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/* * AC-3 DSP functions * Copyright (c) 2011 Justin Ruggles * * This file is part of FFmpeg. * * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * FFmpeg is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #include "avcodec.h"#include "ac3.h"#include "ac3dsp.h"#include "mathops.h" static void ac3_exponent_min_c(uint8_t *exp, int num_reuse_blocks, int nb_coefs){    int blk, i;     if (!num_reuse_blocks)        return;     for (i = 0; i < nb_coefs; i++) {        uint8_t min_exp = *exp;        uint8_t *exp1 = exp + 256;        for (blk = 0; blk < num_reuse_blocks; blk++) {            uint8_t next_exp = *exp1;            if (next_exp < min_exp)                min_exp = next_exp;            exp1 += 256;        }        *exp++ = min_exp;    }} static int ac3_max_msb_abs_int16_c(const int16_t *src, int len){    int i, v = 0;    for (i = 0; i < len; i++)        v |= abs(src[i]);    return v;} static void ac3_lshift_int16_c(int16_t *src, unsigned int len,                               unsigned int shift){    uint32_t *src32 = (uint32_t *)src;    const uint32_t mask = ~(((1 << shift) - 1) << 16);    int i;    len >>= 1;    for (i = 0; i < len; i += 8) {        src32[i  ] = (src32[i  ] << shift) & mask;        src32[i+1] = (src32[i+1] << shift) & mask;        src32[i+2] = (src32[i+2] << shift) & mask;        src32[i+3] = (src32[i+3] << shift) & mask;        src32[i+4] = (src32[i+4] << shift) & mask;        src32[i+5] = (src32[i+5] << shift) & mask;        src32[i+6] = (src32[i+6] << shift) & mask;        src32[i+7] = (src32[i+7] << shift) & mask;    }} static void ac3_rshift_int32_c(int32_t *src, unsigned int len,                               unsigned int shift){    do {        *src++ >>= shift;        *src++ >>= shift;        *src++ >>= shift;        *src++ >>= shift;        *src++ >>= shift;        *src++ >>= shift;        *src++ >>= shift;        *src++ >>= shift;        len -= 8;    } while (len > 0);} static void float_to_fixed24_c(int32_t *dst, const float *src, unsigned int len){    const float scale = 1 << 24;    do {        *dst++ = lrintf(*src++ * scale);        *dst++ = lrintf(*src++ * scale);        *dst++ = lrintf(*src++ * scale);        *dst++ = lrintf(*src++ * scale);        *dst++ = lrintf(*src++ * scale);        *dst++ = lrintf(*src++ * scale);        *dst++ = lrintf(*src++ * scale);        *dst++ = lrintf(*src++ * scale);        len -= 8;    } while (len > 0);} static void ac3_bit_alloc_calc_bap_c(int16_t *mask, int16_t *psd,                                     int start, int end,                                     int snr_offset, int floor,                                     const uint8_t *bap_tab, uint8_t *bap){    int bin, band, band_end;     /* special case, if snr offset is -960, set all bap's to zero */    if (snr_offset == -960) {        memset(bap, 0, AC3_MAX_COEFS);        return;    }     bin  = start;    band = ff_ac3_bin_to_band_tab[start];    do {        int m = (FFMAX(mask[band] - snr_offset - floor, 0) & 0x1FE0) + floor;        band_end = ff_ac3_band_start_tab[++band];        band_end = FFMIN(band_end, end);         for (; bin < band_end; bin++) {            int address = av_clip_uintp2((psd[bin] - m) >> 5, 6);            bap[bin] = bap_tab[address];        }    } while (end > band_end);} static void ac3_update_bap_counts_c(uint16_t mant_cnt[16], uint8_t *bap,                                    int len){    while (len-- > 0)        mant_cnt[bap[len]]++;} DECLARE_ALIGNED(16, const uint16_t, ff_ac3_bap_bits)[16] = {    0,  0,  0,  3,  0,  4,  5,  6,  7,  8,  9, 10, 11, 12, 14, 16}; static int ac3_compute_mantissa_size_c(uint16_t mant_cnt[6][16]){    int blk, bap;    int bits = 0;     for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {        // bap=1 : 3 mantissas in 5 bits        bits += (mant_cnt[blk][1] / 3) * 5;        // bap=2 : 3 mantissas in 7 bits        // bap=4 : 2 mantissas in 7 bits        bits += ((mant_cnt[blk][2] / 3) + (mant_cnt[blk][4] >> 1)) * 7;        // bap=3 : 1 mantissa in 3 bits        bits += mant_cnt[blk][3] * 3;        // bap=5 to 15 : get bits per mantissa from table        for (bap = 5; bap < 16; bap++)            bits += mant_cnt[blk][bap] * ff_ac3_bap_bits[bap];    }    return bits;} static void ac3_extract_exponents_c(uint8_t *exp, int32_t *coef, int nb_coefs){    int i;     for (i = 0; i < nb_coefs; i++) {        int v = abs(coef[i]);        exp[i] = v ? 