1 /*
2 * RTP JPEG-compressed video Packetizer, RFC 2435
3 * Copyright (c) 2012 Samuel Pitoiset
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
26
28 {
31 int nb_qtables = 0;
32 uint8_t type = 1;
/* default pixel format is AV_PIX_FMT_YUVJ420P */
35 int off = 0;
/* fragment offset of the current JPEG frame */
37 int i;
38
41
42 /* convert video pixel dimensions from pixels to blocks */
45
46 /* check if pixel format is not the normal 420 case */
48 type = 0;
50 type = 1;
51 } else {
53 return;
54 }
55
56 /* preparse the header for getting some infos */
57 for (i = 0; i <
size; i++) {
58 if (buf[i] != 0xff)
59 continue;
60
61 if (buf[i + 1] ==
DQT) {
62 if (buf[i + 4])
64 "Only 8-bit precision is supported.\n");
65
66 /* a quantization table is 64 bytes long */
67 nb_qtables =
AV_RB16(&buf[i + 2]) / 65;
68 if (i + 4 + nb_qtables * 65 > size) {
70 return;
71 }
72
73 qtables = &buf[i + 4];
74 }
else if (buf[i + 1] ==
SOF0) {
75 if (buf[i + 14] != 17 || buf[i + 17] != 17) {
77 "Only 1x1 chroma blocks are supported. Aborted!\n");
78 return;
79 }
80 }
else if (buf[i + 1] ==
SOS) {
81 /* SOS is last marker in the header */
83 break;
84 }
85 }
86
87 /* skip JPEG header */
88 buf += i;
89 size -= i;
90
91 for (i = size - 2; i >= 0; i--) {
92 if (buf[i] == 0xff && buf[i + 1] ==
EOI) {
93 /* Remove the EOI marker */
94 size = i;
95 break;
96 }
97 }
98
100 while (size > 0) {
101 int hdr_size = 8;
102
103 if (off == 0 && nb_qtables)
104 hdr_size += 4 + 64 * nb_qtables;
105
106 /* payload max in one packet */
108
109 /* set main header */
110 bytestream_put_byte(&p, 0);
111 bytestream_put_be24(&p, off);
112 bytestream_put_byte(&p, type);
113 bytestream_put_byte(&p, 255);
114 bytestream_put_byte(&p, w);
115 bytestream_put_byte(&p, h);
116
117 if (off == 0 && nb_qtables) {
118 /* set quantization tables header */
119 bytestream_put_byte(&p, 0);
120 bytestream_put_byte(&p, 0);
121 bytestream_put_be16(&p, 64 * nb_qtables);
122
123 for (i = 0; i < nb_qtables; i++)
125 }
126
127 /* copy payload data */
128 memcpy(p, buf, len);
129
130 /* marker bit is last packet in frame */
132
137 }
138 }