FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavcodec/ac3dec_fixed.c
Date: 2026-08-28 05:02:41
Exec Total Coverage
Lines: 56 81 69.1%
Functions: 4 4 100.0%
Branches: 18 34 52.9%

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1 /*
2 * Copyright (c) 2012
3 * MIPS Technologies, Inc., California.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the MIPS Technologies, Inc., nor the names of its
14 * contributors may be used to endorse or promote products derived from
15 * this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE MIPS TECHNOLOGIES, INC. ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE MIPS TECHNOLOGIES, INC. BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * Author: Stanislav Ocovaj (socovaj@mips.com)
30 *
31 * AC3 fixed-point decoder for MIPS platforms
32 *
33 * This file is part of FFmpeg.
34 *
35 * FFmpeg is free software; you can redistribute it and/or
36 * modify it under the terms of the GNU Lesser General Public
37 * License as published by the Free Software Foundation; either
38 * version 2.1 of the License, or (at your option) any later version.
39 *
40 * FFmpeg is distributed in the hope that it will be useful,
41 * but WITHOUT ANY WARRANTY; without even the implied warranty of
42 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
43 * Lesser General Public License for more details.
44 *
45 * You should have received a copy of the GNU Lesser General Public
46 * License along with FFmpeg; if not, write to the Free Software
47 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
48 */
49
50 #include "config_components.h"
51 #define USE_FIXED 1
52 #include "ac3dec.h"
53 #include "codec_internal.h"
54 #define IMDCT_TYPE AV_TX_INT32_MDCT
55
56 #include "ac3dec.h"
57
58 /* Keep two fractional bits in fixed-point transform coefficients. */
59 #define AC3_FIXED_COEFF_BITS 2
60 #define AC3_FIXED_EXPONENT_MAX 24
61
62 64437 static av_always_inline int fixed_coeff_bits(const AC3DecodeContext *s)
63 {
64 /* ac3_fixed normally decodes AC-3. Keep Q0 when it is explicitly forced
65 * to decode E-AC-3, whose AHT coefficient bounds are different. */
66
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64437 return s->eac3 ? 0 : AC3_FIXED_COEFF_BITS;
67 }
68
69 static const int end_freq_inv_tab[8] =
70 {
71 50529027, 44278013, 39403370, 32292987, 27356480, 23729101, 20951060, 18755316
72 };
73
74 13548 static void scale_coefs (
75 int32_t *dst,
76 const int32_t *src,
77 int dynrng,
78 int len)
79 {
80 int i, shift;
81 unsigned mul, round;
82 int temp, temp1, temp2, temp3, temp4, temp5, temp6, temp7;
83
84 13548 mul = (dynrng & 0x1f) + 0x20;
85 13548 shift = 4 - (sign_extend(dynrng, 9) >> 5);
86
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13548 if (shift > 0 ) {
87 13548 round = 1 << (shift-1);
88
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447084 for (i=0; i<len; i+=8) {
89
90 433536 temp = src[i] * mul;
91 433536 temp1 = src[i+1] * mul;
92 433536 temp = temp + round;
93 433536 temp2 = src[i+2] * mul;
94
95 433536 temp1 = temp1 + round;
96 433536 dst[i] = temp >> shift;
97 433536 temp3 = src[i+3] * mul;
98 433536 temp2 = temp2 + round;
99
100 433536 dst[i+1] = temp1 >> shift;
101 433536 temp4 = src[i + 4] * mul;
102 433536 temp3 = temp3 + round;
103 433536 dst[i+2] = temp2 >> shift;
104
105 433536 temp5 = src[i+5] * mul;
106 433536 temp4 = temp4 + round;
107 433536 dst[i+3] = temp3 >> shift;
108 433536 temp6 = src[i+6] * mul;
109
110 433536 dst[i+4] = temp4 >> shift;
111 433536 temp5 = temp5 + round;
112 433536 temp7 = src[i+7] * mul;
113 433536 temp6 = temp6 + round;
114
115 433536 dst[i+5] = temp5 >> shift;
116 433536 temp7 = temp7 + round;
117 433536 dst[i+6] = temp6 >> shift;
118 433536 dst[i+7] = temp7 >> shift;
119
120 }
121 } else {
122 shift = -shift;
123 mul <<= shift;
124 for (i=0; i<len; i+=8) {
125
126 dst[i] = src[i ] * mul;
127 dst[i+1] = src[i+1] * mul;
128 dst[i+2] = src[i+2] * mul;
129 dst[i+3] = src[i+3] * mul;
130 dst[i+4] = src[i+4] * mul;
131 dst[i+5] = src[i+5] * mul;
132 dst[i+6] = src[i+6] * mul;
133 dst[i+7] = src[i+7] * mul;
134 }
135 }
136 13548 }
137
138 14772 static void scale_coefs_q2(int32_t *dst, const int32_t *src, int dynrng,
139 int len)
140 {
141 int i, shift;
142 int mul;
143
144 14772 mul = (dynrng & 0x1f) + 0x20;
145 14772 shift = 4 - (sign_extend(dynrng, 9) >> 5);
146
147 /* AC-3 mantissas have magnitude at most 2^23, hence Q2 coefficients
148 * have magnitude at most 2^25. Coupling uses MULH(coeff * 2^4, coord)
149 * with coord < 2^31, so coupled coefficients are below 2^28.
