
#define WEBRTC_SPL_RAND(a) ((int16_t)((((int16_t)a * 18816) >> 7) & 0x00007fff))
#ifdef __cplusplus
extern "C" {
#endif
#define WEBRTC_SPL_MEMCPY_W16(v1, v2, length) \
memcpy(v1, v2, (length) * sizeof(int16_t))
// inline functions:
#include "common_audio/signal_processing/include/spl_inl.h"
// third party math functions
#include "common_audio/third_party/spl_sqrt_floor/spl_sqrt_floor.h"
int16_t WebRtcSpl_GetScalingSquare(int16_t* in_vector,
size_t in_vector_length,
size_t times);
// Copy and set operations. Implementation in copy_set_operations.c.
// Descriptions at bottom of file.
void WebRtcSpl_MemSetW16(int16_t* vector,
int16_t set_value,
size_t vector_length);
void WebRtcSpl_MemSetW32(int32_t* vector,
int32_t set_value,
size_t vector_length);
void WebRtcSpl_MemCpyReversedOrder(int16_t* out_vector,
int16_t* in_vector,
size_t vector_length);
void WebRtcSpl_CopyFromEndW16(const int16_t* in_vector,
size_t in_vector_length,
size_t samples,
int16_t* out_vector);
void WebRtcSpl_ZerosArrayW16(int16_t* vector, size_t vector_length);
void WebRtcSpl_ZerosArrayW32(int32_t* vector, size_t vector_length);
// End: Copy and set operations.
// Minimum and maximum operation functions and their pointers.
// Implementation in min_max_operations.c.
// Returns the largest absolute value in a signed 16-bit vector.
//
// Input:
// - vector : 16-bit input vector.
// - length : Number of samples in vector.
//
// Return value : Maximum absolute value in vector.
typedef int16_t (*MaxAbsValueW16)(const int16_t* vector, size_t length);
extern const MaxAbsValueW16 WebRtcSpl_MaxAbsValueW16;
int16_t WebRtcSpl_MaxAbsValueW16C(const int16_t* vector, size_t length);
#if defined(WEBRTC_HAS_NEON)
int16_t WebRtcSpl_MaxAbsValueW16Neon(const int16_t* vector, size_t length);
#endif
#if defined(MIPS32_LE)
int16_t WebRtcSpl_MaxAbsValueW16_mips(const int16_t* vector, size_t length);
#endif
// Returns the largest absolute value in a signed 32-bit vector.
//
// Input:
// - vector : 32-bit input vector.
// - length : Number of samples in vector.
//
// Return value : Maximum absolute value in vector.
typedef int32_t (*MaxAbsValueW32)(const int32_t* vector, size_t length);
extern const MaxAbsValueW32 WebRtcSpl_MaxAbsValueW32;
int32_t WebRtcSpl_MaxAbsValueW32C(const int32_t* vector, size_t length);
#if defined(WEBRTC_HAS_NEON)
int32_t WebRtcSpl_MaxAbsValueW32Neon(const int32_t* vector, size_t length);
#endif
#if defined(MIPS_DSP_R1_LE)
int32_t WebRtcSpl_MaxAbsValueW32_mips(const int32_t* vector, size_t length);
#endif
// Returns the maximum value of a 16-bit vector.
//
// Input:
// - vector : 16-bit input vector.
// - length : Number of samples in vector.
//
// Return value : Maximum sample value in `vector`.
typedef int16_t (*MaxValueW16)(const int16_t* vector, size_t length);
extern const MaxValueW16 WebRtcSpl_MaxValueW16;
int16_t WebRtcSpl_MaxValueW16C(const int16_t* vector, size_t length);
#if defined(WEBRTC_HAS_NEON)
int16_t WebRtcSpl_MaxValueW16Neon(const int16_t* vector, size_t length);
#endif
#if defined(MIPS32_LE)
int16_t WebRtcSpl_MaxValueW16_mips(const int16_t* vector, size_t length);
#endif
// Returns the maximum value of a 32-bit vector.
//
// Input:
// - vector : 32-bit input vector.
// - length : Number of samples in vector.
//
// Return value : Maximum sample value in `vector`.
typedef int32_t (*MaxValueW32)(const int32_t* vector, size_t length);
extern const MaxValueW32 WebRtcSpl_MaxValueW32;
int32_t WebRtcSpl_MaxValueW32C(const int32_t* vector, size_t length);
#if defined(WEBRTC_HAS_NEON)
int32_t WebRtcSpl_MaxValueW32Neon(const int32_t* vector, size_t length);
#endif
#if defined(MIPS32_LE)
int32_t WebRtcSpl_MaxValueW32_mips(const int32_t* vector, size_t length);
#endif
// Returns the minimum value of a 16-bit vector.
//
// Input:
// - vector : 16-bit input vector.
// - length : Number of samples in vector.
//
// Return value : Minimum sample value in `vector`.
typedef int16_t (*MinValueW16)(const int16_t* vector, size_t length);
extern const MinValueW16 WebRtcSpl_MinValueW16;
int16_t WebRtcSpl_MinValueW16C(const int16_t* vector, size_t length);
#if defined(WEBRTC_HAS_NEON)
int16_t WebRtcSpl_MinValueW16Neon(const int16_t* vector, size_t length);
#endif
#if defined(MIPS32_LE)
int16_t WebRtcSpl_MinValueW16_mips(const int16_t* vector, size_t length);
#endif
// Returns the minimum value of a 32-bit vector.
//
// Input:
// - vector : 32-bit input vector.
// - length : Number of samples in vector.
//
// Return value : Minimum sample value in `vector`.
typedef int32_t (*MinValueW32)(const int32_t* vector, size_t length);
extern const MinValueW32 WebRtcSpl_MinValueW32;
int32_t WebRtcSpl_MinValueW32C(const int32_t* vector, size_t length);
#if defined(WEBRTC_HAS_NEON)
int32_t WebRtcSpl_MinValueW32Neon(const int32_t* vector, size_t length);
#endif
#if defined(MIPS32_LE)
int32_t WebRtcSpl_MinValueW32_mips(const int32_t* vector, size_t length);
#endif
// Returns both the minimum and maximum values of a 16-bit vector.
//
// Input:
// - vector : 16-bit input vector.
// - length : Number of samples in vector.
// Ouput:
// - max_val : Maximum sample value in `vector`.
