diff options
Diffstat (limited to 'third_party/libwebrtc/common_audio/signal_processing/refl_coef_to_lpc.c')
-rw-r--r-- | third_party/libwebrtc/common_audio/signal_processing/refl_coef_to_lpc.c | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/third_party/libwebrtc/common_audio/signal_processing/refl_coef_to_lpc.c b/third_party/libwebrtc/common_audio/signal_processing/refl_coef_to_lpc.c new file mode 100644 index 0000000000..b0858b2b0e --- /dev/null +++ b/third_party/libwebrtc/common_audio/signal_processing/refl_coef_to_lpc.c @@ -0,0 +1,59 @@ +/* + * 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_ReflCoefToLpc(). + * The description header can be found in signal_processing_library.h + * + */ + +#include "common_audio/signal_processing/include/signal_processing_library.h" + +void WebRtcSpl_ReflCoefToLpc(const int16_t *k, int use_order, int16_t *a) +{ + int16_t any[WEBRTC_SPL_MAX_LPC_ORDER + 1]; + int16_t *aptr, *aptr2, *anyptr; + const int16_t *kptr; + int m, i; + + kptr = k; + *a = 4096; // i.e., (Word16_MAX >> 3)+1. + *any = *a; + a[1] = *k >> 3; + + for (m = 1; m < use_order; m++) + { + kptr++; + aptr = a; + aptr++; + aptr2 = &a[m]; + anyptr = any; + anyptr++; + + any[m + 1] = *kptr >> 3; + for (i = 0; i < m; i++) + { + *anyptr = *aptr + (int16_t)((*aptr2 * *kptr) >> 15); + anyptr++; + aptr++; + aptr2--; + } + + aptr = a; + anyptr = any; + for (i = 0; i < (m + 2); i++) + { + *aptr = *anyptr; + aptr++; + anyptr++; + } + } +} |