FFmpeg coverage

Directory: ../../../ffmpeg/
File: src/libavformat/nal.c
Date: 2025-04-25 22:50:00
Exec Total Coverage
Lines: 82 96 85.4%
Functions: 8 9 88.9%
Branches: 72 86 83.7%
Line Branch Exec Source
1 /*
2 * NAL helper functions for muxers
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21 #include <stdint.h>
22 #include <string.h>
23
24 #include "libavutil/mem.h"
25 #include "libavutil/error.h"
26 #include "libavcodec/defs.h"
27 #include "avio.h"
28 #include "avio_internal.h"
29 #include "nal.h"
30
31 2655 static const uint8_t *nal_find_startcode_internal(const uint8_t *p, const uint8_t *end)
32 {
33 2655 const uint8_t *a = p + 4 - ((intptr_t)p & 3);
34
35
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 9433 for (end -= 3; p < a && p < end; p++) {
36
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 7569 if (p[0] == 0 && p[1] == 0 && p[2] == 1)
37 791 return p;
38 }
39
40
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 584031 for (end -= 3; p < end; p += 4) {
41 583280 uint32_t x = *(const uint32_t*)p;
42 // if ((x - 0x01000100) & (~x) & 0x80008000) // little endian
43 // if ((x - 0x00010001) & (~x) & 0x00800080) // big endian
44
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 583280 if ((x - 0x01010101) & (~x) & 0x80808080) { // generic
45
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 8125 if (p[1] == 0) {
46
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 2536 if (p[0] == 0 && p[2] == 1)
47 248 return p;
48
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 2288 if (p[2] == 0 && p[3] == 1)
49 403 return p+1;
50 }
51
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 7474 if (p[3] == 0) {
52
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 2434 if (p[2] == 0 && p[4] == 1)
53 232 return p+2;
54
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 2202 if (p[4] == 0 && p[5] == 1)
55 230 return p+3;
56 }
57 }
58 }
59
60
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 1887 for (end += 3; p < end; p++) {
61
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 1136 if (p[0] == 0 && p[1] == 0 && p[2] == 1)
62 ✗ return p;
63 }
64
65 751 return end + 3;
66 }
67
68 2655 const uint8_t *ff_nal_find_startcode(const uint8_t *p, const uint8_t *end){
69 2655 const uint8_t *out = nal_find_startcode_internal(p, end);
70
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 2655 if(p<out && out<end && !out[-1]) out--;
71 2655 return out;
72 }
73
74 751 static int nal_parse_units(AVIOContext *pb, NALUList *list,
75 const uint8_t *buf_in, int size)
76 {
77 751 const uint8_t *p = buf_in;
78 751 const uint8_t *end = p + size;
79 const uint8_t *nal_start, *nal_end;
80
81 751 size = 0;
82 751 nal_start = ff_nal_find_startcode(p, end);
83 1904 for (;;) {
84 2655 const size_t nalu_limit = SIZE_MAX / sizeof(*list->nalus);
85
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 7411 while (nal_start < end && !*(nal_start++));
86
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 2655 if (nal_start == end)
87 751 break;
88
89 1904 nal_end = ff_nal_find_startcode(nal_start, end);
90
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 1904 if (pb) {
91 1576 avio_wb32(pb, nal_end - nal_start);
92 1576 avio_write(pb, nal_start, nal_end - nal_start);
93
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 328 } else if (list->nb_nalus >= nalu_limit) {
94 ✗ return AVERROR(ERANGE);
95 } else {
96 328 NALU *tmp = av_fast_realloc(list->nalus, &list->nalus_array_size,
97 328 (list->nb_nalus + 1) * sizeof(*list->nalus));
98
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 328 if (!tmp)
99 ✗ return AVERROR(ENOMEM);
100 328 list->nalus = tmp;
101 328 tmp[list->nb_nalus++] = (NALU){ .offset = nal_start - p,
102 328 .size = nal_end - nal_start };
103 }
104 1904 size += 4 + nal_end - nal_start;
105 1904 nal_start = nal_end;
106 }
107 751 return size;
108 }
109
110 662 int ff_nal_parse_units(AVIOContext *pb, const uint8_t *buf_in, int size)
111 {
112 662 return nal_parse_units(pb, NULL, buf_in, size);
113 }
114
115 89 int ff_nal_units_create_list(NALUList *list, const uint8_t *buf, int size)
116 {
117 89 list->nb_nalus = 0;
118 89 return nal_parse_units(NULL, list, buf, size);
119 }
120
121 89 void ff_nal_units_write_list(const NALUList *list, AVIOContext *pb,
122 const uint8_t *buf)
123 {
124
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 417 for (unsigned i = 0; i < list->nb_nalus; i++) {
125 328 avio_wb32(pb, list->nalus[i].size);
126 328 avio_write(pb, buf + list->nalus[i].offset, list->nalus[i].size);
127 }
128 89 }
129
130 9 int ff_nal_parse_units_buf(const uint8_t *buf_in, uint8_t **buf, int *size)
131 {
132 AVIOContext *pb;
133 9 int ret = avio_open_dyn_buf(&pb);
134
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 9 if(ret < 0)
135 ✗ return ret;
136
137 9 ff_nal_parse_units(pb, buf_in, *size);
138
139 9 *size = avio_close_dyn_buf(pb, buf);
140 9 return 0;
141 }
142
143 ✗ const uint8_t *ff_nal_mp4_find_startcode(const uint8_t *start,
144 const uint8_t *end,
145 int nal_length_size)
146 {
147 ✗ unsigned int res = 0;
148
149 ✗ if (end - start < nal_length_size)
150 ✗ return NULL;
151 ✗ while (nal_length_size--)
152 ✗ res = (res << 8) | *start++;
153
154 ✗ if (res > end - start)
155 ✗ return NULL;
156
157 ✗ return start + res;
158 }
159
160 54 uint8_t *ff_nal_unit_extract_rbsp(const uint8_t *src, uint32_t src_len,
161 uint32_t *dst_len, int header_len)
162 {
163 uint8_t *dst;
164 uint32_t i, len;
165
166 54 dst = av_malloc(src_len + AV_INPUT_BUFFER_PADDING_SIZE);
167
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 54 if (!dst)
168 ✗ return NULL;
169
170 /* NAL unit header */
171 54 i = len = 0;
172
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 156 while (i < header_len && i < src_len)
173 102 dst[len++] = src[i++];
174
175
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 4278 while (i + 2 < src_len)
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 4224 if (!src[i] && !src[i + 1] && src[i + 2] == 3) {
177 86 dst[len++] = src[i++];
178 86 dst[len++] = src[i++];
179 86 i++; // remove emulation_prevention_three_byte
180 } else
181 4138 dst[len++] = src[i++];
182
183
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 162 while (i < src_len)
184 108 dst[len++] = src[i++];
185
186 54 memset(dst + len, 0, AV_INPUT_BUFFER_PADDING_SIZE);
187
188 54 *dst_len = len;
189 54 return dst;
190 }
191