// - min_val : Minimum sample value in `vector`.
void WebRtcSpl_MinMaxW16(const int16_t* vector,
size_t length,
int16_t* min_val,
int16_t* max_val);
#if defined(WEBRTC_HAS_NEON)
void WebRtcSpl_MinMaxW16Neon(const int16_t* vector,
size_t length,
int16_t* min_val,
int16_t* max_val);
#endif
// Returns the vector index to the largest absolute value of a 16-bit vector.
//
// Input:
// - vector : 16-bit input vector.
// - length : Number of samples in vector.
//
// Return value : Index to the maximum absolute value in vector.
// If there are multiple equal maxima, return the index of the
// first. -32768 will always have precedence over 32767 (despite
// -32768 presenting an int16 absolute value of 32767).
size_t WebRtcSpl_MaxAbsIndexW16(const int16_t* vector, size_t length);
// Returns the element with the largest absolute value of a 16-bit vector. Note
// that this function can return a negative value.
//
// Input:
// - vector : 16-bit input vector.
// - length : Number of samples in vector.
//
// Return value : The element with the largest absolute value. Note that this
// may be a negative value.
int16_t WebRtcSpl_MaxAbsElementW16(const int16_t* vector, size_t length);
// Returns the vector index to the maximum sample value of a 16-bit vector.
//
// Input:
// - vector : 16-bit input vector.
// - length : Number of samples in vector.
//
// Return value : Index to the maximum value in vector (if multiple
// indexes have the maximum, return the first).
size_t WebRtcSpl_MaxIndexW16(const int16_t* vector, size_t length);
// Returns the vector index to the maximum sample value of a 32-bit vector.
//
// Input:
// - vector : 32-bit input vector.
// - length : Number of samples in vector.
//
// Return value : Index to the maximum value in vector (if multiple
// indexes have the maximum, return the first).
size_t WebRtcSpl_MaxIndexW32(const int32_t* vector, size_t length);
// Returns the vector index to the minimum sample value of a 16-bit vector.
//
// Input:
// - vector : 16-bit input vector.
// - length : Number of samples in vector.
//
// Return value : Index to the mimimum value in vector (if multiple
// indexes have the minimum, return the first).
size_t WebRtcSpl_MinIndexW16(const int16_t* vector, size_t length);
// Returns the vector index to the minimum sample value of a 32-bit vector.
//
// Input:
// - vector : 32-bit input vector.
// - length : Number of samples in vector.
//
// Return value : Index to the mimimum value in vector (if multiple
// indexes have the minimum, return the first).
size_t WebRtcSpl_MinIndexW32(const int32_t* vector, size_t length);
// End: Minimum and maximum operations.
// Vector scaling operations. Implementation in vector_scaling_operations.c.
// Description at bottom of file.
void WebRtcSpl_VectorBitShiftW16(int16_t* out_vector,
size_t vector_length,
const int16_t* in_vector,
int16_t right_shifts);
void WebRtcSpl_VectorBitShiftW32(int32_t* out_vector,
size_t vector_length,
const int32_t* in_vector,
int16_t right_shifts);
void WebRtcSpl_VectorBitShiftW32ToW16(int16_t* out_vector,
size_t vector_length,
const int32_t* in_vector,
int right_shifts);
void WebRtcSpl_ScaleVector(const int16_t* in_vector,
int16_t* out_vector,
int16_t gain,
size_t vector_length,
int16_t right_shifts);
void WebRtcSpl_ScaleVectorWithSat(const int16_t* in_vector,
int16_t* out_vector,
int16_t gain,
size_t vector_length,
int16_t right_shifts);
void WebRtcSpl_ScaleAndAddVectors(const int16_t* in_vector1,
int16_t gain1,
int right_shifts1,
const int16_t* in_vector2,
int16_t gain2,
int right_shifts2,
int16_t* out_vector,
size_t vector_length);
// The functions (with related pointer) perform the vector operation:
// out_vector[k] = ((scale1 * in_vector1[k]) + (scale2 * in_vector2[k])
// + round_value) >> right_shifts,
// where round_value = (1 << right_shifts) >> 1.
//
// Input:
// - in_vector1 : Input vector 1
// - in_vector1_scale : Gain to be used for vector 1
// - in_vector2 : Input vector 2
// - in_vector2_scale : Gain to be used for vector 2
// - right_shifts : Number of right bit shifts to be applied
// - length : Number of elements in the input vectors
//
// Output:
// - out_vector : Output vector
// Return value : 0 if OK, -1 if (in_vector1 == null
// || in_vector2 == null || out_vector == null
// || length <= 0 || right_shift < 0).
typedef int (*ScaleAndAddVectorsWithRound)(const int16_t* in_vector1,
int16_t in_vector1_scale,
const int16_t* in_vector2,
int16_t in_vector2_scale,
int right_shifts,
int16_t* out_vector,
size_t length);
extern const ScaleAndAddVectorsWithRound WebRtcSpl_ScaleAndAddVectorsWithRound;
int WebRtcSpl_ScaleAndAddVectorsWithRoundC(const int16_t* in_vector1,
int16_t in_vector1_scale,
const int16_t* in_vector2,
int16_t in_vector2_scale,
int right_shifts,
int16_t* out_vector,
size_t length);
#if defined(MIPS_DSP_R1_LE)
int WebRtcSpl_ScaleAndAddVectorsWithRound_mips(const int16_t* in_vector1,
int16_t in_vector1_scale,
const int16_t* in_vector2,
int16_t in_vector2_scale,
int right_shifts,
int16_t* out_vector,
size_t length);
#endif
// End: Vector scaling operations.
// iLBC specific functions. Implementations in ilbc_specific_functions.c.
// Description at bottom of file.
void WebRtcSpl_ReverseOrderMultArrayElements(int16_t* out_vector,
const int16_t* in_vector,
const int16_t* window,
size_t vector_length,
int16_t right_shifts);
void WebRtcSpl_ElementwiseVectorMult(int16_t* out_vector,
const int16_t* in_vector,
const int16_t* window,
size_t vector_length,
int16_t right_shifts);
void WebRtcSpl_AddVectorsAndShift(int16_t* out_vector,
const int16_t* in_vector1,
const int16_t* in_vector2,
size_t vector_length,
int16_t right_shifts);
void WebRtcSpl_AddAffineVectorToVector(int16_t* out_vector,
const int16_t* in_vector,
int16_t gain,
int32_t add_constant,
int16_t right_shifts,
size_t vector_length);
void WebRtcSpl_AffineTransformVector(int16_t* out_vector,
const int16_t* in_vector,
int16_t gain,
int32_t add_constant,
int16_t right_shifts,
size_t vector_length);
// End: iLBC specific functions.
