1 /*
2 * RTP packetization for Xiph audio and video
3 * Copyright (c) 2010 Josh Allmann
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/avassert.h"
23 #include "libavutil/intreadwrite.h"
24
25 #include "avformat.h"
26 #include "rtpenc.h"
27
28 /**
29 * Packetize Xiph frames into RTP according to
30 * RFC 5215 (Vorbis) and the Theora RFC draft.
31 * (http://svn.xiph.org/trunk/theora/doc/draft-ietf-avt-rtp-theora-00.txt)
32 */
ff_rtp_send_xiph(AVFormatContext * s1,const uint8_t * buff,int size)33 void ff_rtp_send_xiph(AVFormatContext *s1, const uint8_t *buff, int size)
34 {
35 RTPMuxContext *s = s1->priv_data;
36 AVStream *st = s1->streams[0];
37 int max_pkt_size, xdt, frag;
38 uint8_t *q;
39
40 max_pkt_size = s->max_payload_size - 6; // ident+frag+tdt/vdt+pkt_num+pkt_length
41
42 // set xiph data type
43 switch (*buff) {
44 case 0x01: // vorbis id
45 case 0x05: // vorbis setup
46 case 0x80: // theora header
47 case 0x82: // theora tables
48 xdt = 1; // packed config payload
49 break;
50 case 0x03: // vorbis comments
51 case 0x81: // theora comments
52 xdt = 2; // comment payload
53 break;
54 default:
55 xdt = 0; // raw data payload
56 break;
57 }
58
59 // Set ident.
60 // Probably need a non-fixed way of generating
61 // this, but it has to be done in SDP and passed in from there.
62 q = s->buf;
63 *q++ = (RTP_XIPH_IDENT >> 16) & 0xff;
64 *q++ = (RTP_XIPH_IDENT >> 8) & 0xff;
65 *q++ = (RTP_XIPH_IDENT ) & 0xff;
66
67 // set fragment
68 // 0 - whole frame (possibly multiple frames)
69 // 1 - first fragment
70 // 2 - fragment continuation
71 // 3 - last fragment
72 frag = size <= max_pkt_size ? 0 : 1;
73
74 if (!frag && !xdt) { // do we have a whole frame of raw data?
75 uint8_t *end_ptr = s->buf + 6 + max_pkt_size; // what we're allowed to write
76 uint8_t *ptr = s->buf_ptr + 2 + size; // what we're going to write
77 int remaining = end_ptr - ptr;
78
79 av_assert1(s->num_frames <= s->max_frames_per_packet);
80 if (s->num_frames > 0 &&
81 (remaining < 0 ||
82 s->num_frames == s->max_frames_per_packet ||
83 av_compare_ts(s->cur_timestamp - s->timestamp, st->time_base,
84 s1->max_delay, AV_TIME_BASE_Q) >= 0)) {
85 // send previous packets now; no room for new data, or too much delay
86 ff_rtp_send_data(s1, s->buf, s->buf_ptr - s->buf, 0);
87 s->num_frames = 0;
88 }
89
90 // buffer current frame to send later
91 if (0 == s->num_frames)
92 s->timestamp = s->cur_timestamp;
93 s->num_frames++;
94
95 // Set packet header. Normally, this is OR'd with frag and xdt,
96 // but those are zero, so omitted here
97 *q++ = s->num_frames;
98
99 if (s->num_frames > 1)
100 q = s->buf_ptr; // jump ahead if needed
101 AV_WB16(q, size);
102 q += 2;
103 memcpy(q, buff, size);
104 q += size;
105 s->buf_ptr = q;
106
107 return;
108 } else if (s->num_frames) {
109 // immediately send buffered frames if buffer is not raw data,
110 // or if current frame is fragmented.
111 ff_rtp_send_data(s1, s->buf, s->buf_ptr - s->buf, 0);
112 }
113
114 s->timestamp = s->cur_timestamp;
115 s->num_frames = 0;
116 s->buf_ptr = q;
117 while (size > 0) {
118 int len = (!frag || frag == 3) ? size : max_pkt_size;
119 q = s->buf_ptr;
120
121 // set packet headers
122 *q++ = (frag << 6) | (xdt << 4); // num_frames = 0
123 AV_WB16(q, len);
124 q += 2;
125 // set packet body
126 memcpy(q, buff, len);
127 q += len;
128 buff += len;
129 size -= len;
130
131 ff_rtp_send_data(s1, s->buf, q - s->buf, 0);
132
133 frag = size <= max_pkt_size ? 3 : 2;
134 }
135 }
136