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;
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 /* get the pixel format type or fail */
50 type = 0;
54 type = 1;
55 } else {
57 return;
58 }
59
60 /* preparse the header for getting some infos */
61 for (i = 0; i <
size; i++) {
62 if (buf[i] != 0xff)
63 continue;
64
65 if (buf[i + 1] ==
DQT) {
66 if (buf[i + 4])
68 "Only 8-bit precision is supported.\n");
69
70 /* a quantization table is 64 bytes long */
71 nb_qtables =
AV_RB16(&buf[i + 2]) / 65;
72 if (i + 4 + nb_qtables * 65 > size) {
74 return;
75 }
76
77 qtables = &buf[i + 4];
78 }
else if (buf[i + 1] ==
SOF0) {
79 if (buf[i + 14] != 17 || buf[i + 17] != 17) {
81 "Only 1x1 chroma blocks are supported. Aborted!\n");
82 return;
83 }
84 }
else if (buf[i + 1] ==
SOS) {
85 /* SOS is last marker in the header */
87 break;
88 }
89 }
90
91 /* skip JPEG header */
92 buf += i;
93 size -= i;
94
95 for (i = size - 2; i >= 0; i--) {
96 if (buf[i] == 0xff && buf[i + 1] ==
EOI) {
97 /* Remove the EOI marker */
98 size = i;
99 break;
100 }
101 }
102
104 while (size > 0) {
105 int hdr_size = 8;
106
107 if (off == 0 && nb_qtables)
108 hdr_size += 4 + 64 * nb_qtables;
109
110 /* payload max in one packet */
112
113 /* set main header */
114 bytestream_put_byte(&p, 0);
115 bytestream_put_be24(&p, off);
116 bytestream_put_byte(&p, type);
117 bytestream_put_byte(&p, 255);
118 bytestream_put_byte(&p, w);
119 bytestream_put_byte(&p, h);
120
121 if (off == 0 && nb_qtables) {
122 /* set quantization tables header */
123 bytestream_put_byte(&p, 0);
124 bytestream_put_byte(&p, 0);
125 bytestream_put_be16(&p, 64 * nb_qtables);
126
127 for (i = 0; i < nb_qtables; i++)
129 }
130
131 /* copy payload data */
132 memcpy(p, buf, len);
133
134 /* marker bit is last packet in frame */
136
141 }
142 }