// Signal processing operations.
// A 32-bit fix-point implementation of auto-correlation computation
//
// Input:
// - in_vector : Vector to calculate autocorrelation upon
// - in_vector_length : Length (in samples) of `vector`
// - order : The order up to which the autocorrelation should be
// calculated
//
// Output:
// - result : auto-correlation values (values should be seen
// relative to each other since the absolute values
// might have been down shifted to avoid overflow)
//
// - scale : The number of left shifts required to obtain the
// auto-correlation in Q0
//
// Return value : Number of samples in `result`, i.e. (order+1)
size_t WebRtcSpl_AutoCorrelation(const int16_t* in_vector,
size_t in_vector_length,
size_t order,
int32_t* result,
int* scale);
// A 32-bit fix-point implementation of the Levinson-Durbin algorithm that
// does NOT use the 64 bit class
//
// Input:
// - auto_corr : Vector with autocorrelation values of length >= `order`+1
// - order : The LPC filter order (support up to order 20)
//
// Output:
// - lpc_coef : lpc_coef[0..order] LPC coefficients in Q12
// - refl_coef : refl_coef[0...order-1]| Reflection coefficients in Q15
//
// Return value : 1 for stable 0 for unstable
int16_t WebRtcSpl_LevinsonDurbin(const int32_t* auto_corr,
int16_t* lpc_coef,
int16_t* refl_coef,
size_t order);
// Converts reflection coefficients `refl_coef` to LPC coefficients `lpc_coef`.
// This version is a 16 bit operation.
//
// NOTE: The 16 bit refl_coef -> lpc_coef conversion might result in a
// "slightly unstable" filter (i.e., a pole just outside the unit circle) in
// "rare" cases even if the reflection coefficients are stable.
//
// Input:
// - refl_coef : Reflection coefficients in Q15 that should be converted
// to LPC coefficients
// - use_order : Number of coefficients in `refl_coef`
//
// Output:
// - lpc_coef : LPC coefficients in Q12
void WebRtcSpl_ReflCoefToLpc(const int16_t* refl_coef,
int use_order,
int16_t* lpc_coef);
// Converts LPC coefficients `lpc_coef` to reflection coefficients `refl_coef`.
// This version is a 16 bit operation.
// The conversion is implemented by the step-down algorithm.
//
// Input:
// - lpc_coef : LPC coefficients in Q12, that should be converted to
// reflection coefficients
// - use_order : Number of coefficients in `lpc_coef`
//
// Output:
// - refl_coef : Reflection coefficients in Q15.
void WebRtcSpl_LpcToReflCoef(int16_t* lpc_coef,
int use_order,
int16_t* refl_coef);
// Calculates reflection coefficients (16 bit) from auto-correlation values
//
// Input:
// - auto_corr : Auto-correlation values
// - use_order : Number of coefficients wanted be calculated
//
// Output:
// - refl_coef : Reflection coefficients in Q15.
void WebRtcSpl_AutoCorrToReflCoef(const int32_t* auto_corr,
int use_order,
int16_t* refl_coef);
// The functions (with related pointer) calculate the cross-correlation between
// two sequences `seq1` and `seq2`.
// `seq1` is fixed and `seq2` slides as the pointer is increased with the
// amount `step_seq2`. Note the arguments should obey the relationship:
// `dim_seq` - 1 + `step_seq2` * (`dim_cross_correlation` - 1) <
// buffer size of `seq2`
//
// Input:
// - seq1 : First sequence (fixed throughout the correlation)
// - seq2 : Second sequence (slides `step_vector2` for each
// new correlation)
// - dim_seq : Number of samples to use in the cross-correlation
// - dim_cross_correlation : Number of cross-correlations to calculate (the
// start position for `vector2` is updated for each
// new one)
// - right_shifts : Number of right bit shifts to use. This will
// become the output Q-domain.
// - step_seq2 : How many (positive or negative) steps the
// `vector2` pointer should be updated for each new
// cross-correlation value.
//
// Output:
// - cross_correlation : The cross-correlation in Q(-right_shifts)
typedef void (*CrossCorrelation)(int32_t* cross_correlation,
const int16_t* seq1,
const int16_t* seq2,
size_t dim_seq,
size_t dim_cross_correlation,
int right_shifts,
int step_seq2);
extern const CrossCorrelation WebRtcSpl_CrossCorrelation;
void WebRtcSpl_CrossCorrelationC(int32_t* cross_correlation,
const int16_t* seq1,
const int16_t* seq2,
size_t dim_seq,
size_t dim_cross_correlation,
int right_shifts,
int step_seq2);
#if defined(WEBRTC_HAS_NEON)
void WebRtcSpl_CrossCorrelationNeon(int32_t* cross_correlation,
const int16_t* seq1,
const int16_t* seq2,
size_t dim_seq,
size_t dim_cross_correlation,
int right_shifts,
int step_seq2);
#endif
#if defined(MIPS32_LE)
void WebRtcSpl_CrossCorrelation_mips(int32_t* cross_correlation,
const int16_t* seq1,
const int16_t* seq2,
size_t dim_seq,
size_t dim_cross_correlation,
int right_shifts,
int step_seq2);
#endif
// Creates (the first half of) a Hanning window. Size must be at least 1 and
// at most 512.
//
// Input:
// - size : Length of the requested Hanning window (1 to 512)
//
// Output:
// - window : Hanning vector in Q14.
void WebRtcSpl_GetHanningWindow(int16_t* window, size_t size);
// Calculates y[k] = sqrt(1 - x[k]^2) for each element of the input vector
// `in_vector`. Input and output values are in Q15.
//
// Inputs:
// - in_vector : Values to calculate sqrt(1 - x^2) of
// - vector_length : Length of vector `in_vector`
//
// Output:
// - out_vector : Output values in Q15
void WebRtcSpl_SqrtOfOneMinusXSquared(int16_t* in_vector,
size_t vector_length,
int16_t* out_vector);
// End: Signal processing operations.
