webrtc/modules/audio_coding/codecs/isac/fix/source/lattice_c.c
Mirko Bonadei bb547203bf Moving src/webrtc into src/.
In order to eliminate the WebRTC Subtree mirror in Chromium, 
WebRTC is moving the content of the src/webrtc directory up
to the src/ directory.

NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
TBR=tommi@webrtc.org

Bug: chromium:611808
Change-Id: Iac59c5b51b950f174119565bac87955a7994bc38
Reviewed-on: https://webrtc-review.googlesource.com/1560
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Henrik Kjellander <kjellander@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#19845}
2017-09-15 04:25:06 +00:00

49 lines
1.6 KiB
C

/*
* 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.
*/
/*
* Contains the core loop function for the lattice filter AR routine
* for iSAC codec.
*
*/
#include "settings.h"
#include "signal_processing_library.h"
#include "webrtc/typedefs.h"
/* Filter ar_g_Q0[] and ar_f_Q0[] through an AR filter with coefficients
* cth_Q15[] and sth_Q15[].
*/
void WebRtcIsacfix_FilterArLoop(int16_t* ar_g_Q0, // Input samples
int16_t* ar_f_Q0, // Input samples
int16_t* cth_Q15, // Filter coefficients
int16_t* sth_Q15, // Filter coefficients
size_t order_coef) { // order of the filter
int n = 0;
for (n = 0; n < HALF_SUBFRAMELEN - 1; n++) {
size_t k = 0;
int16_t tmpAR = 0;
int32_t tmp32 = 0;
int32_t tmp32_2 = 0;
tmpAR = ar_f_Q0[n + 1];
for (k = order_coef; k > 0; k--) {
tmp32 = (cth_Q15[k - 1] * tmpAR - sth_Q15[k - 1] * ar_g_Q0[k - 1] +
16384) >> 15;
tmp32_2 = (sth_Q15[k - 1] * tmpAR + cth_Q15[k - 1] * ar_g_Q0[k - 1] +
16384) >> 15;
tmpAR = (int16_t)WebRtcSpl_SatW32ToW16(tmp32);
ar_g_Q0[k] = (int16_t)WebRtcSpl_SatW32ToW16(tmp32_2);
}
ar_f_Q0[n + 1] = tmpAR;
ar_g_Q0[0] = tmpAR;
}
}