23 - av_log2(v) : 24;    }} static void ac3_sum_square_butterfly_int32_c(int64_t sum[4],                                             const int32_t *coef0,                                             const int32_t *coef1,                                             int len){    int i;     sum[0] = sum[1] = sum[2] = sum[3] = 0;     for (i = 0; i < len; i++) {        int lt = coef0[i];        int rt = coef1[i];        int md = lt + rt;        int sd = lt - rt;        MAC64(sum[0], lt, lt);        MAC64(sum[1], rt, rt);        MAC64(sum[2], md, md);        MAC64(sum[3], sd, sd);    }} static void ac3_sum_square_butterfly_float_c(float sum[4],                                             const float *coef0,                                             const float *coef1,                                             int len){    int i;     sum[0] = sum[1] = sum[2] = sum[3] = 0;     for (i = 0; i < len; i++) {        float lt = coef0[i];        float rt = coef1[i];        float md = lt + rt;        float sd = lt - rt;        sum[0] += lt * lt;        sum[1] += rt * rt;        sum[2] += md * md;        sum[3] += sd * sd;    }} static void ac3_downmix_c(float **samples, float (*matrix)[2],                          int out_ch, int in_ch, int len){    int i, j;    float v0, v1;    if (out_ch == 2) {        for (i = 0; i < len; i++) {            v0 = v1 = 0.0f;            for (j = 0; j < in_ch; j++) {                v0 += samples[j][i] * matrix[j][0];                v1 += samples[j][i] * matrix[j][1];            }            samples[0][i] = v0;            samples[1][i] = v1;        }    } else if (out_ch == 1) {        for (i = 0; i < len; i++) {            v0 = 0.0f;            for (j = 0; j < in_ch; j++)                v0 += samples[j][i] * matrix[j][0];            samples[0][i] = v0;        }    }} static void ac3_downmix_c_fixed(int32_t **samples, int16_t (*matrix)[2],                                int out_ch, int in_ch, int len){    int i, j;    int64_t v0, v1;    if (out_ch == 2) {        for (i = 0; i < len; i++) {            v0 = v1 = 0;            for (j = 0; j < in_ch; j++) {                v0 += (int64_t)samples[j][i] * matrix[j][0];                v1 += (int64_t)samples[j][i] * matrix[j][1];            }            samples[0][i] = (v0+2048)>>12;            samples[1][i] = (v1+2048)>>12;        }    } else if (out_ch == 1) {        for (i = 0; i < len; i++) {            v0 = 0;            for (j = 0; j < in_ch; j++)                v0 += (int64_t)samples[j][i] * matrix[j][0];            samples[0][i] = (v0+2048)>>12;        }    }} static void apply_window_int16_c(int16_t *output, const int16_t *input,                                 const int16_t *window, unsigned int len){    int i;    int len2 = len >> 1;     for (i = 0; i < len2; i++) {        int16_t w       = window[i];        output[i]       = (MUL16(input[i],       w) + (1 << 14)) >> 15;        output[len-i-1] = (MUL16(input[len-i-1], w) + (1 << 14)) >> 15;    }} av_cold void ff_ac3dsp_init(AC3DSPContext *c, int bit_exact){    c->ac3_exponent_min = ac3_exponent_min_c;    c->ac3_max_msb_abs_int16 = ac3_max_msb_abs_int16_c;    c->ac3_lshift_int16 = ac3_lshift_int16_c;    c->ac3_rshift_int32 = ac3_rshift_int32_c;    c->float_to_fixed24 = float_to_fixed24_c;    c->bit_alloc_calc_bap = ac3_bit_alloc_calc_bap_c;    c->update_bap_counts = ac3_update_bap_counts_c;    c->compute_mantissa_size = ac3_compute_mantissa_size_c;    c->extract_exponents = ac3_extract_exponents_c;    c->sum_square_butterfly_int32 = ac3_sum_square_butterfly_int32_c;    c->sum_square_butterfly_float = ac3_sum_square_butterfly_float_c;    c->downmix = ac3_downmix_c;    c->downmix_fixed = ac3_downmix_c_fixed;    c->apply_window_int16 = apply_window_int16_c;     if (ARCH_ARM)        ff_ac3dsp_init_arm(c, bit_exact);    if (ARCH_X86)        ff_ac3dsp_init_x86(c, bit_exact);    if (ARCH_MIPS)        ff_ac3dsp_init_mips(c, bit_exact);}

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