// Randomization functions. Implementations collected in
// randomization_functions.c and descriptions at bottom of this file.
int16_t WebRtcSpl_RandU(uint32_t* seed);
int16_t WebRtcSpl_RandN(uint32_t* seed);
int16_t WebRtcSpl_RandUArray(int16_t* vector,
int16_t vector_length,
uint32_t* seed);
// End: Randomization functions.
// Math functions
int32_t WebRtcSpl_Sqrt(int32_t value);
// Divisions. Implementations collected in division_operations.c and
// descriptions at bottom of this file.
uint32_t WebRtcSpl_DivU32U16(uint32_t num, uint16_t den);
int32_t WebRtcSpl_DivW32W16(int32_t num, int16_t den);
int16_t WebRtcSpl_DivW32W16ResW16(int32_t num, int16_t den);
int32_t WebRtcSpl_DivResultInQ31(int32_t num, int32_t den);
int32_t WebRtcSpl_DivW32HiLow(int32_t num, int16_t den_hi, int16_t den_low);
// End: Divisions.
int32_t WebRtcSpl_Energy(int16_t* vector,
size_t vector_length,
int* scale_factor);
// Filter operations.
size_t WebRtcSpl_FilterAR(const int16_t* ar_coef,
size_t ar_coef_length,
const int16_t* in_vector,
size_t in_vector_length,
int16_t* filter_state,
size_t filter_state_length,
int16_t* filter_state_low,
int16_t* out_vector,
int16_t* out_vector_low);
// WebRtcSpl_FilterMAFastQ12(...)
//
// Performs a MA filtering on a vector in Q12
//
// Input:
// - in_vector : Input samples (state in positions
// in_vector[-order] .. in_vector[-1])
// - ma_coef : Filter coefficients (in Q12)
// - ma_coef_length : Number of B coefficients (order+1)
// - vector_length : Number of samples to be filtered
//
// Output:
// - out_vector : Filtered samples
//
void WebRtcSpl_FilterMAFastQ12(const int16_t* in_vector,
int16_t* out_vector,
const int16_t* ma_coef,
size_t ma_coef_length,
size_t vector_length);
// Performs a AR filtering on a vector in Q12
// Input:
// - data_in : Input samples
// - data_out : State information in positions
// data_out[-order] .. data_out[-1]
// - coefficients : Filter coefficients (in Q12)
// - coefficients_length: Number of coefficients (order+1)
// - data_length : Number of samples to be filtered
// Output:
// - data_out : Filtered samples
void WebRtcSpl_FilterARFastQ12(const int16_t* data_in,
int16_t* data_out,
const int16_t* __restrict coefficients,
size_t coefficients_length,
size_t data_length);
// The functions (with related pointer) perform a MA down sampling filter
// on a vector.
// Input:
// - data_in : Input samples (state in positions
// data_in[-order] .. data_in[-1])
// - data_in_length : Number of samples in `data_in` to be filtered.
// This must be at least
// `delay` + `factor`*(`out_vector_length`-1) + 1)
// - data_out_length : Number of down sampled samples desired
// - coefficients : Filter coefficients (in Q12)
// - coefficients_length: Number of coefficients (order+1)
// - factor : Decimation factor
// - delay : Delay of filter (compensated for in out_vector)
// Output:
// - data_out : Filtered samples
// Return value : 0 if OK, -1 if `in_vector` is too short
typedef int (*DownsampleFast)(const int16_t* data_in,
size_t data_in_length,
int16_t* data_out,
size_t data_out_length,
const int16_t* __restrict coefficients,
size_t coefficients_length,
int factor,
size_t delay);
extern const DownsampleFast WebRtcSpl_DownsampleFast;
int WebRtcSpl_DownsampleFastC(const int16_t* data_in,
size_t data_in_length,
int16_t* data_out,
size_t data_out_length,
const int16_t* __restrict coefficients,
size_t coefficients_length,
int factor,
size_t delay);
#if defined(WEBRTC_HAS_NEON)
int WebRtcSpl_DownsampleFastNeon(const int16_t* data_in,
size_t data_in_length,
int16_t* data_out,
size_t data_out_length,
const int16_t* __restrict coefficients,
size_t coefficients_length,
int factor,
size_t delay);
#endif
#if defined(MIPS32_LE)
int WebRtcSpl_DownsampleFast_mips(const int16_t* data_in,
size_t data_in_length,
int16_t* data_out,
size_t data_out_length,
const int16_t* __restrict coefficients,
size_t coefficients_length,
int factor,
size_t delay);
#endif
// End: Filter operations.
// FFT operations
int WebRtcSpl_ComplexFFT(int16_t vector[], int stages, int mode);
int WebRtcSpl_ComplexIFFT(int16_t vector[], int stages, int mode);
// Treat a 16-bit complex data buffer `complex_data` as an array of 32-bit
// values, and swap elements whose indexes are bit-reverses of each other.
//
// Input:
// - complex_data : Complex data buffer containing 2^`stages` real
// elements interleaved with 2^`stages` imaginary
// elements: [Re Im Re Im Re Im....]
// - stages : Number of FFT stages. Must be at least 3 and at most
// 10, since the table WebRtcSpl_kSinTable1024[] is 1024
// elements long.
//
// Output:
// - complex_data : The complex data buffer.
