mirror of
https://github.com/google/liblc3.git
synced 2026-06-04 02:27:02 +00:00
Antoine Soulier
daa580235e
Duplicate interfaces for HR mode spec: Remove intermediate quantized table fix: legacy lc3_frame_bytes() and lc3_resolve_bitrate() Cosmetic: rename fast_xxx math function to lc3_xxx
55 lines
1.6 KiB
C
55 lines
1.6 KiB
C
/******************************************************************************
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*
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* Copyright 2022 Google LLC
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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******************************************************************************/
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#include "energy.h"
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#include "tables.h"
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/**
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* Energy estimation per band
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*/
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bool lc3_energy_compute(
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enum lc3_dt dt, enum lc3_srate sr, const float *x, float *e)
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{
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int nb = lc3_num_bands[dt][sr];
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const int *lim = lc3_band_lim[dt][sr];
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/* Mean the square of coefficients within each band */
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float e_sum[2] = { 0, 0 };
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int iband_h = nb - (const int []){
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[LC3_DT_2M5] = 2, [LC3_DT_5M ] = 3,
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[LC3_DT_7M5] = 4, [LC3_DT_10M] = 2 }[dt];
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for (int iband = 0, i = lim[iband]; iband < nb; iband++) {
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int ie = lim[iband+1];
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int n = ie - i;
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float sx2 = x[i] * x[i];
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for (i++; i < ie; i++)
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sx2 += x[i] * x[i];
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*e = sx2 / n;
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e_sum[iband >= iband_h] += *(e++);
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}
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/* Return the near nyquist flag */
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return e_sum[1] > 30 * e_sum[0];
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}
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