blob: 31d4e086bf7fd757d8365effa484e061dc09bb9c [file] [log] [blame]
/*
* 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.
*/
#include "webrtc/rtc_base/checks.h"
#include "webrtc/modules/audio_coding/codecs/isac/fix/source/codec.h"
// Autocorrelation function in fixed point.
// NOTE! Different from SPLIB-version in how it scales the signal.
int WebRtcIsacfix_AutocorrC(int32_t* __restrict r,
const int16_t* __restrict x,
int16_t N,
int16_t order,
int16_t* __restrict scale) {
int i = 0;
int j = 0;
int16_t scaling = 0;
int32_t sum = 0;
uint32_t temp = 0;
int64_t prod = 0;
// The ARM assembly code assumptoins.
RTC_DCHECK_EQ(0, N % 4);
RTC_DCHECK_GE(N, 8);
// Calculate r[0].
for (i = 0; i < N; i++) {
prod += x[i] * x[i];
}
// Calculate scaling (the value of shifting).
temp = (uint32_t)(prod >> 31);
if(temp == 0) {
scaling = 0;
} else {
scaling = 32 - WebRtcSpl_NormU32(temp);
}
r[0] = (int32_t)(prod >> scaling);
// Perform the actual correlation calculation.
for (i = 1; i < order + 1; i++) {
prod = 0;
for (j = 0; j < N - i; j++) {
prod += x[j] * x[i + j];
}
sum = (int32_t)(prod >> scaling);
r[i] = sum;
}
*scale = scaling;
return(order + 1);
}
static const int32_t kApUpperQ15[ALLPASSSECTIONS] = { 1137, 12537 };
static const int32_t kApLowerQ15[ALLPASSSECTIONS] = { 5059, 24379 };
static void AllpassFilterForDec32(int16_t *InOut16, //Q0
const int32_t *APSectionFactors, //Q15
int16_t lengthInOut,
int32_t *FilterState) //Q16
{
int n, j;
int32_t a, b;
for (j=0; j<ALLPASSSECTIONS; j++) {
for (n=0;n<lengthInOut;n+=2){
a = WEBRTC_SPL_MUL_16_32_RSFT16(InOut16[n], APSectionFactors[j]); //Q0*Q31=Q31 shifted 16 gives Q15
a <<= 1; // Q15 -> Q16
b = WebRtcSpl_AddSatW32(a, FilterState[j]); //Q16+Q16=Q16
// |a| in Q15 (Q0*Q31=Q31 shifted 16 gives Q15).
a = WEBRTC_SPL_MUL_16_32_RSFT16(b >> 16, -APSectionFactors[j]);
// FilterState[j]: Q15<<1 + Q0<<16 = Q16 + Q16 = Q16
FilterState[j] = WebRtcSpl_AddSatW32(a << 1, (uint32_t)InOut16[n] << 16);
InOut16[n] = (int16_t)(b >> 16); // Save as Q0.
}
}
}
void WebRtcIsacfix_DecimateAllpass32(const int16_t *in,
int32_t *state_in, /* array of size: 2*ALLPASSSECTIONS+1 */
int16_t N, /* number of input samples */
int16_t *out) /* array of size N/2 */
{
int n;
int16_t data_vec[PITCH_FRAME_LEN];
/* copy input */
memcpy(data_vec + 1, in, sizeof(int16_t) * (N - 1));
data_vec[0] = (int16_t)(state_in[2 * ALLPASSSECTIONS] >> 16); // z^-1 state.
state_in[2 * ALLPASSSECTIONS] = (uint32_t)in[N - 1] << 16;
AllpassFilterForDec32(data_vec+1, kApUpperQ15, N, state_in);
AllpassFilterForDec32(data_vec, kApLowerQ15, N, state_in+ALLPASSSECTIONS);
for (n=0;n<N/2;n++) {
out[n] = WebRtcSpl_AddSatW16(data_vec[2 * n], data_vec[2 * n + 1]);
}
}