void WebRtcSpl_ComplexBitReverse(int16_t* __restrict complex_data, int stages);
// End: FFT operations
/************************************************************
*
* RESAMPLING FUNCTIONS AND THEIR STRUCTS ARE DEFINED BELOW
*
************************************************************/
/*******************************************************************
* resample.c
*
* Includes the following resampling combinations
* 22 kHz -> 16 kHz
* 16 kHz -> 22 kHz
* 22 kHz -> 8 kHz
* 8 kHz -> 22 kHz
*
******************************************************************/
// state structure for 22 -> 16 resampler
typedef struct {
int32_t S_22_44[8];
int32_t S_44_32[8];
int32_t S_32_16[8];
} WebRtcSpl_State22khzTo16khz;
void WebRtcSpl_Resample22khzTo16khz(const int16_t* in,
int16_t* out,
WebRtcSpl_State22khzTo16khz* state,
int32_t* tmpmem);
void WebRtcSpl_ResetResample22khzTo16khz(WebRtcSpl_State22khzTo16khz* state);
// state structure for 16 -> 22 resampler
typedef struct {
int32_t S_16_32[8];
int32_t S_32_22[8];
} WebRtcSpl_State16khzTo22khz;
void WebRtcSpl_Resample16khzTo22khz(const int16_t* in,
int16_t* out,
WebRtcSpl_State16khzTo22khz* state,
int32_t* tmpmem);
void WebRtcSpl_ResetResample16khzTo22khz(WebRtcSpl_State16khzTo22khz* state);
// state structure for 22 -> 8 resampler
typedef struct {
int32_t S_22_22[16];
int32_t S_22_16[8];
int32_t S_16_8[8];
} WebRtcSpl_State22khzTo8khz;
void WebRtcSpl_Resample22khzTo8khz(const int16_t* in,
int16_t* out,
WebRtcSpl_State22khzTo8khz* state,
int32_t* tmpmem);
void WebRtcSpl_ResetResample22khzTo8khz(WebRtcSpl_State22khzTo8khz* state);
// state structure for 8 -> 22 resampler
typedef struct {
int32_t S_8_16[8];
int32_t S_16_11[8];
int32_t S_11_22[8];
} WebRtcSpl_State8khzTo22khz;
void WebRtcSpl_Resample8khzTo22khz(const int16_t* in,
int16_t* out,
WebRtcSpl_State8khzTo22khz* state,
int32_t* tmpmem);
void WebRtcSpl_ResetResample8khzTo22khz(WebRtcSpl_State8khzTo22khz* state);
/*******************************************************************
* resample_fractional.c
* Functions for internal use in the other resample functions
*
* Includes the following resampling combinations
* 48 kHz -> 32 kHz
* 32 kHz -> 24 kHz
* 44 kHz -> 32 kHz
*
******************************************************************/
void WebRtcSpl_Resample48khzTo32khz(const int32_t* In, int32_t* Out, size_t K);
void WebRtcSpl_Resample32khzTo24khz(const int32_t* In, int32_t* Out, size_t K);
void WebRtcSpl_Resample44khzTo32khz(const int32_t* In, int32_t* Out, size_t K);
/*******************************************************************
* resample_48khz.c
*
* Includes the following resampling combinations
* 48 kHz -> 16 kHz
* 16 kHz -> 48 kHz
* 48 kHz -> 8 kHz
* 8 kHz -> 48 kHz
*
******************************************************************/
typedef struct {
int32_t S_48_48[16];
int32_t S_48_32[8];
int32_t S_32_16[8];
} WebRtcSpl_State48khzTo16khz;
void WebRtcSpl_Resample48khzTo16khz(const int16_t* in,
int16_t* out,
WebRtcSpl_State48khzTo16khz* state,
int32_t* tmpmem);
void WebRtcSpl_ResetResample48khzTo16khz(WebRtcSpl_State48khzTo16khz* state);
typedef struct {
int32_t S_16_32[8];
int32_t S_32_24[8];
int32_t S_24_48[8];
} WebRtcSpl_State16khzTo48khz;
void WebRtcSpl_Resample16khzTo48khz(const int16_t* in,
int16_t* out,
WebRtcSpl_State16khzTo48khz* state,
int32_t* tmpmem);
void WebRtcSpl_ResetResample16khzTo48khz(WebRtcSpl_State16khzTo48khz* state);
typedef struct {
int32_t S_48_24[8];
int32_t S_24_24[16];
int32_t S_24_16[8];
int32_t S_16_8[8];
} WebRtcSpl_State48khzTo8khz;
void WebRtcSpl_Resample48khzTo8khz(const int16_t* in,
int16_t* out,
WebRtcSpl_State48khzTo8khz* state,
int32_t* tmpmem);
void WebRtcSpl_ResetResample48khzTo8khz(WebRtcSpl_State48khzTo8khz* state);
typedef struct {
int32_t S_8_16[8];
int32_t S_16_12[8];
int32_t S_12_24[8];
int32_t S_24_48[8];
} WebRtcSpl_State8khzTo48khz;
void WebRtcSpl_Resample8khzTo48khz(const int16_t* in,
int16_t* out,
WebRtcSpl_State8khzTo48khz* state,
int32_t* tmpmem);
void WebRtcSpl_ResetResample8khzTo48khz(WebRtcSpl_State8khzTo48khz* state);
/*******************************************************************
* resample_by_2.c
*
* Includes down and up sampling by a factor of two.
*
******************************************************************/
void WebRtcSpl_DownsampleBy2(const int16_t* in,
size_t len,
int16_t* out,
int32_t* filtState);
void WebRtcSpl_UpsampleBy2(const int16_t* in,
size_t len,
int16_t* out,
int32_t* filtState);
/************************************************************
* END OF RESAMPLING FUNCTIONS
************************************************************/
void WebRtcSpl_AnalysisQMF(const int16_t* in_data,
size_t in_data_length,
int16_t* low_band,
int16_t* high_band,
int32_t* filter_state1,
int32_t* filter_state2);
void WebRtcSpl_SynthesisQMF(const int16_t* low_band,
const int16_t* high_band,
size_t band_length,
int16_t* out_data,
int32_t* filter_state1,
int32_t* filter_state2);
#ifdef __cplusplus
}
#endif // __cplusplus
#endif // COMMON_AUDIO_SIGNAL_PROCESSING_INCLUDE_SIGNAL_PROCESSING_LIBRARY_H_
//
// WebRtcSpl_AddSatW16(...)
// WebRtcSpl_AddSatW32(...)
//
// Returns the result of a saturated 16-bit, respectively 32-bit, addition of
// the numbers specified by the `var1` and `var2` parameters.
//
// Input:
// - var1 : Input variable 1
// - var2 : Input variable 2
//
// Return value : Added and saturated value
//
//
// WebRtcSpl_SubSatW16(...)
// WebRtcSpl_SubSatW32(...)
//
// Returns the result of a saturated 16-bit, respectively 32-bit, subtraction
// of the numbers specified by the `var1` and `var2` parameters.
//
// Input:
// - var1 : Input variable 1
// - var2 : Input variable 2
//
// Returned value : Subtracted and saturated value
//
//
// WebRtcSpl_GetSizeInBits(...)
//
// Returns the # of bits that are needed at the most to represent the number
// specified by the `value` parameter.
//
// Input:
// - value : Input value
//
// Return value : Number of bits needed to represent `value`
//
//
// WebRtcSpl_NormW32(...)
