3 * Copyright (c) 2011 Justin Ruggles
5 * This file is part of FFmpeg.
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 #include "libavutil/avassert.h"
27 static void ac3_exponent_min_c(uint8_t *exp, int num_reuse_blocks, int nb_coefs)
31 if (!num_reuse_blocks)
34 for (i = 0; i < nb_coefs; i++) {
35 uint8_t min_exp = *exp;
36 uint8_t *exp1 = exp + 256;
37 for (blk = 0; blk < num_reuse_blocks; blk++) {
38 uint8_t next_exp = *exp1;
39 if (next_exp < min_exp)
47 static int ac3_max_msb_abs_int16_c(const int16_t *src, int len)
50 for (i = 0; i < len; i++)
55 static void ac3_lshift_int16_c(int16_t *src, unsigned int len,
58 uint32_t *src32 = (uint32_t *)src;
59 const uint32_t mask = ~(((1 << shift) - 1) << 16);
62 for (i = 0; i < len; i += 8) {
63 src32[i ] = (src32[i ] << shift) & mask;
64 src32[i+1] = (src32[i+1] << shift) & mask;
65 src32[i+2] = (src32[i+2] << shift) & mask;
66 src32[i+3] = (src32[i+3] << shift) & mask;
67 src32[i+4] = (src32[i+4] << shift) & mask;
68 src32[i+5] = (src32[i+5] << shift) & mask;
69 src32[i+6] = (src32[i+6] << shift) & mask;
70 src32[i+7] = (src32[i+7] << shift) & mask;
74 static void ac3_rshift_int32_c(int32_t *src, unsigned int len,
90 static void float_to_fixed24_c(int32_t *dst, const float *src, unsigned int len)
92 const float scale = 1 << 24;
94 *dst++ = lrintf(*src++ * scale);
95 *dst++ = lrintf(*src++ * scale);
96 *dst++ = lrintf(*src++ * scale);
97 *dst++ = lrintf(*src++ * scale);
98 *dst++ = lrintf(*src++ * scale);
99 *dst++ = lrintf(*src++ * scale);
100 *dst++ = lrintf(*src++ * scale);
101 *dst++ = lrintf(*src++ * scale);
106 static void ac3_bit_alloc_calc_bap_c(int16_t *mask, int16_t *psd,
108 int snr_offset, int floor,
109 const uint8_t *bap_tab, uint8_t *bap)
113 /* special case, if snr offset is -960, set all bap's to zero */
114 if (snr_offset == -960) {
115 memset(bap, 0, AC3_MAX_COEFS);
120 band = ff_ac3_bin_to_band_tab[start];
122 int m = (FFMAX(mask[band] - snr_offset - floor, 0) & 0x1FE0) + floor;
123 int band_end = FFMIN(ff_ac3_band_start_tab[band+1], end);
124 for (; bin < band_end; bin++) {
125 int address = av_clip((psd[bin] - m) >> 5, 0, 63);
126 bap[bin] = bap_tab[address];
128 } while (end > ff_ac3_band_start_tab[band++]);
131 static int ac3_compute_mantissa_size_c(int mant_cnt[5], uint8_t *bap,
137 for (i = 0; i < nb_coefs; i++) {
140 // bap=1 to bap=4 will be counted in compute_mantissa_size_final
142 } else if (b <= 13) {
143 // bap=5 to bap=13 use (bap-1) bits
146 // bap=14 uses 14 bits and bap=15 uses 16 bits
147 bits += (b == 14) ? 14 : 16;
153 static void ac3_extract_exponents_c(uint8_t *exp, int32_t *coef, int nb_coefs)
157 for (i = 0; i < nb_coefs; i++) {
159 int v = abs(coef[i]);
169 coef[i] = av_clip(coef[i], -16777215, 16777215);
176 av_cold void ff_ac3dsp_init(AC3DSPContext *c, int bit_exact)
178 c->ac3_exponent_min = ac3_exponent_min_c;
179 c->ac3_max_msb_abs_int16 = ac3_max_msb_abs_int16_c;
180 c->ac3_lshift_int16 = ac3_lshift_int16_c;
181 c->ac3_rshift_int32 = ac3_rshift_int32_c;
182 c->float_to_fixed24 = float_to_fixed24_c;
183 c->bit_alloc_calc_bap = ac3_bit_alloc_calc_bap_c;
184 c->compute_mantissa_size = ac3_compute_mantissa_size_c;
185 c->extract_exponents = ac3_extract_exponents_c;
188 ff_ac3dsp_init_arm(c, bit_exact);
190 ff_ac3dsp_init_x86(c, bit_exact);