1 /*
2 * AVC helper functions for muxers
3 * Copyright (c) 2006 Baptiste Coudurier <baptiste.coudurier@smartjog.com>
4 *
5 * This file is part of FFmpeg.
6 *
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.
11 *
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.
16 *
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
20 */
21
22 #include "libavutil/intreadwrite.h"
23 #include "libavcodec/h264.h"
24 #include "avformat.h"
25 #include "avio.h"
26 #include "avc.h"
27
ff_avc_find_startcode_internal(const uint8_t * p,const uint8_t * end)28 static const uint8_t *ff_avc_find_startcode_internal(const uint8_t *p, const uint8_t *end)
29 {
30 const uint8_t *a = p + 4 - ((intptr_t)p & 3);
31
32 for (end -= 3; p < a && p < end; p++) {
33 if (p[0] == 0 && p[1] == 0 && p[2] == 1)
34 return p;
35 }
36
37 for (end -= 3; p < end; p += 4) {
38 uint32_t x = *(const uint32_t*)p;
39 // if ((x - 0x01000100) & (~x) & 0x80008000) // little endian
40 // if ((x - 0x00010001) & (~x) & 0x00800080) // big endian
41 if ((x - 0x01010101) & (~x) & 0x80808080) { // generic
42 if (p[1] == 0) {
43 if (p[0] == 0 && p[2] == 1)
44 return p;
45 if (p[2] == 0 && p[3] == 1)
46 return p+1;
47 }
48 if (p[3] == 0) {
49 if (p[2] == 0 && p[4] == 1)
50 return p+2;
51 if (p[4] == 0 && p[5] == 1)
52 return p+3;
53 }
54 }
55 }
56
57 for (end += 3; p < end; p++) {
58 if (p[0] == 0 && p[1] == 0 && p[2] == 1)
59 return p;
60 }
61
62 return end + 3;
63 }
64
ff_avc_find_startcode(const uint8_t * p,const uint8_t * end)65 const uint8_t *ff_avc_find_startcode(const uint8_t *p, const uint8_t *end){
66 const uint8_t *out= ff_avc_find_startcode_internal(p, end);
67 if(p<out && out<end && !out[-1]) out--;
68 return out;
69 }
70
ff_avc_parse_nal_units(AVIOContext * pb,const uint8_t * buf_in,int size)71 int ff_avc_parse_nal_units(AVIOContext *pb, const uint8_t *buf_in, int size)
72 {
73 const uint8_t *p = buf_in;
74 const uint8_t *end = p + size;
75 const uint8_t *nal_start, *nal_end;
76
77 size = 0;
78 nal_start = ff_avc_find_startcode(p, end);
79 for (;;) {
80 while (nal_start < end && !*(nal_start++));
81 if (nal_start == end)
82 break;
83
84 nal_end = ff_avc_find_startcode(nal_start, end);
85 avio_wb32(pb, nal_end - nal_start);
86 avio_write(pb, nal_start, nal_end - nal_start);
87 size += 4 + nal_end - nal_start;
88 nal_start = nal_end;
89 }
90 return size;
91 }
92
ff_avc_parse_nal_units_buf(const uint8_t * buf_in,uint8_t ** buf,int * size)93 int ff_avc_parse_nal_units_buf(const uint8_t *buf_in, uint8_t **buf, int *size)
94 {
95 AVIOContext *pb;
96 int ret = avio_open_dyn_buf(&pb);
97 if(ret < 0)
98 return ret;
99
100 ff_avc_parse_nal_units(pb, buf_in, *size);
101
102 av_freep(buf);
103 *size = avio_close_dyn_buf(pb, buf);
104 return 0;
105 }
106
ff_isom_write_avcc(AVIOContext * pb,const uint8_t * data,int len)107 int ff_isom_write_avcc(AVIOContext *pb, const uint8_t *data, int len)
108 {
109 AVIOContext *sps_pb = NULL, *pps_pb = NULL;
110 uint8_t *buf = NULL, *end, *start = NULL;
111 uint8_t *sps = NULL, *pps = NULL;
112 uint32_t sps_size = 0, pps_size = 0;
113 int ret, nb_sps = 0, nb_pps = 0;
114
115 if (len <= 6)
116 return AVERROR_INVALIDDATA;
117
118 /* check for H.264 start code */
119 if (AV_RB32(data) != 0x00000001 &&
120 AV_RB24(data) != 0x000001) {
121 avio_write(pb, data, len);