//
// Norm returns the # of left shifts required to 32-bit normalize the 32-bit
// signed number specified by the `value` parameter.
//
// Input:
// - value : Input value
//
// Return value : Number of bit shifts needed to 32-bit normalize `value`
//
//
// WebRtcSpl_NormW16(...)
//
// Norm returns the # of left shifts required to 16-bit normalize the 16-bit
// signed number specified by the `value` parameter.
//
// Input:
// - value : Input value
//
// Return value : Number of bit shifts needed to 32-bit normalize `value`
//
//
// WebRtcSpl_NormU32(...)
//
// Norm returns the # of left shifts required to 32-bit normalize the unsigned
// 32-bit number specified by the `value` parameter.
//
// Input:
// - value : Input value
//
// Return value : Number of bit shifts needed to 32-bit normalize `value`
//
//
// WebRtcSpl_GetScalingSquare(...)
//
// Returns the # of bits required to scale the samples specified in the
// `in_vector` parameter so that, if the squares of the samples are added the
// # of times specified by the `times` parameter, the 32-bit addition will not
// overflow (result in int32_t).
//
// Input:
// - in_vector : Input vector to check scaling on
// - in_vector_length : Samples in `in_vector`
// - times : Number of additions to be performed
//
// Return value : Number of right bit shifts needed to avoid
// overflow in the addition calculation
//
//
// WebRtcSpl_MemSetW16(...)
//
// Sets all the values in the int16_t vector `vector` of length
// `vector_length` to the specified value `set_value`
//
// Input:
// - vector : Pointer to the int16_t vector
// - set_value : Value specified
// - vector_length : Length of vector
//
//
// WebRtcSpl_MemSetW32(...)
//
// Sets all the values in the int32_t vector `vector` of length
// `vector_length` to the specified value `set_value`
//
// Input:
// - vector : Pointer to the int16_t vector
// - set_value : Value specified
// - vector_length : Length of vector
//
//
// WebRtcSpl_MemCpyReversedOrder(...)
//
// Copies all the values from the source int16_t vector `in_vector` to a
// destination int16_t vector `out_vector`. It is done in reversed order,
// meaning that the first sample of `in_vector` is copied to the last sample of
// the `out_vector`. The procedure continues until the last sample of
// `in_vector` has been copied to the first sample of `out_vector`. This
// creates a reversed vector. Used in e.g. prediction in iLBC.
//
// Input:
// - in_vector : Pointer to the first sample in a int16_t vector
// of length `length`
// - vector_length : Number of elements to copy
//
// Output:
// - out_vector : Pointer to the last sample in a int16_t vector
// of length `length`
//
//
// WebRtcSpl_CopyFromEndW16(...)
//
// Copies the rightmost `samples` of `in_vector` (of length `in_vector_length`)
// to the vector `out_vector`.
//
// Input:
// - in_vector : Input vector
// - in_vector_length : Number of samples in `in_vector`
// - samples : Number of samples to extract (from right side)
// from `in_vector`
//
// Output:
// - out_vector : Vector with the requested samples
//
//
// WebRtcSpl_ZerosArrayW16(...)
// WebRtcSpl_ZerosArrayW32(...)
//
// Inserts the value "zero" in all positions of a w16 and a w32 vector
// respectively.
//
// Input:
// - vector_length : Number of samples in vector
//
// Output:
// - vector : Vector containing all zeros
//
//
// WebRtcSpl_VectorBitShiftW16(...)
// WebRtcSpl_VectorBitShiftW32(...)
//
// Bit shifts all the values in a vector up or downwards. Different calls for
// int16_t and int32_t vectors respectively.
//
// Input:
// - vector_length : Length of vector
// - in_vector : Pointer to the vector that should be bit shifted
// - right_shifts : Number of right bit shifts (negative value gives left
// shifts)
//
// Output:
// - out_vector : Pointer to the result vector (can be the same as
// `in_vector`)
//
//
// WebRtcSpl_VectorBitShiftW32ToW16(...)
//
// Bit shifts all the values in a int32_t vector up or downwards and
// stores the result as an int16_t vector. The function will saturate the
// signal if needed, before storing in the output vector.
//
// Input:
// - vector_length : Length of vector
// - in_vector : Pointer to the vector that should be bit shifted
// - right_shifts : Number of right bit shifts (negative value gives left
// shifts)
//
// Output:
// - out_vector : Pointer to the result vector (can be the same as
// `in_vector`)
//
//
// WebRtcSpl_ScaleVector(...)
//
// Performs the vector operation:
// out_vector[k] = (gain*in_vector[k])>>right_shifts
//
// Input:
// - in_vector : Input vector
// - gain : Scaling gain
// - vector_length : Elements in the `in_vector`
// - right_shifts : Number of right bit shifts applied
//
// Output:
// - out_vector : Output vector (can be the same as `in_vector`)
//
//
// WebRtcSpl_ScaleVectorWithSat(...)
//
// Performs the vector operation:
// out_vector[k] = SATURATE( (gain*in_vector[k])>>right_shifts )
//
// Input:
// - in_vector : Input vector
// - gain : Scaling gain
// - vector_length : Elements in the `in_vector`
// - right_shifts : Number of right bit shifts applied
//
// Output:
// - out_vector : Output vector (can be the same as `in_vector`)
//
//
// WebRtcSpl_ScaleAndAddVectors(...)
//
// Performs the vector operation:
// out_vector[k] = (gain1*in_vector1[k])>>right_shifts1
// + (gain2*in_vector2[k])>>right_shifts2
//
// Input:
// - in_vector1 : Input vector 1
// - gain1 : Gain to be used for vector 1
// - right_shifts1 : Right bit shift to be used for vector 1
// - in_vector2 : Input vector 2
// - gain2 : Gain to be used for vector 2
// - right_shifts2 : Right bit shift to be used for vector 2
// - vector_length : Elements in the input vectors
//
// Output:
// - out_vector : Output vector
//
//
// WebRtcSpl_ReverseOrderMultArrayElements(...)
//
// Performs the vector operation:
// out_vector[n] = (in_vector[n]*window[-n])>>right_shifts
//
// Input:
// - in_vector : Input vector
// - window : Window vector (should be reversed). The pointer
// should be set to the last value in the vector
// - right_shifts : Number of right bit shift to be applied after the
// multiplication
// - vector_length : Number of elements in `in_vector`
//
// Output:
// - out_vector : Output vector (can be same as `in_vector`)
//
//
// WebRtcSpl_ElementwiseVectorMult(...)