150 * Rematrixing can at most double them, keeping src below 2^29. */
151
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14772 if (dynrng == 32) {
152
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1366212 for (i = 0; i < len; i++)
153 1360896 dst[i] = src[i] * 4;
154 5316 return;
155 }
156
157
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9456 if (shift >= 4) {
158 9456 const int round = 1 << (shift - 1);
159 9456 const int unit = 1 << shift;
160
161 /* With shift >= 4, quotient * mul is below 2^25 * 63. Splitting
162 * quotient and remainder therefore keeps both products in int32_t. */
163
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2430192 for (i = 0; i < len; i++) {
164 2420736 int quotient = src[i] >> shift;
165 2420736 int remainder = src[i] - quotient * unit;
166
167 2420736 dst[i] = quotient * mul + ((remainder * mul + round) >> shift);
168 }
169 } else if (shift > 0) {
170 const int round = 1 << (shift - 1);
171
172 for (i = 0; i < len; i++)
173 dst[i] = av_clipl_int32(((int64_t)src[i] * mul + round) >> shift);
174 } else {
175 mul <<= -shift;
176 for (i = 0; i < len; i++)
177 dst[i] = av_clipl_int32((int64_t)src[i] * mul);
178 }
179 }
180
181 /**
182 * Downmix samples from original signal to stereo or mono (this is for 16-bit samples
183 * and fixed point decoder - original (for 32-bit samples) is in ac3dsp.c).
184 */
185 1 static void ac3_downmix_c_fixed16(int16_t **samples, int16_t **matrix,
186 int out_ch, int in_ch, int len)
187 {
188 int i, j;
189 int v0, v1;
190
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1 if (out_ch == 2) {
191 for (i = 0; i < len; i++) {
192 v0 = v1 = 0;
193 for (j = 0; j < in_ch; j++) {
194 v0 += samples[j][i] * matrix[0][j];
195 v1 += samples[j][i] * matrix[1][j];
196 }
197 samples[0][i] = (v0+2048)>>12;
198 samples[1][i] = (v1+2048)>>12;
199 }
200
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1 } else if (out_ch == 1) {
201
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257 for (i = 0; i < len; i++) {
202 256 v0 = 0;
203
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1280 for (j = 0; j < in_ch; j++)
204 1024 v0 += samples[j][i] * matrix[0][j];
205 256 samples[0][i] = (v0+2048)>>12;
206 }
207 }
208 1 }
209
210 #if CONFIG_EAC3_DECODER
211 #include "eac3dec.c"
212 #endif
213 #include "ac3dec.c"
214
215 static const AVOption options[] = {
216 { "cons_noisegen", "enable consistent noise generation", OFFSET(consistent_noise_generation), AV_OPT_TYPE_BOOL, {.i64 = 0 }, 0, 1, PAR },
217 { "drc_scale", "percentage of dynamic range compression to apply", OFFSET(drc_scale), AV_OPT_TYPE_FLOAT, {.dbl = 1.0}, 0.0, 6.0, PAR },
218 { "heavy_compr", "enable heavy dynamic range compression", OFFSET(heavy_compression), AV_OPT_TYPE_BOOL, {.i64 = 0 }, 0, 1, PAR },
219 { "downmix", "Request a specific channel layout from the decoder", OFFSET(downmix_layout), AV_OPT_TYPE_CHLAYOUT, {.str = NULL}, .flags = PAR },
220 { NULL},
221 };
222
223 static const AVClass ac3_decoder_class = {
224 .class_name = "Fixed-Point AC-3 Decoder",
225 .item_name = av_default_item_name,
226 .option = options,
227 .version = LIBAVUTIL_VERSION_INT,
228 };
229
230 const FFCodec ff_ac3_fixed_decoder = {
231 .p.name = "ac3_fixed",
232 CODEC_LONG_NAME("ATSC A/52A (AC-3)"),
233 .p.type = AVMEDIA_TYPE_AUDIO,
234 .p.id = AV_CODEC_ID_AC3,
235 .p.priv_class = &ac3_decoder_class,
236 .priv_data_size = sizeof (AC3DecodeContext),
237 .init = ac3_decode_init,
238 .flush = ac3_decode_flush,
239 .close = ac3_decode_end,
240 FF_CODEC_DECODE_CB(ac3_decode_frame),
241 .p.capabilities = AV_CODEC_CAP_CHANNEL_CONF |
242 AV_CODEC_CAP_DR1,
243 CODEC_SAMPLEFMTS(AV_SAMPLE_FMT_S16P),
244 .caps_internal = FF_CODEC_CAP_INIT_CLEANUP,
245 };
246