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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 00:47:55 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 00:47:55 +0000 |
commit | 26a029d407be480d791972afb5975cf62c9360a6 (patch) | |
tree | f435a8308119effd964b339f76abb83a57c29483 /third_party/libwebrtc/common_audio/signal_processing/lpc_to_refl_coef.c | |
parent | Initial commit. (diff) | |
download | firefox-26a029d407be480d791972afb5975cf62c9360a6.tar.xz firefox-26a029d407be480d791972afb5975cf62c9360a6.zip |
Adding upstream version 124.0.1.upstream/124.0.1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'third_party/libwebrtc/common_audio/signal_processing/lpc_to_refl_coef.c')
-rw-r--r-- | third_party/libwebrtc/common_audio/signal_processing/lpc_to_refl_coef.c | 56 |
1 files changed, 56 insertions, 0 deletions
diff --git a/third_party/libwebrtc/common_audio/signal_processing/lpc_to_refl_coef.c b/third_party/libwebrtc/common_audio/signal_processing/lpc_to_refl_coef.c new file mode 100644 index 0000000000..7a5e25191b --- /dev/null +++ b/third_party/libwebrtc/common_audio/signal_processing/lpc_to_refl_coef.c @@ -0,0 +1,56 @@ +/* + * 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 function WebRtcSpl_LpcToReflCoef(). + * The description header can be found in signal_processing_library.h + * + */ + +#include "common_audio/signal_processing/include/signal_processing_library.h" + +#define SPL_LPC_TO_REFL_COEF_MAX_AR_MODEL_ORDER 50 + +void WebRtcSpl_LpcToReflCoef(int16_t* a16, int use_order, int16_t* k16) +{ + int m, k; + int32_t tmp32[SPL_LPC_TO_REFL_COEF_MAX_AR_MODEL_ORDER]; + int32_t tmp_inv_denom32; + int16_t tmp_inv_denom16; + + k16[use_order - 1] = a16[use_order] << 3; // Q12<<3 => Q15 + for (m = use_order - 1; m > 0; m--) + { + // (1 - k^2) in Q30 + tmp_inv_denom32 = 1073741823 - k16[m] * k16[m]; + // (1 - k^2) in Q15 + tmp_inv_denom16 = (int16_t)(tmp_inv_denom32 >> 15); + + for (k = 1; k <= m; k++) + { + // tmp[k] = (a[k] - RC[m] * a[m-k+1]) / (1.0 - RC[m]*RC[m]); + + // [Q12<<16 - (Q15*Q12)<<1] = [Q28 - Q28] = Q28 + tmp32[k] = (a16[k] << 16) - (k16[m] * a16[m - k + 1] << 1); + + tmp32[k] = WebRtcSpl_DivW32W16(tmp32[k], tmp_inv_denom16); //Q28/Q15 = Q13 + } + + for (k = 1; k < m; k++) + { + a16[k] = (int16_t)(tmp32[k] >> 1); // Q13>>1 => Q12 + } + + tmp32[m] = WEBRTC_SPL_SAT(8191, tmp32[m], -8191); + k16[m - 1] = (int16_t)WEBRTC_SPL_LSHIFT_W32(tmp32[m], 2); //Q13<<2 => Q15 + } + return; +} |