//
// Performs the vector operation:
// out_vector[n] = (in_vector[n]*window[n])>>right_shifts
//
// Input:
// - in_vector : Input vector
// - window : Window vector.
// - right_shifts : Number of right bit shift to be applied after the
// multiplication
// - vector_length : Number of elements in `in_vector`
//
// Output:
// - out_vector : Output vector (can be same as `in_vector`)
//
//
// WebRtcSpl_AddVectorsAndShift(...)
//
// Performs the vector operation:
// out_vector[k] = (in_vector1[k] + in_vector2[k])>>right_shifts
//
// Input:
// - in_vector1 : Input vector 1
// - in_vector2 : Input vector 2
// - right_shifts : Number of right bit shift to be applied after the
// multiplication
// - vector_length : Number of elements in `in_vector1` and `in_vector2`
//
// Output:
// - out_vector : Output vector (can be same as `in_vector1`)
//
//
// WebRtcSpl_AddAffineVectorToVector(...)
//
// Adds an affine transformed vector to another vector `out_vector`, i.e,
// performs
// out_vector[k] += (in_vector[k]*gain+add_constant)>>right_shifts
//
// Input:
// - in_vector : Input vector
// - gain : Gain value, used to multiply the in vector with
// - add_constant : Constant value to add (usually 1<<(right_shifts-1),
// but others can be used as well
// - right_shifts : Number of right bit shifts (0-16)
// - vector_length : Number of samples in `in_vector` and `out_vector`
//
// Output:
// - out_vector : Vector with the output
//
//
// WebRtcSpl_AffineTransformVector(...)
//
// Affine transforms a vector, i.e, performs
// out_vector[k] = (in_vector[k]*gain+add_constant)>>right_shifts
//
// Input:
// - in_vector : Input vector
// - gain : Gain value, used to multiply the in vector with
// - add_constant : Constant value to add (usually 1<<(right_shifts-1),
// but others can be used as well
// - right_shifts : Number of right bit shifts (0-16)
// - vector_length : Number of samples in `in_vector` and `out_vector`
//
// Output:
// - out_vector : Vector with the output
//
//
// WebRtcSpl_IncreaseSeed(...)
//
// Increases the seed (and returns the new value)
//
// Input:
// - seed : Seed for random calculation
//
// Output:
// - seed : Updated seed value
//
// Return value : The new seed value
//
//
// WebRtcSpl_RandU(...)
//
// Produces a uniformly distributed value in the int16_t range
//
// Input:
// - seed : Seed for random calculation
//
// Output:
// - seed : Updated seed value
//
// Return value : Uniformly distributed value in the range
// [Word16_MIN...Word16_MAX]
//
//
// WebRtcSpl_RandN(...)
//
// Produces a normal distributed value in the int16_t range
//
// Input:
// - seed : Seed for random calculation
//
// Output:
// - seed : Updated seed value
//
// Return value : N(0,1) value in the Q13 domain
//
//
// WebRtcSpl_RandUArray(...)
//
// Produces a uniformly distributed vector with elements in the int16_t
// range
//
// Input:
// - vector_length : Samples wanted in the vector
// - seed : Seed for random calculation
//
// Output:
// - vector : Vector with the uniform values
// - seed : Updated seed value
//
// Return value : Number of samples in vector, i.e., `vector_length`
//
//
// WebRtcSpl_Sqrt(...)
//
// Returns the square root of the input value `value`. The precision of this
// function is integer precision, i.e., sqrt(8) gives 2 as answer.
// If `value` is a negative number then 0 is returned.
//
// Algorithm:
//
// A sixth order Taylor Series expansion is used here to compute the square
// root of a number y^0.5 = (1+x)^0.5
// where
// x = y-1
// = 1+(x/2)-0.5*((x/2)^2+0.5*((x/2)^3-0.625*((x/2)^4+0.875*((x/2)^5)
// 0.5 <= x < 1
//
// Input:
// - value : Value to calculate sqrt of
//
// Return value : Result of the sqrt calculation
//
//
// WebRtcSpl_DivU32U16(...)
//
// Divides a uint32_t `num` by a uint16_t `den`.
//
// If `den`==0, (uint32_t)0xFFFFFFFF is returned.
//
// Input:
// - num : Numerator
// - den : Denominator
//
// Return value : Result of the division (as a uint32_t), i.e., the
// integer part of num/den.
//
//
// WebRtcSpl_DivW32W16(...)
//
// Divides a int32_t `num` by a int16_t `den`.
//
// If `den`==0, (int32_t)0x7FFFFFFF is returned.
//
// Input:
// - num : Numerator
// - den : Denominator
//
// Return value : Result of the division (as a int32_t), i.e., the
// integer part of num/den.
//
//
// WebRtcSpl_DivW32W16ResW16(...)
//
// Divides a int32_t `num` by a int16_t `den`, assuming that the
// result is less than 32768, otherwise an unpredictable result will occur.
//
// If `den`==0, (int16_t)0x7FFF is returned.
//
// Input:
// - num : Numerator
// - den : Denominator
//
// Return value : Result of the division (as a int16_t), i.e., the
// integer part of num/den.
//
//
// WebRtcSpl_DivResultInQ31(...)
//
// Divides a int32_t `num` by a int16_t `den`, assuming that the
// absolute value of the denominator is larger than the numerator, otherwise
// an unpredictable result will occur.
//
// Input:
// - num : Numerator
// - den : Denominator
//
// Return value : Result of the division in Q31.
//
//
// WebRtcSpl_DivW32HiLow(...)
//
// Divides a int32_t `num` by a denominator in hi, low format. The
// absolute value of the denominator has to be larger (or equal to) the
// numerator.
//
// Input:
// - num : Numerator
// - den_hi : High part of denominator
// - den_low : Low part of denominator
//
// Return value : Divided value in Q31
//
//
// WebRtcSpl_Energy(...)
//
// Calculates the energy of a vector
//
// Input:
// - vector : Vector which the energy should be calculated on
// - vector_length : Number of samples in vector
//
// Output:
// - scale_factor : Number of left bit shifts needed to get the physical
// energy value, i.e, to get the Q0 value
//
// Return value : Energy value in Q(-`scale_factor`)
//
//
// WebRtcSpl_FilterAR(...)