122 return 0;
123 }
124
125 ret = ff_avc_parse_nal_units_buf(data, &buf, &len);
126 if (ret < 0)
127 return ret;
128 start = buf;
129 end = buf + len;
130
131 ret = avio_open_dyn_buf(&sps_pb);
132 if (ret < 0)
133 goto fail;
134 ret = avio_open_dyn_buf(&pps_pb);
135 if (ret < 0)
136 goto fail;
137
138 /* look for sps and pps */
139 while (end - buf > 4) {
140 uint32_t size;
141 uint8_t nal_type;
142 size = FFMIN(AV_RB32(buf), end - buf - 4);
143 buf += 4;
144 nal_type = buf[0] & 0x1f;
145
146 if (nal_type == 7) { /* SPS */
147 nb_sps++;
148 if (size > UINT16_MAX || nb_sps >= H264_MAX_SPS_COUNT) {
149 ret = AVERROR_INVALIDDATA;
150 goto fail;
151 }
152 avio_wb16(sps_pb, size);
153 avio_write(sps_pb, buf, size);
154 } else if (nal_type == 8) { /* PPS */
155 nb_pps++;
156 if (size > UINT16_MAX || nb_pps >= H264_MAX_PPS_COUNT) {
157 ret = AVERROR_INVALIDDATA;
158 goto fail;
159 }
160 avio_wb16(pps_pb, size);
161 avio_write(pps_pb, buf, size);
162 }
163
164 buf += size;
165 }
166 sps_size = avio_close_dyn_buf(sps_pb, &sps);
167 pps_size = avio_close_dyn_buf(pps_pb, &pps);
168
169 if (sps_size < 6 || !pps_size) {
170 ret = AVERROR_INVALIDDATA;
171 goto fail;
172 }
173
174 avio_w8(pb, 1); /* version */
175 avio_w8(pb, sps[3]); /* profile */
176 avio_w8(pb, sps[4]); /* profile compat */
177 avio_w8(pb, sps[5]); /* level */
178 avio_w8(pb, 0xff); /* 6 bits reserved (111111) + 2 bits nal size length - 1 (11) */
179 avio_w8(pb, 0xe0 | nb_sps); /* 3 bits reserved (111) + 5 bits number of sps */
180
181 avio_write(pb, sps, sps_size);
182 avio_w8(pb, nb_pps); /* number of pps */
183 avio_write(pb, pps, pps_size);
184
185 fail:
186 if (!sps)
187 avio_close_dyn_buf(sps_pb, &sps);
188 if (!pps)
189 avio_close_dyn_buf(pps_pb, &pps);
190 av_free(sps);
191 av_free(pps);
192 av_free(start);
193
194 return ret;
195 }
196
ff_avc_write_annexb_extradata(const uint8_t * in,uint8_t ** buf,int * size)197 int ff_avc_write_annexb_extradata(const uint8_t *in, uint8_t **buf, int *size)
198 {
199 uint16_t sps_size, pps_size;
200 uint8_t *out;
201 int out_size;
202
203 *buf = NULL;
204 if (*size >= 4 && (AV_RB32(in) == 0x00000001 || AV_RB24(in) == 0x000001))
205 return 0;
206 if (*size < 11 || in[0] != 1)
207 return AVERROR_INVALIDDATA;
208
209 sps_size = AV_RB16(&in[6]);
210 if (11 + sps_size > *size)
211 return AVERROR_INVALIDDATA;
212 pps_size = AV_RB16(&in[9 + sps_size]);
213 if (11 + sps_size + pps_size > *size)
214 return AVERROR_INVALIDDATA;
215 out_size = 8 + sps_size + pps_size;
216 out = av_mallocz(out_size + AV_INPUT_BUFFER_PADDING_SIZE);
217 if (!out)
218 return AVERROR(ENOMEM);
219 AV_WB32(&out[0], 0x00000001);
220 memcpy(out + 4, &in[8], sps_size);
221 AV_WB32(&out[4 + sps_size], 0x00000001);
222 memcpy(out + 8 + sps_size, &in[11 + sps_size], pps_size);
223 *buf = out;
224 *size = out_size;
225 return 0;
226 }
227
ff_avc_mp4_find_startcode(const uint8_t * start,const uint8_t * end,int nal_length_size)228 const uint8_t *ff_avc_mp4_find_startcode(const uint8_t *start,
229 const uint8_t *end,
230 int nal_length_size)
231 {
232 unsigned int res = 0;
233
234 if (end - start < nal_length_size)
235 return NULL;
236 while (nal_length_size--)
237 res = (res << 8) | *start++;
238
239 if (res > end - start)
240 return NULL;
241
242 return start + res;
243 }
244