FFmpeg coverage

Directory: ../../../ffmpeg/
File: src/libavcodec/mpeg4audio.c
Date: 2026-08-26 10:34:04
Exec Total Coverage
Lines: 93 110 84.5%
Functions: 5 5 100.0%
Branches: 67 86 77.9%
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1 /*
2 * MPEG-4 Audio common code
3 * Copyright (c) 2008 Baptiste Coudurier <baptiste.coudurier@free.fr>
4 * Copyright (c) 2009 Alex Converse <alex.converse@gmail.com>
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23 #include "get_bits.h"
24 #include "mpeg4audio.h"
25
26 /**
27 * Parse MPEG-4 audio configuration for ALS object type.
28 * @param[in] gb bit reader context
29 * @param[in] c MPEG4AudioConfig structure to fill
30 * @return on success 0 is returned, otherwise a value < 0
31 */
32 21 static int parse_config_ALS(GetBitContext *gb, MPEG4AudioConfig *c, void *logctx)
33 {
34
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 21 if (get_bits_left(gb) < 112)
35 ✗ return AVERROR_INVALIDDATA;
36
37
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 21 if (get_bits_long(gb, 32) != MKBETAG('A','L','S','\0'))
38 ✗ return AVERROR_INVALIDDATA;
39
40 // override AudioSpecificConfig channel configuration and sample rate
41 // which are buggy in old ALS conformance files
42 21 c->sample_rate = get_bits_long(gb, 32);
43
44
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 21 if (c->sample_rate <= 0) {
45 ✗ av_log(logctx, AV_LOG_ERROR, "Invalid sample rate %d\n", c->sample_rate);
46 ✗ return AVERROR_INVALIDDATA;
47 }
48
49 // skip number of samples
50 21 skip_bits_long(gb, 32);
51
52 // read number of channels
53 21 c->chan_config = 0;
54 21 c->channels = get_bits(gb, 16) + 1;
55
56 21 return 0;
57 }
58
59 const uint8_t ff_mpeg4audio_channels[15] = {
60 0,
61 1, // mono (1/0)
62 2, // stereo (2/0)
63 3, // 3/0
64 4, // 3/1
65 5, // 3/2
66 6, // 3/2.1
67 8, // 5/2.1
68 0,
69 0,
70 0,
71 7, // 3/3.1
72 8, // 3/2/2.1
73 24, // 3/3/3 - 5/2/3 - 3/0/0.2
74 8, // 3/2.1 - 2/0
75 };
76
77 1027 static inline int get_object_type(GetBitContext *gb)
78 {
79 1027 int object_type = get_bits(gb, 5);
80
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 1027 if (object_type == AOT_ESCAPE)
81 69 object_type = 32 + get_bits(gb, 6);
82 1027 return object_type;
83 }
84
85 916 static inline int get_sample_rate(GetBitContext *gb, int *index)
86 {
87 916 *index = get_bits(gb, 4);
88
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 1811 return *index == 0x0f ? get_bits(gb, 24) :
89 895 ff_mpeg4audio_sample_rates[*index];
90 }
91
92 826 int ff_mpeg4audio_get_config_gb(MPEG4AudioConfig *c, GetBitContext *gb,
93 int sync_extension, void *logctx)
94 {
95 int specific_config_bitindex, ret;
96 826 int start_bit_index = get_bits_count(gb);
97 826 c->object_type = get_object_type(gb);
98 826 c->sample_rate = get_sample_rate(gb, &c->sampling_index);
99 826 c->chan_config = get_bits(gb, 4);
100
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 826 if (c->chan_config < FF_ARRAY_ELEMS(ff_mpeg4audio_channels))
101 826 c->channels = ff_mpeg4audio_channels[c->chan_config];
102 else {
103 ✗ av_log(logctx, AV_LOG_ERROR, "Invalid chan_config %d\n", c->chan_config);
104 ✗ return AVERROR_INVALIDDATA;
105 }
106 826 c->sbr = -1;
107 826 c->ps = -1;
108
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 826 if (c->object_type == AOT_SBR || (c->object_type == AOT_PS &&
109 // check for W6132 Annex YYYY draft MP3onMP4
110
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 3 !(show_bits(gb, 3) & 0x03 && !(show_bits(gb, 9) & 0x3F)))) {
111
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 6 if (c->object_type == AOT_PS)
112 3 c->ps = 1;
113 6 c->ext_object_type = AOT_SBR;
114 6 c->sbr = 1;
115 6 c->ext_sample_rate = get_sample_rate(gb, &c->ext_sampling_index);
116 6 c->object_type = get_object_type(gb);
117
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 6 if (c->object_type == AOT_ER_BSAC)
118 ✗ c->ext_chan_config = get_bits(gb, 4);
119 } else {
120 820 c->ext_object_type = AOT_NULL;
121 820 c->ext_sample_rate = 0;
122 }
123 826 specific_config_bitindex = get_bits_count(gb);
124
125
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 826 if (c->object_type == AOT_ALS) {
126 21 skip_bits(gb, 5);
127