//
// Performs a 32-bit AR filtering on a vector in Q12
//
// Input:
// - ar_coef : AR-coefficient vector (values in Q12),
// ar_coef[0] must be 4096.
// - ar_coef_length : Number of coefficients in `ar_coef`.
// - in_vector : Vector to be filtered.
// - in_vector_length : Number of samples in `in_vector`.
// - filter_state : Current state (higher part) of the filter.
// - filter_state_length : Length (in samples) of `filter_state`.
// - filter_state_low : Current state (lower part) of the filter.
//
// Output:
// - filter_state : Updated state (upper part) vector.
// - filter_state_low : Updated state (lower part) vector.
// - out_vector : Vector containing the upper part of the
// filtered values.
// - out_vector_low : Vector containing the lower part of the
// filtered values.
//
// Return value : Number of samples in the `out_vector`.
//
//
// WebRtcSpl_ComplexIFFT(...)
//
// Complex Inverse FFT
//
// Computes an inverse complex 2^`stages`-point FFT on the input vector, which
// is in bit-reversed order. The original content of the vector is destroyed in
// the process, since the input is overwritten by the output, normal-ordered,
// FFT vector. With X as the input complex vector, y as the output complex
// vector and with M = 2^`stages`, the following is computed:
//
// M-1
// y(k) = sum[X(i)*[cos(2*pi*i*k/M) + j*sin(2*pi*i*k/M)]]
// i=0
//
// The implementations are optimized for speed, not for code size. It uses the
// decimation-in-time algorithm with radix-2 butterfly technique.
//
// Input:
// - vector : In pointer to complex vector containing 2^`stages`
// real elements interleaved with 2^`stages` imaginary
// elements.
// [ReImReImReIm....]
// The elements are in Q(-scale) domain, see more on Return
// Value below.
//
// - stages : Number of FFT stages. Must be at least 3 and at most 10,
// since the table WebRtcSpl_kSinTable1024[] is 1024
// elements long.
//
// - mode : This parameter gives the user to choose how the FFT
// should work.
// mode==0: Low-complexity and Low-accuracy mode
// mode==1: High-complexity and High-accuracy mode
//
// Output:
// - vector : Out pointer to the FFT vector (the same as input).
//
// Return Value : The scale value that tells the number of left bit shifts
// that the elements in the `vector` should be shifted with
// in order to get Q0 values, i.e. the physically correct
// values. The scale parameter is always 0 or positive,
// except if N>1024 (`stages`>10), which returns a scale
// value of -1, indicating error.
//
//
// WebRtcSpl_ComplexFFT(...)
//
// Complex FFT
//
// Computes a complex 2^`stages`-point FFT on the input vector, which is in
// bit-reversed order. The original content of the vector is destroyed in
// the process, since the input is overwritten by the output, normal-ordered,
// FFT vector. With x as the input complex vector, Y as the output complex
// vector and with M = 2^`stages`, the following is computed:
//
// M-1
// Y(k) = 1/M * sum[x(i)*[cos(2*pi*i*k/M) + j*sin(2*pi*i*k/M)]]
// i=0
//
// The implementations are optimized for speed, not for code size. It uses the
// decimation-in-time algorithm with radix-2 butterfly technique.
//
// This routine prevents overflow by scaling by 2 before each FFT stage. This is
// a fixed scaling, for proper normalization - there will be log2(n) passes, so
// this results in an overall factor of 1/n, distributed to maximize arithmetic
// accuracy.
//
// Input:
// - vector : In pointer to complex vector containing 2^`stages` real
// elements interleaved with 2^`stages` imaginary elements.
// [ReImReImReIm....]
// The output is in the Q0 domain.
//
// - stages : Number of FFT stages. Must be at least 3 and at most 10,
// since the table WebRtcSpl_kSinTable1024[] is 1024
// elements long.
//
// - mode : This parameter gives the user to choose how the FFT
// should work.
// mode==0: Low-complexity and Low-accuracy mode
// mode==1: High-complexity and High-accuracy mode
//
// Output:
// - vector : The output FFT vector is in the Q0 domain.
//
// Return value : The scale parameter is always 0, except if N>1024,
// which returns a scale value of -1, indicating error.
//
//
// WebRtcSpl_AnalysisQMF(...)
//
// Splits a 0-2*F Hz signal into two sub bands: 0-F Hz and F-2*F Hz. The
// current version has F = 8000, therefore, a super-wideband audio signal is
// split to lower-band 0-8 kHz and upper-band 8-16 kHz.
//
// Input:
// - in_data : Wide band speech signal, 320 samples (10 ms)
//
// Input & Output:
// - filter_state1 : Filter state for first All-pass filter
// - filter_state2 : Filter state for second All-pass filter
//
// Output:
// - low_band : Lower-band signal 0-8 kHz band, 160 samples (10 ms)
// - high_band : Upper-band signal 8-16 kHz band (flipped in frequency
// domain), 160 samples (10 ms)
//
//
// WebRtcSpl_SynthesisQMF(...)
//
// Combines the two sub bands (0-F and F-2*F Hz) into a signal of 0-2*F
// Hz, (current version has F = 8000 Hz). So the filter combines lower-band
// (0-8 kHz) and upper-band (8-16 kHz) channels to obtain super-wideband 0-16
// kHz audio.
//
// Input:
// - low_band : The signal with the 0-8 kHz band, 160 samples (10 ms)
// - high_band : The signal with the 8-16 kHz band, 160 samples (10 ms)
//
// Input & Output:
// - filter_state1 : Filter state for first All-pass filter
// - filter_state2 : Filter state for second All-pass filter
//
// Output:
// - out_data : Super-wideband speech signal, 0-16 kHz
//
// int16_t WebRtcSpl_SatW32ToW16(...)
//
// This function saturates a 32-bit word into a 16-bit word.
//
// Input:
// - value32 : The value of a 32-bit word.
//
// Output:
// - out16 : the saturated 16-bit word.
//
// int32_t WebRtc_MulAccumW16(...)
//
// This function multiply a 16-bit word by a 16-bit word, and accumulate this
// value to a 32-bit integer.
//
// Input:
// - a : The value of the first 16-bit word.
// - b : The value of the second 16-bit word.
// - c : The value of an 32-bit integer.
//
// Return Value: The value of a * b + c.
//
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