1/*
2 * RTP packetization for MPEG video
3 * Copyright (c) 2002 Fabrice Bellard
4 * Copyright (c) 2007 Luca Abeni
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 "libavcodec/mpegvideo.h"
24#include "avformat.h"
25#include "rtpenc.h"
26
27/* NOTE: a single frame must be passed with sequence header if
28   needed. XXX: use slices. */
29void ff_rtp_send_mpegvideo(AVFormatContext *s1, const uint8_t *buf1, int size)
30{
31    RTPMuxContext *s = s1->priv_data;
32    int len, h, max_packet_size;
33    uint8_t *q;
34    int begin_of_slice, end_of_slice, frame_type, temporal_reference;
35
36    max_packet_size = s->max_payload_size;
37    begin_of_slice = 1;
38    end_of_slice = 0;
39    frame_type = 0;
40    temporal_reference = 0;
41
42    while (size > 0) {
43        int begin_of_sequence;
44
45        begin_of_sequence = 0;
46        len = max_packet_size - 4;
47
48        if (len >= size) {
49            len = size;
50            end_of_slice = 1;
51        } else {
52            const uint8_t *r, *r1;
53            int start_code;
54
55            r1 = buf1;
56            while (1) {
57                start_code = -1;
58                r = ff_find_start_code(r1, buf1 + size, &start_code);
59                if((start_code & 0xFFFFFF00) == 0x100) {
60                    /* New start code found */
61                    if (start_code == 0x100) {
62                        frame_type = (r[1] & 0x38) >> 3;
63                        temporal_reference = (int)r[0] << 2 | r[1] >> 6;
64                    }
65                    if (start_code == 0x1B8) {
66                        begin_of_sequence = 1;
67                    }
68
69                    if (r - buf1 - 4 <= len) {
70                        /* The current slice fits in the packet */
71                        if (begin_of_slice == 0) {
72                            /* no slice at the beginning of the packet... */
73                            end_of_slice = 1;
74                            len = r - buf1 - 4;
75                            break;
76                        }
77                        r1 = r;
78                    } else {
79                        if ((r1 - buf1 > 4) && (r - r1 < max_packet_size)) {
80                            len = r1 - buf1 - 4;
81                            end_of_slice = 1;
82                        }
83                        break;
84                    }
85                } else {
86                    break;
87                }
88            }
89        }
90
91        h = 0;
92        h |= temporal_reference << 16;
93        h |= begin_of_sequence << 13;
94        h |= begin_of_slice << 12;
95        h |= end_of_slice << 11;
96        h |= frame_type << 8;
97
98        q = s->buf;
99        *q++ = h >> 24;
100        *q++ = h >> 16;
101        *q++ = h >> 8;
102        *q++ = h;
103
104        memcpy(q, buf1, len);
105        q += len;
106
107        /* 90kHz time stamp */
108        s->timestamp = s->cur_timestamp;
109        ff_rtp_send_data(s1, s->buf, q - s->buf, (len == size));
110
111        buf1 += len;
112        size -= len;
113        begin_of_slice = end_of_slice;
114        end_of_slice = 0;
115    }
116}
117
118
119