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 21 if (show_bits(gb, 24) != MKBETAG('\0','A','L','S'))
128 ✗ skip_bits(gb, 24);
129
130 21 specific_config_bitindex = get_bits_count(gb);
131
132 21 ret = parse_config_ALS(gb, c, logctx);
133
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 21 if (ret < 0)
134 ✗ return ret;
135 }
136
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 826 switch (c->object_type) {
137 751 case AOT_AAC_MAIN:
138 case AOT_AAC_LC:
139 case AOT_AAC_SSR:
140 case AOT_AAC_LTP:
141 case AOT_ER_AAC_LC:
142 751 c->frame_length_short = get_bits1(gb);
143
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 751 c->frame_length = c->frame_length_short ? 960 : 1024;
144 751 break;
145 21 case AOT_ER_AAC_LD:
146 case AOT_ER_AAC_ELD:
147 21 c->frame_length_short = get_bits1(gb);
148
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 21 c->frame_length = c->frame_length_short ? 480 : 512;
149 21 break;
150 33 case AOT_USAC: {
151 int core_sbr_frame_len_idx, sbr_ratio;
152 int ratio_mult, ratio_dec, frame_length;
153
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 33 if (get_bits(gb, 5) == 0x1f) /* usacSamplingFrequencyIndex */ {
154 ✗ skip_bits(gb, 24); /* usacSamplingFrequency */
155 }
156 33 core_sbr_frame_len_idx = get_bits(gb, 3);
157
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 33 c->frame_length_short = core_sbr_frame_len_idx == 0 ||
158 core_sbr_frame_len_idx == 2;
159
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 66 sbr_ratio = core_sbr_frame_len_idx == 2 ? 2 :
160
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 33 core_sbr_frame_len_idx == 3 ? 3 :
161 33 core_sbr_frame_len_idx == 4 ? 1 :
162 0;
163
164
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 33 if (sbr_ratio == 2) {
165 ✗ ratio_mult = 8;
166 ✗ ratio_dec = 3;
167
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 33 } else if (sbr_ratio == 3) {
168 ✗ ratio_mult = 2;
169 ✗ ratio_dec = 1;
170
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 33 } else if (sbr_ratio == 4) {
171 ✗ ratio_mult = 4;
172 ✗ ratio_dec = 1;
173 } else {
174 33 ratio_mult = 1;
175 33 ratio_dec = 1;
176 }
177
178
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 33 frame_length = c->frame_length_short ? 768 : 1024;
179 33 c->frame_length = (frame_length * ratio_mult) / ratio_dec;
180 33 break;
181 }
182 }
183
184
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 826 if (c->ext_object_type != AOT_SBR && sync_extension) {
185
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 19299 while (get_bits_left(gb) > 15) {
186
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 18996 if (show_bits(gb, 11) == 0x2b7) { // sync extension
187 195 get_bits(gb, 11);
188 195 c->ext_object_type = get_object_type(gb);
189
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 195 if (c->ext_object_type == AOT_SBR && (c->sbr = get_bits1(gb)) == 1) {
190 84 c->ext_sample_rate = get_sample_rate(gb, &c->ext_sampling_index);
191
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 84 if (c->ext_sample_rate == c->sample_rate)
192 6 c->sbr = -1;
193 }
194
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 195 if (get_bits_left(gb) > 11 && get_bits(gb, 11) == 0x548)
195 30 c->ps = get_bits1(gb);
196 195 break;
197 } else
198 18801 get_bits1(gb); // skip 1 bit
199 }
200 }
201
202 //PS requires SBR
203
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 826 if (!c->sbr)
204 102 c->ps = 0;
205 //Limit implicit PS to the HE-AACv2 Profile
206
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 826 if ((c->ps == -1 && c->object_type != AOT_AAC_LC) || c->channels & ~0x01)
207 624 c->ps = 0;
208
209 826 return specific_config_bitindex - start_bit_index;
210 }
211
212 184 int avpriv_mpeg4audio_get_config2(MPEG4AudioConfig *c, const uint8_t *buf,
213 int size, int sync_extension, void *logctx)
214 {
215 GetBitContext gb;
216 int ret;
217
218
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 184 if (size <= 0)
219 1 return AVERROR_INVALIDDATA;
220
221 183 ret = init_get_bits8(&gb, buf, size);
222
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 183 if (ret < 0)
223 ✗ return ret;
224
225 183 return ff_mpeg4audio_get_config_gb(c, &gb, sync_extension, logctx);
226 }
227